I'm working on a project inspired by the pulse-like stick-slip motion of a creaking hardwood floor.
I plan to use a force-sensing resistor as part of an actuator. As force is applied to the FSR, pulses will be generated as the resistance changes through discrete steps. These pulses will control some sort of audio switching, either as on/off or as A/B switching (probably cross-fading).
I have no idea if this will be musically useful when I'm done, but as I've established time and time again, I have more fun with impractical ideas anyway. :icon_razz:
Here is where I am at so far:
(http://i.imgur.com/lFL66XKl.jpg)
The disc sticking up is my FSR (from smallbear). The IC is a LM3914* dot/bar LED display driver operating in dot mode. The LEDs light up sequentially (with a small bit of overlap) as force is applied to the FSR (no LEDs are lit when at zero force, and the last LED stays lit at max force).
I next plan to divide the LED output lines (these are current sinks) into even and odd groups, each group going into a separate op amp, i.e., outputs 1, 3, 5, 7, and 9 will form the odd group and outputs 2, 4, 6, 8, and 10 will form the even group. If all goes well, the two op amps should produce slightly overlapping complementary pulse signals. I could simply take just the odd outputs and use only one op amp, I suppose, but I'd miss out on the overlap, which might be useful.
Anyway, this is still pretty early in development, but I welcome any thoughts or opinions.
*The LM3914 happened to already be in my parts bin. As far as I know, it is no longer produced in DIP form but is still available in a PLCC. If I didn't already have this chip, I might have considered using a microcontroller instead.
Edit: smallbear still has some LM3914 DIPs.
Edit 2: I actually won't need the op amps I mentioned. A simpler BJT circuit will do just fine. More on this later.
Also, part of the motivation behind this project is that I want to see if I can combine an FSR with this actuator:
(https://cdn10.bigcommerce.com/s-sxoup5r/products/3254/images/4258/actuator__78832.1409778534.220.220.jpg)
The actuator has a metal rod connected to the spring. I plan to place a metal disc (perhaps a coin) on top of the FSR and have this spring/rod push down on that.
Quote from: EBK on January 25, 2019, 09:12:58 AM
I'm working on a project inspired by the pulse-like stick-slip motion of a creaking hardwood floor.
Wanna buy my house?
What did I just read ?
I'm gonna have to reread when I'm sober.
Maybe cross fading might be easier to implement with electric druids cross fader and the fsr as part of a voltage divider in lieu of the pot.
Quote from: Kipper4 on January 25, 2019, 12:22:56 PM
What did I just read ?
I'm gonna have to reread when I'm sober.
The short summary:
1. You step on a force sensor.
2. Up to 5 pulses are generated. The number and timing of the pulses depends on how much force you apply and how quickly you apply it.
3. The pulses will be used to switch some audio signals back and forth, like a multiplexer.
Maybe I can help! Here's MY house! :) Need a creaky floor??? It's a neat idea, definitely original, I've NEVER seen anything like it; it'll be cool to see where you go with it!
(https://i.imgur.com/7ZxFX6w.jpg)
Multiplexer? Edit. I googled it. Got it
Sorry to be a nuisance.
I'm loving it anyway.
It's giving me ideas.
Thanks Eric
Quote from: GibsonGM on January 25, 2019, 01:28:04 PM
(https://i.postimg.cc/85KSGhS6/7ZxFX6w.jpg)
Bastard in a basket!
HEY! That's my grandfather!!
Actually, no...those are the remaining civil war veterans in my area in 1895 at my then 30 yr old house, which was also the school up here. Grand Army of the Republic reunion. I tell my wife they talk to me when I'm down in the cellar. The guy on the far right looks like Col. Henry Blake from MASH.
This is off-topic; I'll stop ;)
Quote from: GibsonGM on January 25, 2019, 06:50:11 PM
This is off-topic; I'll stop ;)
I'll allow it. The house has creaky floors, so it's relevant enough. :icon_wink:
I should've used quotation marks. It was a movie reference. Dude looks like Daniel Day Lewis in There Will Be Blood.
You know - he really does! And Henry Blake, too...
Needs more fishing lures. Idle hands are the devil's.....oh, too late.
Oh how I would love to live in a world where this was literally true:
QuoteThere is nothing worse than tiptoeing around your home while people are asleep and hearing a harmony of squeaking floorboards.
:icon_rolleyes:
(from https://www.411homerepair.com/diy/floors-tile-hardwood/10055-What-Causes-Creaky-Floorboards.html)
You do get used to it; doesn't bother me, and I don't try to avoid the spots. She's used to it.
Up here, the wind is the worst noise-maker!
