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DIY Stompboxes => Building your own stompbox => Topic started by: Kipper4 on February 19, 2017, 06:48:37 AM

Title: calling all Car and Tractor specialist
Post by: Kipper4 on February 19, 2017, 06:48:37 AM
How do those little parking sensors work on cars, you know the ones that do the proximity thing.

Could they have a use in a stomp box?

Naturally I'm thinking wah again.........
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 19, 2017, 07:09:13 AM
https://youtu.be/TJt_JFd90lU

Might be worth buying a cheapo kit and messung with it..

Not sure what those sensors are though???...
Title: Re: calling all Car and Tractor specialist
Post by: bool on February 19, 2017, 07:11:31 AM
Quote from: deadastronaut on February 19, 2017, 07:09:13 AM
...

Not sure what those sensors are though???...

Groupie sensors.
Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on February 19, 2017, 07:31:03 AM
I saw a demonstration a long time ago. Truck confidently reverses towards concrete bollard. Crunch. Technology wasn't too good then.
This is ultrasonic sonar. I think the ones now have a single, sealed ultrasonic transducer. Commonly tuned at 40Khz. A single pulse out then await the echo. Pretty simple job for a small microcontroller. Long ago, I don't think any were sealed, and 2 units were also used, one Transmit and one Receive.
I have actually spent some time monkeying around with ultrasonics in audio. Different than the usual  listening to bats thing. Might post something in the lounge about it, because none if it is stompbox specific.

A cheap way to get some to play with is one of those car security interior alarms. Gets you a pair of transducers already mounted on screened cable and a 40kHz 12v transmitter source and a preamp for the receiver (which will probably work at 9v too).
CPC have a good range of transducers and one of the very few to stock the 40Khz watch crystal to get a stable source for 40k transducers.

Title: Re: calling all Car and Tractor specialist
Post by: digi2t on February 19, 2017, 08:56:57 AM
OK, I'll bite...

I'm thinking, that the reason their using ultrasonic sonar is because there's some reasonable distance to be covered. I mean, you want to "see" that car or bollard at a point where you have time to react.

As far as a wah is concerned, using it for say, treadle position, would be overkill, if not really a suitable application. For the short distance that needs to be covered, there are plenty of tried and tested proximity sensor arrangements that already exist on the market. My Sonuus Wahoo uses this technology, and it works very well indeed. No pot to wear out.

Now... if you wanted to maybe connect an ultrasonic sonar to your wah to react to where on the stage your at, now that might be cool. If you have a stage big enough to bounce around on. Might be something that would spin Ben Weinman's crank.  ;D
Title: Re: calling all Car and Tractor specialist
Post by: slacker on February 19, 2017, 12:12:32 PM
I made a synth CV generator thing using infrared distance sensors like these https://www.rapidonline.com/robot-electronics-sharp-infrared-distance-sensors-554062 (https://www.rapidonline.com/robot-electronics-sharp-infrared-distance-sensors-554062) basically like a Theremin. It works pretty well, the output need some lowpass filtering because the sensor puts out a stepped voltage not a continuously variable signal but apart from that you don't need much more circuitry.
I thought about using it to make an expression pedal but I agree with what Dino said, I don't think they have enough resolution to work over the 2 or 3 inches of range that a waggling foot would have.
Title: Re: calling all Car and Tractor specialist
Post by: robthequiet on February 19, 2017, 06:35:58 PM
...basically like a Theremin.

I wonder if IR sensors might work, maybe enhanced with an IR sending lamp.
Title: Re: calling all Car and Tractor specialist
Post by: thermionix on February 19, 2017, 07:14:18 PM
wah probe
Title: Re: calling all Car and Tractor specialist
Post by: Jdansti on February 19, 2017, 07:58:36 PM
The only problem is your pedal will start beeping every time a person gets near it.
Title: Re: calling all Car and Tractor specialist
Post by: bluebunny on February 20, 2017, 02:41:41 AM
I hear these new-fangled ones will reverse onto your pedalboard all by themselves.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 20, 2017, 03:25:38 AM
put a wah circuit in a ford mondeo and roll it forward n back ..

the advantage of the ford mondeo is, it has a cup/beer holder too ;D
Title: Re: calling all Car and Tractor specialist
Post by: digi2t on February 20, 2017, 06:40:28 AM
Quote from: bluebunny on February 20, 2017, 02:41:41 AM
I hear these new-fangled ones will reverse onto your pedalboard all by themselves.

Yeah, hopefully that one won't be put together by the same people that brought us the self-parking Volvo...

Title: Re: calling all Car and Tractor specialist
Post by: duck_arse on February 20, 2017, 09:05:25 AM
I heard googoo was trialling a new, playerless wah.
Title: Re: calling all Car and Tractor specialist
Post by: bluebunny on February 20, 2017, 09:23:59 AM
Ba-dum, tsss!

(that was done without a drummer, natch...)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 20, 2017, 09:40:57 AM
Quote from: thermionix on February 19, 2017, 07:14:18 PM
wah probe

Do what?
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 20, 2017, 11:12:38 AM
"there are plenty of tried and tested proximity sensor arrangements that already exist on the market"


Please share if you have used one.
Thanks
Title: Re: calling all Car and Tractor specialist
Post by: bluebunny on February 20, 2017, 12:16:21 PM
Quote from: Kipper4 on February 20, 2017, 11:12:38 AM
Please share if you have used one.

