Let's Make Robots!

"Jar of FireFlies" - 08 picaxe LM324 opamp Syncronisation

Here is FireFly C10 detecting the UV glowing light off FireFly C224

C10 then synchronises and flashes in unison with C224

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I like the range you're getting on the detection. I too wonder if a photodiode/transistor tuned into the wavelength would be more sensitive. I was going to simulate the glow of luciferase with my electrobugs and had found LEDs in the 560nm range. I'd also sourced out a phototransistor that is most sensitive in the 560nm spectrum. I was hoping they would pair well together.

I'm curious that the UV LEDs are more sensitive than normal LEDs (especially blue or green) as I'd guess most of the UV energy was consumed exciting the fluorescing molecules around their lenses. But that's just what was banging around inside my walnut brain.

The UV LEDs are probably more expensive because they are relatively new. Blue LEDs were very expensive when they first come out but have dropped a lot in price now.

.... however inexpensive ones like mine are not 100% pure as you can see - from what i can gather its the plastic encapsulation material that is the problem - it flouresses!! if it contains impurities .... for my application, its a true advantage.

Great work!  I posted on your other entry and see that you have answered my question.

So the photoresistor is catching the flashes/glow from the blue fly? Could you replace the caps/eyes with two small photoresistors, giving him actual functional eyes?

Yes the blue firefly is the master .... and the green firefly is the slave that waits and lights up in synchro.

You got me thinking......Doubling up the photo-resistor tweaked slightly left and right will give a better detect sphere (better than single line of site.

The range is 20cm/8inches at moment - this is with the blue version - the green version gives out a brighter flash....

I wonder what kind of range you would get with UV LEDs acting as detectors instead of the photoresistors.

 Yes I have tested UV Led as detector.... and i have to say, with simple multimeter test UV leds detect better than normal leds - however i have  to "pling" a suitable led detect circuit from my cortex.

Something like this?

The UV LEDs should be most sensitive as detectors to the wavelength of light they emit. So you might even get better range.