Preliminary schematic of the FSR pulse generator circuit:
(http://i.imgur.com/O9JNonXl.jpg)
Some of the unlabeled resistors I've already worked out, but I need to look back at my notes for the values. The diodes are LEDs, but I just didn't draw the arrows out of laziness. :icon_wink:
P1 and P2 are the complementary pulse outputs.
Surprisingly low parts count (surprising to me, anyway). The LM3914 is a pretty cool chip.
I need to see if I can scrounge up two vactrols. I have an idea that may simplify this thing even more and get me closer to a demo that makes some sound happen.
I'm thinking I can replace those two top resistors with the vactrol LEDs, and get rid of the BJTs.
I love where this is going, bravo.
I made an arduino theremin with ping location sensors but instead of a fluid pitch portomento it was in "zones" that triggered samples. Like a drum machine you play in the air instead of pads. Fun stuff sensors are!
Quote from: garcho on January 27, 2019, 12:13:52 PM
I love where this is going, bravo.
I made an arduino theremin with ping location sensors but instead of a fluid pitch portomento it was in "zones" that triggered samples. Like a drum machine you play in the air instead of pads. Fun stuff sensors are!
Thanks! Fun stuff, indeed.
I've replaced the BJT/resistor stuff at the top of the schematic with two LEDs and recorded a quick visual demo (I'll update the schematic later):
I built a quick version of the single vactrol circuit last night (I found two NSL-32 vactrols in my parts collection):
(http://i.imgur.com/oetHBUml.jpg)
The results were so encouraging that I tore it apart to proceed with the two vactrol version without bothering to record a sound demo (I'll be able to make the same sound in the two vactrol version by leaving the return jack disconnected). :icon_razz:
The sound was reminiscent of the trick of rapidly toggling a pickup selector switch to cut the sound in and out.
The updated FSR pulse generator circuit schematic (MUCH simpler), with resistor values added:
(http://i.imgur.com/i2P2VUIl.jpg)
I'll sketch up the other half a bit later.
Here is the other half of the circuit as it exists on my breadboard:
(http://i.imgur.com/V7g40wGl.jpg)
Edit: I need to redraw this so it doesn't look so weird with how the send/return jacks are placed. :icon_wink:
Here is a more logical arrangement of the same schematic:
(http://i.imgur.com/Ok450JVl.jpg)
It works, and it is pretty interesting. Hopefully, I'll be able to record a demo with sound soon. To quickly test it, I ran clean guitar into the input and hooked a tubescreamer at max gain through the send/return loop. :icon_twisted:
One quirk that I will have to think more about is that, with no force applied to the FSR, no LEDs are lit, and thus, no signal comes out. This may be useful in some circumstances, so I may implement a toggle switch that optionally "corrects" this.
The thing that excites me the most about this project is that I finally get to share something new and original (as far as I know, anyway) with the community. :icon_cool:
Here's a demo with some sound. I apologize for the low volume (didn't want to wake up my family). In this video, I have the send/return loop connected to my mutron iii envelope filter, which gives this thing some cool trippy results. :icon_biggrin:
https://youtu.be/fXE0LhsIjqE
And here is one more demo, with a tube screamer this time:
https://youtu.be/2ceN_CLJLpU
Next, I need to tackle lining up the FSR underneath this (with something in between to protect the FSR and distribute the force across its surface):
(http://i.imgur.com/YY37MFTl.jpg)
Once I do that, I can try playing a guitar with both hands while controlling this circuit to see if there might be musical potential in this wacky idea.
That actuator is avalable from smallbear:
http://smallbear-electronics.mybigcommerce.com/switch-actuator-for-b-o-b/
I got the FSR there too, by the way:
http://smallbear-electronics.mybigcommerce.com/alpha-membrane-force-sensor-mf-01/
Looks like the space between the actuator's external spring and the lid of the enclosure is pretty close to $2 USD (in US quarters) or 14mm.
(http://i.imgur.com/13CrtRol.jpg)
very cool, DIY "mash" switching, eat yer hearts out TC Elec
Quote from: garcho on January 30, 2019, 11:30:24 AM
very cool, DIY "mash" switching, eat yer hearts out TC Elec
Wanna know the best part?
It works!
I'll have to add up the amount of change I used in the end. :icon_razz: Edit: Eight US quarters, with the FSR sandwiched between the top two.
More importantly though, an extra secret ingredient was required to get it working. When I squeezed the FSR between my fingers, it worked perfectly. When I squeezed it between two coins? Nothing! What was needed? Some blu tack. I put some of that on each side of the FSR, and it worked.
More demos soon! :icon_cool:
Quote from: EBK on January 30, 2019, 12:18:49 PM
When I squeezed it between two coins? Nothing! What was needed? Some blu tack.
