Has anyone tried triggering the LED with a triangle wave yet?  I'm about to try that, with the schem I got from play-hookey.com

i'll post how it comes out... (if it works)

actually...i cant get it working .  All I get out of the op-amp is linear voltage....here's the link.
http://www.play-hookey.com/analog/triangle_waveform_generator.html
how can I mess that up?

I haven't really gotten anything with op-amps to work.  I think my problem is providing them power.  I've heard you need voltage halfing circuits or something...  True? I've just been connecting Vcc to the + on the battery and V- to ground.  I'm using a TL072.

Thanks.

Quote from: HalHas anyone tried triggering the LED with a triangle wave yet?  I'm about to try that, with the schem I got from play-hookey.com

i'll post how it comes out... (if it works)

hmm i havent'. sorry,  i just packaged up two of them and sold them

Quote from: Halactually...i cant get it working .  All I get out of the op-amp is linear voltage....here's the link.
http://www.play-hookey.com/analog/triangle_waveform_generator.html
how can I mess that up?

I haven't really gotten anything with op-amps to work.  I think my problem is providing them power.  I've heard you need voltage halfing circuits or something...  True? I've just been connecting Vcc to the + on the battery and V- to ground.  I'm using a TL072.

Thanks.

If you're going to connect the V- from the op amp to ground, you're going to need a Vref in there at 4.5v.  Try connecting a 10k resistor from ground, a 10k from your V+, and a 10uf cap from ground all to one point and you should get a near perfect half of your voltage.  Now, that's what you use as ground in terms of the op amp.

Here's a schematic I did of a very similiar design:



That includes the vref schem.  Hope that helps!  

-Colin