Someone please tell Volvo.
Title: Re: calling all Car and Tractor specialist
Post by: bluebunny on February 20, 2017, 12:16:48 PM
Sorry, Rich.  We're not helping, are we?   :icon_redface:
Title: Re: calling all Car and Tractor specialist
Post by: Cozybuilder on February 20, 2017, 12:24:17 PM
Not approved by a professional Bullfighter?
Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on February 20, 2017, 12:38:02 PM
QuoteI heard googoo was trialling a new, playerless wah.
Isn't that a voice activated drone wah? No wait, that's Amazon...
As you were.

[serious] Rich, whatever the most suitable method of proximity sensing is, depends on whatever it is you want to waggle around to control your wah [/serious]

It may not be safe to assume you want to use a rocker pedal - could be some kind of body part or whatever.

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 20, 2017, 12:52:31 PM
I was thinking of it like a treadleless wah.
Using the foot for proximity.
But something that would work whatever the light situation. Dark stage set to sunlit room.

Title: Re: calling all Car and Tractor specialist
Post by: thermionix on February 20, 2017, 02:09:35 PM
Quote from: Kipper4 on February 20, 2017, 09:40:57 AM
Quote from: thermionix on February 19, 2017, 07:14:18 PM
wah probe

Do what?

Zvex Wah Probe.  Theremin-like proximity control.
Title: Re: calling all Car and Tractor specialist
Post by: karbomusic on February 20, 2017, 02:39:12 PM
Quote from: Kipper4 on February 20, 2017, 12:52:31 PM
I was thinking of it like a treadleless wah.
Using the foot for proximity.
But something that would work whatever the light situation. Dark stage set to sunlit room.



I've considered using some "Johnny 5 eyes" with an Arduino nano, should be simple enough...

https://www.amazon.com/Elegoo-HC-SR04-Ultrasonic-Distance-MEGA2560/dp/B01COSN7O6/

They are pretty simple in code (examples should be easy to find) and you could use its measurement to modulate a PWM on one of the Arduino output pins. I have a few of these lying around, I should dork around with one and use a LED on the PWM output for testing.

Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on February 20, 2017, 02:39:39 PM
Ok, so I know this works in principle 'cause I've already done it for some other devious purpose.

Need - u/s transmitter (Tx) 40kHz small dia like 10mm if possible. Ditto 40kHz receiver (Rx).

Circuit - 40khz oscillator to drive TX - Preamp for Rx - 2 input Exclusive OR gate (XOR) - RC filter - DC buffer.

Principle - Transmitted u/s wave is reflected back from target. Amplified RX signal is phase compared by XOR. Resulting phase difference pulses are averaged by RC to give a variable control voltage proportional to distance of target. The control voltage is buffered/scaled to drive the control current of an OTA.

For really short distances, a CD4046 chip can do everything except buffer the output control volts. Use it's VCO output tuned to 40kHz to drive the Tx and Signal input direct from Rx. Use its Phase comparator type 1 (XOR) output to RC filter. For longer distances a preamp will be needed for the Rx.
Provided a regulated supply for the 4046 and good quality timing RC parts, should be stable enough 40kHz for whock wan whoal. I've had one on BB over a few days with a scope channel always measuring the VCO freq while I was messing with it, and it never drifted by enough that mattered.

For bigger distance the Tx needs amplifying. You can use a bunch of gates or inverters in parallel/bridge drive combinations. Even small audio amp 386 & similar etc for single or bridge drive. Tx don't need sine wave, just whack it with the square from the 4046 VCO. A very good sinewave always comes back from the Rx, simply because any harmonic of 40Khz is way above Rx & Tx bandwidth.


Title: Re: calling all Car and Tractor specialist
Post by: karbomusic on February 20, 2017, 03:13:12 PM
Quote
I have a few of these lying around, I should dork around with one and use a LED on the PWM output for testing.


I just did, I think the closer working distances (and/or resolution) you need might be a little small for these. It works, but using my hand isn't the best test and it would take some potential error smoothing to keep things smooth in a real world scenario me thinks.
Title: Re: calling all Car and Tractor specialist
Post by: PRR on February 20, 2017, 03:30:02 PM
> How do those little parking sensors work

They beep/listen and let the main computer figure it out.

So not a drop-in solution for you.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 20, 2017, 04:46:38 PM
 Guess I can't squeeze a tractor for into a car sized box.

I'm looking for a mini solution that would fit in an enclosure along with the effect pcb.
Sorry to be a pain.
Title: Re: calling all Car and Tractor specialist
Post by: Jdansti on February 20, 2017, 05:58:51 PM
Quote from: Kipper4 on February 20, 2017, 12:52:31 PM
I was thinking of it like a treadleless wah.
Using the foot for proximity.
But something that would work whatever the light situation. Dark stage set to sunlit room.

Infrared LED and sensor like the ones on automatic faucets, toilets, soap dispensers, burglar alarms, etc. No problems with ambient light. The sensors are often photo transistors. See the links below.

https://www.societyofrobots.com/schematics_infraredemitdet.shtml

http://maxembedded.com/2013/08/how-to-build-an-ir-sensor/

For a wah, you'd have to figure out how to make the output variable and not on/off like a switch. Someone here should be able to tell you how.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 21, 2017, 06:42:57 AM
hi rich, heres a nifty lil circuit...

might give this a go myself at some point.. 8)


https://www.youtube.com/watch?v=AmkYwvCjXoY
Title: Re: calling all Car and Tractor specialist
Post by: samhay on February 21, 2017, 06:47:49 AM
>For a wah, you'd have to figure out how to make the output variable and not on/off like a switch. Someone here should be able to tell you how.

Light travels a bit faster than sound - about 3.0e+8 m/s (0.3 billion meters per second; or roughly 1 billion feet/s), which makes this a bit more tricky:

Lets say your toe moves at most about 15cm from heel down to heel up.
Light has to bounce off your foot and return to the sensor, so will have a difference in length of twice this = 30 cm (~1 foot).
Light will travel this distance in ~ 1 ns ( 1 billionth of a second).
Sampling an echo (by the detector and associated processing) must occur at least as fast as 1/ns = 1 GHz.
If you want some graduated effect, you have to be able to sample the light much faster than this = many GHz.
It's easy to sample this fast in the analogue domain, but if you need a computer to turn your detector into something you can pass audio through, then this is going to be rather difficult to pull off.

Edit - I forgot something. The further your foot is from the light source, the more light will be scattered away rather than bounced straight back to the detector. So, instead of listening for an echo, this should work quite well by measuring the intensity of the light that makes it back to the sensor. Using an IR light source should minimize problems caused by ambient light triggering the detector.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 21, 2017, 07:15:47 AM
dumb question, but do the RX/TX led sensors work in 'any' light conditions?.

Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on February 21, 2017, 08:23:15 AM
Passive infrared sensors used in alarms, can contain 2 Rx measured in a differential manner. One can see the world though the lens, the other reacts only to ambient. Therefore it detects some new source of heat/IR no matter what the background conditions because common ambient picked up by both is cancelled out. It's an optical humbucker. But the bad news is they contains basic detection circuitry that only has a switched output.
See differential detection....
https://en.wikipedia.org/wiki/Passive_infrared_sensor

They do jitter though when the external source is moving, so you might get lucky if you treat the output as a train of pulses which you average with an RC or integrator for a CV, or maybe an LED on a LDR will smooth it out for you. You may have to cover the lens with something that cuts the IR down for close up sensing.


Title: Re: calling all Car and Tractor specialist
Post by: duck_arse on February 21, 2017, 09:15:39 AM
[/helpfull]
Quote from: PRR on February 20, 2017, 03:30:02 PM
They beep/listen and let the main computer figure it out.

sounds like deadastronaut.

[helpfull]
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 21, 2017, 09:56:35 AM
it does... 8)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 21, 2017, 10:52:43 AM
Cheers guys
The IR transistors looks like a workable solution for now.
I'll get some and have a play
Rich
Much work to do.
Title: Re: calling all Car and Tractor specialist
Post by: amptramp on February 21, 2017, 12:07:22 PM
There are a lot of slotted limit switches available, some with an unbuffered open collector output:

http://www.digikey.com/products/en/sensors-transducers/optical-sensors-photointerrupters-slot-type-logic-output/547
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 21, 2017, 12:22:03 PM
Thanks Ron.
So a bit like an all in one package of transmitter and reciever.
From what I can gather from the data sheet. 1st one one the page.
Interesting.
As soon as I get some free time I'll look at some of the other solutions too.
Thanks guys
Title: Re: calling all Car and Tractor specialist
Post by: vigilante397 on February 21, 2017, 01:11:23 PM
This was mentioned a couple times with no apparent acknowledgement. This is exactly what you're talking about, ZVex has had it for a while.

http://www.zvex.com/products/wah-probe

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 21, 2017, 01:52:01 PM
I will go look for the probe schematic too thanks Nathan.

Getting out of the bath tonight, Glancing across the room. The scales caught my eye.
How does that work? Pressure pad? Induction?
Just throwing ideas out still at this stage.
Title: Re: calling all Car and Tractor specialist
Post by: amptramp on February 21, 2017, 05:39:52 PM
Scales typically use a load cell and this is a perfectly good solution.  They tend to be linear and appear electrically as a Wheatstone bridge with resistance dependent on applied force.
Title: Re: calling all Car and Tractor specialist
Post by: amptramp on February 21, 2017, 11:51:07 PM
You can also use linear variable differential transformers.  This is a transformer with a moveable core where there are two windings that are wired in series opposition.  Move it in one direction and the AC voltage increases.  Move it the other way and it increases but in the opposite phase.  It requires some circuitry, namely, an AC source (AC line voltage is OK) and an output amplifier that is also a phase detector, multiplying the output with the input signal.  For a rotary control, synchros, selsyns and resolvers have been used for years in aircraft instruments.  There are lots of options - you just have to decide on cost, complexity and suitability for the intended purpose.
Title: Re: calling all Car and Tractor specialist
Post by: duck_arse on February 22, 2017, 08:51:18 AM
Quote from: Kipper4 on February 21, 2017, 01:52:01 PM
.....
Getting out of the bath tonight,  ......

that time of year again already?

if you want IR transistor/diode/receiver, hack open an old mouse, one with one ball will have at least two sets.
Title: Re: calling all Car and Tractor specialist
Post by: feddozz on February 22, 2017, 09:08:04 AM
Quote from: deadastronaut on February 21, 2017, 06:42:57 AM
hi rich, heres a nifty lil circuit...

might give this a go myself at some point.. 8)


https://www.youtube.com/watch?v=AmkYwvCjXoY

This looks brilliantly simple. I wander if it actually works: does it gives a gradual increase in LED brightness, is the sweep  comfortable? H own close can the foot get to the sensor/emitter?

Has anybody implemented it yet?
Title: Re: calling all Car and Tractor specialist
Post by: EBK on February 22, 2017, 09:28:35 AM
Quote from: duck_arse on February 22, 2017, 08:51:18 AM
hack open an old mouse, one with one ball . . .
Before you do that, you should probably ask him how he lost his other ball.  He might have some interesting stories to tell.
(https://cdn.instructables.com/FZS/6QAD/H5R9EPOA/FZS6QADH5R9EPOA.MEDIUM.jpg)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 22, 2017, 02:42:03 PM
Lots of good options here.
I'm glad I asked.

Cheeky git Stephen.
Title: Re: calling all Car and Tractor specialist
Post by: thermionix on February 22, 2017, 03:00:29 PM
Quote from: EBK on February 22, 2017, 09:28:35 AM
Quote from: duck_arse on February 22, 2017, 08:51:18 AM
hack open an old mouse, one with one ball . . .
Before you do that, you should probably ask him how he lost his other ball.  He might have some interesting stories to tell.

I'm reminded of "The Rodeo Song"...still cracks me up every time I hear it.  Probably NSFDIYSB so you can look it up on youtube if so inclined.

"Well it's 40 below and..."
Title: Re: calling all Car and Tractor specialist
Post by: Jdansti on February 22, 2017, 05:51:20 PM
Quote from: deadastronaut on February 21, 2017, 06:42:57 AM
hi rich, heres a nifty lil circuit...

might give this a go myself at some point.. 8)


https://www.youtube.com/watch?v=AmkYwvCjXoY


Based on comments for the video, if you need the LED to be normally on and turn off as your foot gets closer to the sensor, then use a PNP transistor. If you want me he opposite, use NPN. I assume for a wah, you'd use a vactrol with the LED end connected where the LED is shown on his schematic.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 22, 2017, 06:26:31 PM
John, yup..

thats how i,d implement it...

i have some RX TX on order, its so simple its worth a bread up anyway.. 8)

see how it responds...

wah, vol, whatever...
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 24, 2017, 05:12:05 AM
Hi guys,

i pulled some 3mm RX TX leds from an old light sensor night light thingy,..

and have that guys circuit on breadboard...

works great, i swapped his 100k pot for a 1M....

i get about 1.5 inch range before it starts to light up....

the action is very smooth too....a nice rising light...cool.

i might get my 5mm ones in the post today, so i,ll see how they perform..

see if the range differs etc...works perfectly in total darkness and normal light conditions too..

im running it on 9v...

note, the RX,TX leds have to be butted up to each other....

great lil circuit....

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 24, 2017, 04:54:24 PM
So what should i search for to make the circuit D.A. made please.
photo transistors. Photo diodes?

ie what is a Tx Rx?
Title: Re: calling all Car and Tractor specialist
Post by: EBK on February 24, 2017, 05:05:32 PM
Tx=Transmitter Rx= Receiver

Sometimes called an IR matched pair or emitter/detector pair or a photo detector or a photogate....
Title: Re: calling all Car and Tractor specialist
Post by: thermionix on February 24, 2017, 05:06:26 PM
Quote from: Kipper4 on February 24, 2017, 04:54:24 PM
what is a Tx Rx?

Texas prescription drug?

No, probably transmit/receive.

(Edit- beat by EBK)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 24, 2017, 06:06:30 PM
Thanks you guys are too much :):)

So maybe these will fit the bill

http://www.hobbytronics.co.uk/infra-red-tx-rx

https://www.proto-pic.co.uk/infrared-emitters-and-detectors-pair.html

https://www.rapidonline.com/osram-matched-t1-frac34-infrared-emitter-and-detector-pairs-29406
Title: Re: calling all Car and Tractor specialist
Post by: feddozz on February 25, 2017, 03:28:08 AM
If you are in the UK look at bitsbox.com
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 25, 2017, 03:37:04 AM
Will do Vince. Thanks
I love their wire bundles.

https://www.bitsbox.co.uk/index.php?main_page=index&cPath=172_180&zenid=usce55o0ticum3b7q8p0ddpr74


nice choice. (not affiliated)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 25, 2017, 04:51:01 AM
This Ir sensor has some nice potential applications.
interactive gain control for dirt boxs
speed and depth in tremolos, vibes.
swellers
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 25, 2017, 04:55:31 AM
Great stuff as soon as I get back off holiday. I'll breadboard some stuff.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 25, 2017, 05:04:21 AM
Get the 5mm ones...

you get 2 sets off ebay for 1.79.

8)

i got the 3mm ones by mistake, have ordered the 5mm,s...

with the 3mm,s you get around 1.5" range....roughly an average wah pedal gap..

but with the 5mm,s the guy on the vid has a much longer range....better adjustment etc...
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 25, 2017, 05:40:19 AM
Thanks Rob. I think I saw those last night browsing.
I'll order some when I return.

I also have, unrelated, some of these. I bought hoping to use one day.
http://www.bitsbox.co.uk/data/optos/4N35.pdf
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 25, 2017, 05:44:06 AM
I like the look of the led type packaged ones that can be poked through the enclosure but will probably be weary of the spacing which I guess could be critical.
Whats your experience with spacings Rob?
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 25, 2017, 01:47:52 PM
They like to be butted right up to each other side by side....

Yeah get the led shape.... 8)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 25, 2017, 02:08:40 PM
Cheers man.
Title: Re: calling all Car and Tractor specialist
Post by: Jdansti on February 26, 2017, 12:48:53 AM
Quote from: deadastronaut on February 25, 2017, 05:04:21 AM
Get the 5mm ones...

you get 2 sets off ebay for 1.79.

8)

i got the 3mm ones by mistake, have ordered the 5mm,s...

with the 3mm,s you get around 1.5" range....roughly an average wah pedal gap..

but with the 5mm,s the guy on the vid has a much longer range....better adjustment etc...

If you still don't get an appropriate range, try adding one or more additional IR emitters (with their own resistors) so you can reflect more IR light back down to the sensor.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 26, 2017, 06:32:44 AM
Cheers john,  i,ll give that a whirl...

drew up the classic morley wah, and will add this to it later..

then try to switch between wah/vol..... 8)

ive got a chepo plastic vol pedal i can butcher...
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 26, 2017, 06:56:58 AM
You love that Morley don't ya Rob?
Is it the mfb filter?
I'm about to board a plane. I'll try it with a svf when I'm back at the breadboard.
Hope it goes ok. :)
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 26, 2017, 10:48:57 AM
Hi rich,  have a great holiday man,

yeah its a great simple, tweakable wah...no inductors etc...
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 26, 2017, 05:08:49 PM
Yer thanks man will do.
I like the Morley too. You used a tweeted version in the light wah (crying time) didn't you?
I built the crying time.
IIRC I preferred the sound of a 4558 chip it was somewhat creamier than a tl072, might just be my ears or bad memory.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on February 26, 2017, 09:47:51 PM
crying time?..never heard of it...
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on February 27, 2017, 03:17:46 AM
Jon did a version of the light wah without the light.
Maybe I just renamed it. Let me go search.

Apparently on Madbeans. I can't remember my log in so can't leave a link.
Half a job....
Title: Re: calling all Car and Tractor specialist
Post by: feddozz on March 03, 2017, 10:59:27 AM
Could someone suggest a good wah circuit that can be used with the ir sensors?
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 03, 2017, 11:13:21 AM
Iductorless wah for example.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 04, 2017, 05:07:05 AM
Or morley,

idiot wah...

btw i got my 5mm Rx tx  much better range, and adjustment..

going to have to experiment with how they should be mounted....as they like being butted

Right up next to each other....hmmmm...i,ll pop em in a pice of card and see how they perform


bear in mind that it could be used for all sorts of uses, not just wah, vol....

Title: Re: calling all Car and Tractor specialist
Post by: Jdansti on March 04, 2017, 03:52:13 PM
>bear in mind that it could be used for all sorts of uses, not just wah, vol....


Yep. I'm going to use them to turn LEDs on and off on a panel I'll mount inside the house to let me know if the garage doors are open or closed.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 06, 2017, 06:55:08 AM
2 IR pairs ordered.
Here I go.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 11, 2017, 04:23:27 PM
Proximty sensor drawing trial.
Anyone confirm I got this right please
Unsure of reciver orientation.....
Just using a common or garden PNP jelly bean.....


(http://i.imgur.com/fkkBDiZ.png)
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 11, 2017, 04:29:45 PM
i found the 2 RX (BLACK) with TX in the middle worked well.. 8)

(https://dl.dropboxusercontent.com/u/7464107/INFRAREDCIRCUIT.jpg)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 11, 2017, 10:49:13 PM
I think I smoked my Tx Rx.
I know I smoked a 1M pot. I reccomend putting a series R with the lug to V+ at this stage.

Anyway of checking if i did damage the Tx  Rx?
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 11, 2017, 11:00:17 PM
just did a rough test with the ohm meter and the photo diode i used for the test circuit is measuring in the kilohms region.
The spare I didnt use is measuring in the megohms region.

Any ideas on how to test an infrared led guys?
edit. When I check the forward voltage it measures 1v2 Is this a good sign?
link to data
http://www.digikey.co.uk/catalog/en/partgroup/3mm-infrared-led-emitters/11333

Title: Re: calling all Car and Tractor specialist
Post by: Jdansti on March 12, 2017, 01:56:51 AM
Try checking continuity in both directions. You should have continuity in one direction but not the other.
Title: Re: calling all Car and Tractor specialist
Post by: samhay on March 12, 2017, 03:49:09 AM
>Any ideas on how to test an infrared led guys?

Do you have a digital camera? The detector in these (and presumably in your phone) can 'see' well into the near-IR, so if you point the camera at the LED (while LED is on) and look through the view screen, you should be able to see the LED.
You can check this by looking at a TV, stereo, whatever remote. The LED in the end of these should come on when you press a button.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 05:46:40 AM
Thanks guys
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 06:17:10 AM
John your test doesnt work.
just to be sure i tried it on other diode too.

I wonder if they ever lit up at all. I was under the impression I wouldnt see a glow at all.
Dont ask "Something I read on the net"
Then I crack open a mouse and the led in there is like a super bright red. Maybe thats what it is and not an infra red led. It glows.

I did order 10 more pairs last night.

Still havent done your test yet sam.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 06:23:01 AM
Something defo went wrong last night when testing because I also fried the std 5mm led.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 06:33:02 AM


"if you point the camera at the LED (while LED is on) and look through the view screen, you should be able to see the LED.
You can check this by looking at a TV, stereo, whatever remote. The LED in the end of these should come on when you press a button."

Tried this with a remote and yes it does.



I'll give it a whirl with the IR 3mm leds.
lab report.
Nope I SMOKED 'em. Ziltch on the camera. As dead as the proverbial parrot. They are NO more.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 06:51:00 AM
Maybe next time I'll try this beauty.

https://circuitdigest.com/electronic-circuits/ir-sensor-circuit-diagram
Title: Re: calling all Car and Tractor specialist
Post by: amptramp on March 12, 2017, 07:13:23 AM
Your test circuit has no resistance in series with the LED.  As soon as the transistor is biased into conduction, unlimited (at least, much higher than needed) current flows through the LED.  You need a resistor in series with the LED to give you controllable current.  A resistor in series with the collector will protect the transistor and the LED but will not give you linear control - it would be on/off.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 08:20:11 AM
Cheers Ron

Judging by the little video for the lm358 circuit it is not linear either.

I did get the transistor circuit working for about 5min before it smoked the 1M pot and blew the IR leds and Photodiode. and it was working quite well just wasnt sure about the range of near / far.
Edit; with a 2N5087 pnp
Edit 2: I just found a pair of BC560 same series and data sheet as the BC557.
Title: Re: calling all Car and Tractor specialist
Post by: amptramp on March 12, 2017, 08:34:41 AM
D2 and D4 pull the transistor base to full conduction and they have no current limiting either.  The only way one of them survives is that one has a slightly lower forward voltage and keeps the other from conducting.  The type of circuit you need is a current source because the current is what you want to set.  There are a couple of examples of a current source here:

http://electronics.stackexchange.com/questions/28546/what-exactly-is-a-current-source
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 12, 2017, 09:01:58 AM
Just double checked over my breadboard,  and the schemo i posted is fine...

Works well, around 3" range..
Title: Re: calling all Car and Tractor specialist
Post by: duck_arse on March 12, 2017, 10:33:08 AM
kipper, there's two types of mouse. one has a ball that drives some rotary encoder wheel things (2 off), with an IR Tx/Rx pair looking thu the holes. the other has a pair of laser diodes that look at the surface as it moves, but I don't know if they are IR. they usually shine a bright red light on the surface as well. I went back to ball mouses, couldn't tame the optical ones.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 11:00:17 AM
I rebreaded the transistor circuit and it worked for a while.
This breadboard is a piece of trash.
after swapping a 2n5087 for a bc560 its stopped working again and the voltages are slammed at the +rail.

Whats your volts Dead un please?

@Duck un thanks for the info bud.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 11:06:17 AM
What kinda pot are you using Dead un please cuz I've now fried 3x my little tayda 9mm breadboard pots.
This makes me sad.........
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 12, 2017, 11:31:41 AM
yeah, im using a 9mm pot on breadboard same as yours... :icon_eek:

hang on...i'll knock up my breadboard layout...as i have it ok.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 12, 2017, 11:58:59 AM
here ya go...using 9v pp3 battery...

bc557..

(https://dl.dropboxusercontent.com/u/7464107/WAVES%20FOR%20PELLE/PROXIMITY.jpg)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 12:15:46 PM
Thanks Rob I'll have anther go later.
No body  sad battery I'm using a wall wart with 1amp.
Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 12, 2017, 12:22:22 PM
should be ok...

i just rigged it up to my 10 way daisy chain...9v, 2.4 amp adapter..

was fine..

better response too.. 8)

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 12:33:51 PM
Ok thanks
I got to boss this I can see it being really useful and fun for my grandsons robot projects.
I must have the fecker wired wrang.
Cheers
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 12, 2017, 03:18:48 PM
I breadboarded it the same as yours Rob and its working and the range (distance) is decent.
lab report. drum roll..... da da daaaah

under normal interior light conditions

the first thing to say is my IR transmitters are defo gone to the parrot sanctuary in the sky.
It didnt stop the IR detectors working in circuit.

The only leds i could get to work with it where 5mm diffuse green and diffuse blue.
none of the super brights really shone. super brite white, yellow, red or 3mm diffuse red.
suggesting it needs a higher Fv led.

using a 2N5087 pnp


Can It be done with npn or reverse the led so it goes from dark to light. Instead of just light to dark. Maybe some functioning IR transmitter will cure this.

Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 12, 2017, 05:59:16 PM
cool, 8)


''Can It be done with npn or reverse the led''

john referred to this earlier, havent tried it though...

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 13, 2017, 10:38:01 AM
Yeppers must have missed that post I'll try it later.
Also found a similar functioning circuit with a mosfet.
I'll have a go at that too and yock up a drawing.
Rich
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 13, 2017, 04:15:07 PM
Rob
Did you try different couloured leds in yours?

What didnt you like about the 5mm IR Tx &Tr?

I tried the npn but since my IR leds are blown it dint work.
Awaiting a bunch of 10 pair of 5mms in the post hopefully tommorow.
Then I can play some more.

Title: Re: calling all Car and Tractor specialist
Post by: deadastronaut on March 14, 2017, 02:34:37 PM
The 5mm are fine,

with the power supply connected rather than a battery
it has a much better tweakable range...

and will likey be ok with just the RX TX...   without the extra RX.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 01:26:30 PM
I got the 5mm Tx Tr today. They work a treat. Happy days.
Made a few adjustments to the basic detector network. More later.
Back to the breadboard. Meanwhile here's a concept idea.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 01:29:33 PM
An Infra Tremolo whose depth would be controlled by the detector.
I've yet to trial it and determine further values and check that the lfo waggles.

image removed

change r24 to 47k and the lfo is a good un.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 02:57:18 PM
R18=6k8
R10=100k

The IR detector and its led Clr as yet untested values to be determined

Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 15, 2017, 03:12:42 PM
Rich,
I think something must be wrong with the NPN/PNP diagrams.  You make it look like a PNP is just an upside down NPN....
Should all the diodes be reversed and supply voltages flipped or something similar?
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 04:07:57 PM
I dunno Eric. Maybe someone can confirm this?
I thought thats how I had it wired on the BB. I've been wrong before.

However I've had it working and with the detector as is the led is either on or off.
Although to the ear it seems to fade a bit.
Further work is required but its proof of concept on the breadboard.
I think the R10,R18 needs more work.

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 04:08:30 PM
Image removed

or so I thought.....
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 04:22:09 PM
Your right sir I apologise I'll repost with the corrected npn board.
I can tell you that cost me a few jellybeans and leds to find out.
More ghetto lab reports.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 04:43:34 PM
Ooops
try this

(http://i.imgur.com/z8X3T4S.png)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 04:46:42 PM
Guys you better strap in and be prepared to leave your fingerprints on the top of some jellybeans.
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 15, 2017, 04:56:49 PM
Quote from: Kipper4 on March 15, 2017, 04:22:09 PM
Your right sir I apologise I'll repost with the corrected npn board.
I can tell you that cost me a few jellybeans and leds to find out.
More ghetto lab reports.
I might just be misunderstanding your circuit....  I'll take another look when my mind is fresh.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 15, 2017, 05:08:19 PM
Above is an amended drawing. Hopefully right this time.
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 10:13:00 AM
Quote from: deadastronaut on February 21, 2017, 06:42:57 AM
hi rich, heres a nifty lil circuit...

might give this a go myself at some point.. 8)


https://www.youtube.com/watch?v=AmkYwvCjXoY
Anyone have a low bandwidth version of this, i.e., a schematic instead of a YouTube video?  So irritating waiting for this to buffer just so this guy can tell me what the next part on his table is.  :icon_mad:
Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on March 16, 2017, 10:38:32 AM
Sorry Rich, I don't think you switch between NPN & PNP just by swapping the emitter over. The one you show at top for NPN looks right, but can you see the PNP version would have it's base-emitter reversed all the time?
A PNP would act somehow if the emitter is moved to face the indicator LED's, but I'm not sure if that action would be suitable.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 11:57:30 AM
Thanks guys I think I have it now.
Please tell me if I still got it wrong....

renewed schematic
(http://i.imgur.com/9BwKrV0.png)

and for good measure the guy from the youtube vids schematic (screenshot)
(http://i.imgur.com/W22qFQJ.jpg)
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 01:01:07 PM
This is what I would expect to see as the PNP circuit, assuming your NPN circuit is correct:
(http://i.imgur.com/g4fG0f5.jpg)

Again, I may be misunderstanding your intent.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 01:43:44 PM
The intent is to provide one IR detector that will go from led dark to light OR
and alternative that will go from led light to dark.

NOT to use both and switch between the two detectors.

I have the you my pnp IR detector on the breadboard now Including the 3k3 and 1K resistors.
Ghetto Lab Report results

In faint evening light it goes : led goes dark to light.

With the window blinds closed : led dark to light same as above.

I'll breadboard yours later Eric.

Now for a test on my NPN from the previous picture post. I'll be back with another Ghetto Lab Report in two ticks.

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 03:01:16 PM
As far as I can tell from the NPN I have on the breadboard now the IR detector diodes are orientated wrong in the last drawing.

ie; + (long leg) of the detector goes to gnd.

Ghetto Lab Report.

Once the above ammendments have been done to the last posted pic

I tried it with
2n5088 tick
2N2222 tick
2n3094 tick
Mpas14 (Darlington) Tick
findings where that a lower gain transistor seemed better response.

I'll post up the corrected drawing.

Still havent tried your PNP detector Eric. Have you?

Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 03:04:58 PM
Please note the led CLRs

(http://i.imgur.com/COG7P7W.png)
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 03:13:58 PM
Quote from: Kipper4 on March 16, 2017, 03:01:16 PM
Still havent tried your PNP detector Eric. Have you?
I wouldn't bother.  You'll find it is equivalent to the NPN....  :icon_neutral:
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 03:22:12 PM
Everything worked out with your detector Eric EXCEPT one thing the IR detector needs the + (anode -Long leg) to Gnd not +9v

So like this

(http://i.imgur.com/DSaY6DP.png)
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 03:29:00 PM
However this pans out, whichever IR detector one uses.
It will need to be and external detector sens' pot.
The reason being It reacts completely different in low light and full light.
This could be an issue on stage if there are extremes of light conditions unless light conditions are known before use by the user at the expected time of use.


Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 03:34:04 PM
Quote from: Kipper4 on March 16, 2017, 03:22:12 PM
Everything worked out with your detector Eric EXCEPT one thing the IR detector needs the + (anode -Long leg) to Gnd not +9v
I also had the indicator and vactrol LEDs pointed the other way.  Oh well.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 04:03:14 PM
Shoot I'll double check my breadboard later.
Thanks Eric.

Ghetto lab demo later maybe.
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 04:30:14 PM
Quote from: Kipper4 on March 16, 2017, 03:29:00 PM
However this pans out, whichever IR detector one uses.
It will need to be and external detector sens' pot.
The reason being It reacts completely different in low light and full light.
This could be an issue on stage if there are extremes of light conditions unless light conditions are known before use by the user at the expected time of use.
This is why typical circuits modulate the signal before emitting it as IR and demodulate the received light.  Let's you throw out the ambient.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 05:04:56 PM
I'm sorry I don't understand your last post Eric. Please could you explain further.
Thanks
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 05:39:46 PM
Here is some additional info (mostly applicable to digital data, but applicable here as well with modification): https://learn.sparkfun.com/tutorials/ir-communication
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 16, 2017, 06:04:45 PM
Ok Gottya now thanks for that. In a nutshell the IR transmitter needs to be waggled and the receiver needs to be unwaggled to potentially negate the need for an external pot.

I can't help but feel this would significantly up the cost and size in such a simple idea.
I'm not against the idea of modulation and demodulation.
I guess it might depend also on if a single waggler could be used to do both processes too.

I still have some other potential IR detectors I have not investigated as yet.
I knew there would be pitfall hopefully some highs too.

Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 06:28:17 PM
I like the term "waggler".  As far as extra cost and size, it could possibly be done with a few extra op amps and a small handful of resistors/caps* (maybe. I'd have to look into it more seriously.  Some relatively cheap off the shelf stuff might even do everything for you, but you wouldn't want anything designed to expect, and consequently attempt to "clean up", digital pulses...  ).

*I confess that I mainly build for myself, so I tend to build toward complexity, cost be damned.  :icon_wink:
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 06:43:36 PM
At this point, a lower-tech improvement might be useful.

Try creating a hood for you sensor, a small short tube to block some of the ambient light from the periphery.   :icon_wink:
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 07:35:21 PM
I'll throw this in:
http://electronics.stackexchange.com/questions/24897/how-to-make-ir-proximity-detector-immune-to-the-daylight
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 16, 2017, 08:29:19 PM
Quote from: Kipper4 on March 16, 2017, 06:04:45 PM
I guess it might depend also on if a single waggler could be used to do both processes too.
Almost.  It's essentially the same process each way, but both would need to be done at the same time.  You could reuse the carrier generator part for both, so there is a bit of savings. 

[Ignore this -- purely academic]
If it gets too crazy, you could go all the way sophisticated and use a time-of-flight sensor and a small microcontroller (honestly, that's how I'd do it, but mostly because it appeals to my particular building tastes, so I would find the experience rewarding enough to offset the cost....).  Probably looking at ~$25 USD (~£20 GBP) for the sensor and microcontroller.
[/Ignore this -- purely academic]
Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on March 17, 2017, 05:50:56 AM
We've almost been here before...
http://www.diystompboxes.com/smfforum/index.php?topic=29515.0

I can't help thinking if you want simple then...
Use a filter over the sensors. The white-ish plastic window over IR alarm detectors is doing 2 things - focus a wide angle into the sensor AND filter the received radiation to a narrower band of wavelength.

And/or...
As I mentioned earlier, use a differential detector.
https://learn.adafruit.com/pir-passive-infrared-proximity-motion-sensor/how-pirs-work
... honestly, I had nothing to do with the Dragon in the diagram. Actually, there are different versions of the same diagram all over the place with a different beast walking by...
(http://www.glolab.com/pirparts/infrared_files/image002.jpg)
So anyway, there are 2 sensors in the device that are wired in opposite polarity. Like a Figure-8 microphone, they can't see in the middle - everything they receive in common gets cancelled out. But they do see either side of the middle.
It may be possible to arrange things so this is useful.
If reflection from the transmitter will mostly fall on one sensor, then it will be largely immune to ambient that is reaching both sensors.

Add that this gets away from photo-diodes, which can see too much visible light. And don't forget that IR is essentially radiated heat. In the PIR sensor, you could probably just mask over one half of its window with tape or something - the covered sensor will still "see" the ambient heat.
(https://cdn-learn.adafruit.com/assets/assets/000/000/512/medium800/proximity_pyrosensor.gif?1447975942)



Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 17, 2017, 08:13:16 AM
Quotehonestly, I had nothing to do with the Dragon in the diagram.
I thought that was a reindeer/duck hybrid.   :icon_smile:
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 17, 2017, 08:24:13 AM

So its Not like this.
The leds in the diagram ARE as Eric says orientated wrong

(http://i.imgur.com/DSaY6DP.png)

Thanks guys
Demo on the way.

btw If you build the tremolo use a non polar charge cap 1uf.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 17, 2017, 08:27:54 AM
https://youtu.be/i5hdmKs6VIo
Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on March 17, 2017, 09:05:11 AM
I meant the diagram in the link. See ... I know nobody bothers to follow links, which I why I found the one with deer.
(https://cdn-learn.adafruit.com/assets/assets/000/035/647/medium640/proximity_pir-diagram.png?1473477850)
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 17, 2017, 09:11:04 AM
Quote from: anotherjim on March 17, 2017, 05:50:56 AM
We've almost been here before...
http://www.diystompboxes.com/smfforum/index.php?topic=29515.0
In a different thread, Paul Perry said he used a 555 timer to modulate the transmitter IRED at about 200kHz (in his commercial Spacebeam theramin).  Sounds like a great simple solution to that part of the problem. 

The nice part is (I over thought it before), there is nothing to modulate on the transmitter side.  Just make a square wave with the 555 and you are done.  You can demodulate at the receiver by simply filtering and rectifying.  It turns out that would be cheap and easy after all.   :icon_biggrin:
Title: Re: calling all Car and Tractor specialist
Post by: duck_arse on March 17, 2017, 10:14:27 AM
CLR's - noted!

QuoteI thought that was a reindeer/duck hybrid.

interesting.

also, I'd have thort the easiest way to make the receiver less ambient sensitive would be to put an IR filter over it, like the one on the front of all those busted remote controls you have.
Title: Re: calling all Car and Tractor specialist
Post by: anotherjim on March 17, 2017, 10:26:17 AM
Eric, if you pulse the source at some hz, do you need to band pass the receiver, or should it be sufficient to AC couple and get the envelope. The Ultrasonic system is that way by default - it wont send without running at the right hz. Receivers don't need to filter, because they already are tuned to that frequency. However they assume there's nothing else transmitting nearby at similar hz that could confuse it.
Title: Re: calling all Car and Tractor specialist
Post by: Kipper4 on March 17, 2017, 11:16:24 AM
Another thing to note is that a black snoot worked better than a white one in my ghetto test.
Title: Re: calling all Car and Tractor specialist
Post by: EBK on March 17, 2017, 11:18:11 AM
Quote from: anotherjim on March 17, 2017, 10:26:17 AM
Eric, if you pulse the source at some hz, do you need to band pass the receiver, or should it be sufficient to AC couple and get the envelope. The Ultrasonic system is that way by default - it wont send without running at the right hz. Receivers don't need to filter, because they already are tuned to that frequency. However they assume there's nothing else transmitting nearby at similar hz that could confuse it.
In this case, the filtering is the tuning.
Yes, I'd use a bandpass filter here.

AC coupling and taking the envelope is essentially the idea, but it probably wouldn't hurt to AC couple with a high pass cutoff above the audible frequencies.  If we don't want to make too many assumptions about the spectral composition of the background IR, we can use a bandpass filter to simply get rid of as much potential noise as possible.  Plus, it's usually (always?) a good idea to cut off the frequencies above what we're interested in.