I'm guessing your coins were shorting out the FSR? But repeated squishing of blutac will make it thinner and thinner, until...
I'd use a simple piece of paper. Or a dollar bill. :D
It appeared to be the opposite problem. I theorize that, by being so rigid, the coins only contacted the FSR properly over a small surface area (due to the relief in the images on the coin faces). The result was nearly no change in resistance from the zero-force high resistance. The blu tack filled in the spaces, allowing more uniform pressure.
The spring on the actuator is getting a bit out of shape from freely sliding around on top of the stack of quarters.
(http://i.imgur.com/9snkM3Am.jpg)
To solve this, I've decided to dig out my manual 3D printer: JB Weld and miscellaneous hardware. :icon_razz:
(http://i.imgur.com/SNd6y71m.jpg)
(http://i.imgur.com/8w6c6cim.jpg)
With blu-tack and JB weld in there, it really needs duct-tape now for the cob-jobprototype trifecta.
Nice!
You can also try plastic or hot glue (just a drop on a surface, let it harden) washers. Blu tack would slowly creep out with repeated presses.
Quote from: highwater on February 02, 2019, 01:59:14 AM
With blu-tack and JB weld in there, it really needs duct-tape now for the cob-jobprototype trifecta.
The stack of quarters is held together and attached to the lid using gaffers tape (seriously). :icon_cool: :icon_lol:
Quote from: marcelomd on February 02, 2019, 06:04:11 AM
Nice!
You can also try plastic or hot glue (just a drop on a surface, let it harden) washers. Blu tack would slowly creep out with repeated presses.
I might try to find some rubber gasket material next.
as R.G. might say, "mouse pad, cobber!"
Quote from: duck_arse on February 02, 2019, 09:00:07 AM
as R.G. might say, "mouse pad, cobber!"
Maybe if I can find one of those super thin ones....
I'm thinking jar lid gripper at the moment.
I found a thin mousepad in my office, and I cut some circles out of it for testing.
(http://i.imgur.com/2oaYJQDl.jpg)
If this works, it would save me $0.75 because the two pad discs (when uncompressed) are the same thickness as three quarters. :icon_razz:
I was going to suggest neoprene. Time to hack that gimp suit up Eric :)
Or maybe some rubber 1/2" tap washers.
Ok, preliminary results suggest the mousepad is too soft....
The actuator has a very limited travel distance to go from minimum to maximum loading force. The mousepad couldn't even deliver the amount of force needed to light the first LED. I need something that more closely approximates a thin layer of blu tack. My present thought, based on my observations of the extent that the blu tack spread out, is that blu tack is in the lead.
- Folded-up aluminum foil
- Electrical tape
- Guitar pick(s)
I'm going to redo the mousepad experiment. I think I missed something....
Also, I need to try with smaller discs. The sensor is about the size of a dime, but the pads are the size of a quarter, which is affecting things. Sorry I can't convert these measurements to more international round-thing units off the top of my head. :icon_razz:
Ok. Verified that the mousepad is too soft, unless I wanted to figure out how to more directly couple the actuator to it (but then the travel distance and feel could get messed up).
I'm wondering, however, if I can approach this problem more scientifically....
Can I make a custom spring out of, say, a guitar string?
https://www.acxesspring.com/espanol/spring-constant-calculator.html
I can measure the travel distance of the actuator easily enough. And, I can use my kitchen scale to figure out the necessary force to light the LEDs.
Maybe....
Before I go there though, I'm going to simply try some guitar pick shims with the existing spring.
I've decided to blow the thick layer of dust off of this old project.
I have moved the circuit from my breadboard to a piece of veroboard and verified that it still works.
(https://i.imgur.com/imrsbxul.jpg)
I may post another demo video of the circuit sometime (last night, I had a guitar synth pedal in the send/return loop, which was wild, glitchy madness :icon_twisted:). Otherwise, I'm left with trying to figure out how to box it up (which is always the hardest part for me).
In case there is some mild interest in this project or in the force sensitive resistor actuator, I'm posting some hardware progress:
(https://i.imgur.com/xKhtu1Ol.jpg)
The wood is mounted like a diving board with a piece of pick guard as a spacer:
(https://i.imgur.com/tiW4ffql.jpg)
The FSR gets tucked underneath that overhanging bit, with a small disc of foam tape on top of it. I've also glued a piece of aluminum flashing to the underside of the wood to reinforce it a bit.
The toggle and hole are for a trimmer that simply adds some resistance in parallel with the FSR to reduce the effective maximum resistance until the first LED lights up with no foot pressure applied. Without this, the circuit acts basically as a kill switch when your foot is off of it, which might be useful in some contexts (hence the toggle).
It seems to work rather well, but a better demo video will have to wait until I move everything into the enclosure.
and does the plank actually creak?
Quote from: duck_arse on July 02, 2020, 10:27:01 AM
and does the plank actually creak?
Creaky wood piece? :D
Nice enclosure...
Quote from: duck_arse on July 02, 2020, 10:27:01 AM
and does the plank actually creak?
If I loosen the bolts, it might. :icon_wink:
The slight deflection as I step on it does at least "feel" a little like a loose, creaky floorboard, which was my goal. I'll leave it to the circuit to make all the creaky sounds.
you can outfit someone's foley studio
bravo, cool project
Quote from: EBK on January 28, 2019, 10:26:23 PM
Here's a demo with some sound. I apologize for the low volume (didn't want to wake up my family). In this video, I have the send/return loop connected to my mutron iii envelope filter, which gives this thing some cool trippy results. :icon_biggrin:
https://youtu.be/fXE0LhsIjqE
Any updates on this project? Sounds like something I'd hear on a Renaldo and the Loaf album. :icon_cool:
I should probably bump this back up to the top of the queue. The only thing left is running a ton of wires because I didn't have the foresight to place the bar graph module in its final location when I designed the vero layout. :icon_rolleyes: For this prototype, I'm actually going to use wire wrap construction to hook that up. It's going to look quite clumsy inside, which is probably why I lost my momentum.
(https://i.imgur.com/Utb5TV5l.jpg)
This is way cool! 8)
Looks like I forgot to post my vero layout earlier.
(https://i.imgur.com/5NQq2ej.jpg)
Blowing the dust off of this again.
Did lots of wiring and soldering.
(https://i.imgur.com/ZEXBCr2l.jpg)
I'm hoping this still works. Will test it tonight.
Cool. Loving the quantum computer in the top-left. :icon_cool:
Quote from: bluebunny on October 07, 2021, 04:13:05 AM
Cool. Loving the quantum computer in the top-left. :icon_cool:
Yeah, that's the result of sloppy planning. I created the layout with the bar graph top center, but I needed to move it after I built the board. Not too many pedals with wire wrap, I imagine. :icon_razz:
It's nice to see some wire-wrapping being done, and very tidy it looks too!
I was in Japan a few years back and visited a very old home where the floors were made to be intentionally squeaky to act as a form of burglar alarm should anyone attempt to gain entry in the middle of the night. The squeaks sounded almost like chirping birds :o
regards, Jack
I can't even remember what the pedal is meant to do. as it happens, I've been cutting-up a floorboard for a noisemaker front panel of late.
Quote from: duck_arse on October 07, 2021, 09:35:48 AM
I can't even remember what the pedal is meant to do.
In a nutshell, the output is switched back and forth several times between two input signals as you apply force with your foot. If you think of a real creaky floor board, you can make it creak slowly or quickly, depending on how you apply your weight. The switching in the pedal is the same way.
Quote from: amz-fx on October 07, 2021, 09:24:51 AM
I was in Japan a few years back and visited a very old home where the floors were made to be intentionally squeaky to act as a form of burglar alarm should anyone attempt to gain entry in the middle of the night. The squeaks sounded almost like chirping birds :o
A friend of mine had the whole of his front garden covered in gravel for the same reason. Then complained when I walked small sharp stones onto his pristine wooden floors... :icon_rolleyes:
Quote from: duck_arse on October 07, 2021, 09:35:48 AM
... I've been cutting-up a floorboard for a noisemaker front panel of late.
And you covered the hole with a rug, right?)
Quote from: bluebunny on October 07, 2021, 11:13:05 AM
A friend of mine had the whole of his front garden covered in gravel for the same reason. Then complained when I walked small sharp stones onto his pristine wooden floors... :icon_rolleyes:
So next time you hop over there - go barefoot. Then they'll complain about the blood...
Quote from: amz-fx on October 07, 2021, 09:24:51 AM
I was in Japan a few years back and visited a very old home where the floors were made to be intentionally squeaky to act as a form of burglar alarm should anyone attempt to gain entry in the middle of the night. The squeaks sounded almost like chirping birds :o
regards, Jack
From Wikipedia:
QuoteNightingale floors (鴬張り or 鶯張り, uguisubari) About this soundlisten (help·info) are floors that make a chirping sound when walked upon. These floors were used in the hallways of some temples and palaces, the most famous example being Nijō Castle, in Kyoto, Japan. Dry boards naturally creak under pressure, but these floors were built in a way that the flooring nails rub against a jacket or clamp, causing chirping noises. It is unclear if the design was intentional. It seems that, at least initially, the effect arose by chance. An information sign in Nijō castle states that "The singing sound is not actually intentional, stemming rather from the movement of nails against clumps in the floor caused by wear and tear over the years". Legend has it that the squeaking floors were used as a security device, assuring that none could sneak through the corridors undetected.
Quote from: bluebunny on October 07, 2021, 11:13:05 AMA friend of mine had the whole of his front garden covered in gravel for the same reason. Then complained when I walked small sharp stones onto his pristine wooden floors... :icon_rolleyes:
School I used to work for did it different. The back garden was "carpeted" in round river-stones. Ideal for breaking into office windows.
A few blinking lights deterred the vandals for a few years.
Dropping a note here, mostly for myself:
I need to add the trim components to the schematic. It is a 10k trimpot in series with a 2.7k fixed resistor and a toggle switch. This entire combination is placed in parallel with the FSR. When connected by the toggle, it reduces the effective resistance of the FSR when no force is applied. For the circuit, this mimics the condition where a bit of force is applied. Adjustable from (basically) none to enough to light the second bar.
When no bars are lit, there is no audio output. When the first bar is lit, the output is a buffered version of the pedal input. When the second bar is lit, the output is buffered version of the return jack signal.
Edit: cleaner schematic.
(https://i.imgur.com/5EiYnl9h.jpeg)
A quick and crude demo with a clean input and a noisy fuzz connected to the send/return (yes, I know. I buffered a fuzz... :icon_rolleyes:). It shows that the pedal works. I'll make music with it later.
If you missed the description of how this works:
Think of the LED bars as being numbered from 1 to 10, top to bottom. When an odd bar is lit, you hear the input jack signal. When an even bar is lit, you hear the return jack signal. The bar graph also serves as a force meter.
(https://st.focusedcollection.com/11312302/i/650/focused_149185316-stock-photo-grilled-sausage-on-fork.jpg)
Quote from: bluebunny on October 09, 2021, 06:28:59 AM
(https://st.focusedcollection.com/11312302/i/650/focused_149185316-stock-photo-grilled-sausage-on-fork.jpg)
what does the bargraph on the sausage indicate/quantify?
Quote from: duck_arse on October 09, 2021, 08:35:51 AM
what does the bargraph on the sausage indicate/quantify?
Ten scorch marks = I think Eric has his full weight on it.
That demo video is also a demo of my Cuban cigar box amp, by the way (as picked up by my tiny cell phone mic and compressed by my phone and YouTube :icon_razz:).
Some more fun noises, this time with a flanger:
For completeness, here is the Creaky Floor by itself, with nothing plugged into the send/return jacks:
The socks sound just like the shoes.
I started to record one barefoot, but decided against it. :icon_razz:
Quote from: EBK on October 13, 2021, 04:23:24 PM
I started to record one barefoot, but decided against it. :icon_razz:
Will your toenails grow back after you made picks out of them?
Yes, but I'm still keeping my socks on. :icon_razz:
Minor update: I cleaned up the schematic above (https://www.diystompboxes.com/smfforum/index.php?topic=121805.msg1230507#msg1230507).
I was just directed to this project, and Whoa!!! very interesting!!!
EBK; You have exactly 14 days to get this done before Halloweeeeeen.
(I was going to say your pedal stinks but see it might not be the pedal after all)
I think the only thing more I would do with this prototype is laser a new piece of wood with some labels. This is my draft. Nothing fancy.
(https://i.imgur.com/Raf2dxFl.jpg)
I'm quite happy with it as it is though. I don't want to add a bypass switch. If you set the trim at the first LED, it is basically in buffered bypass already.
Quote from: Phend on October 17, 2021, 04:12:06 PM
(I was going to say your pedal stinks but see it might not be the pedal after all)
Hey! Those are clean socks in those demos, I swear! :icon_razz:
I made a bezel for the lights out of some 1/16-in. plywood. It's a slight step up from the last time I made a bar graph bezel out of an old floppy disk.
(https://i.imgur.com/b7ztJa3m.jpeg)
Very neat, Eric. I see you've gone for a Scandinavian laminate flooring look. I think it would be cool to do another with a 18th century tavern oak floorboard vibe. :icon_cool:
I recorded a demo last night that shows the trim adjustment. A Rat pedal is connected to the send/return jacks in the video.
Trim off: No signal when my foot is lifted.
Trim on, second LED lit: The Rat output is heard when my foot is lifted.
Trim on, first LED lit: The clean signal is heard when my foot is lifted.
I love this project. This thing is so neato!
Thanks! :icon_smile: