Small Insect Traffic Sensors with SMD LEDs

Hi! Been working on this project for a decade in various forms on and off, but essentially, I want very small cheap sensors that we can place all over a tree and monitor the insect traffic at multple points (and hopefully multiple trees). I’ve tried a bunch of funky techniques over the years, Graphene+Silly Putty pressure sensors, Optical Mouse cameras, etc…
Recently been having some luck with dense arrays of SMD LEDs (More descriptions below). I know folks like Urs know all kinds of cool shit about SMD LEDs, so figure folks might have good advice or be interested!

i am putting project files at this github

I am also kicking off development by leading an interactive art + design workshop at pifcamp (a slovenian hacker camp in the alps ) . Because it is plague times, they are sharing free workshops and talks all week long! You can just register at pif . camp

for instance tomorrow (Aug 4) at 10am panama time, we are doing a workshop about making tiny ant sensors from SMD LEDs. Please join if you are interested!

we are reverse-biasing some LED’s to use as sensors to monitor the ants (Forrest Sims method). Now usually this lets you sense changes in light with an LED, but in generally pretty crapily. LEDs as sensors are usually not that sensitive compared to things like photoresistors or photo diodes. But on a whim, i tried it with some red SMD LEDs that i was going to use for the workshop (and since the SMD leds are so small even if they were poor detectors, they could still be more “Ant Sized” and useful as simple photo gates in an ant farm or something).

Turns out the SMD LED’s seem QUITE sensitive, and can pick up changes in light even obliquely.

The bonus part is that each sensor can function as an LED as well. So you can very easily (and SUPER CHEAPLY) make modulated light sampling arrays of these.

You can take one LED in the array, turn it on. Then all other LEDs sense the light from that particular LED. Next choose a different LED from the array and sample. Now you have the ability to tell small differences in light that might occur from light hitting an ant at many different angles. Finally compare all these readings to a sample where NO LED’s are lit up, and you have a very sensitive sensor that is somewhat ambient light independent. You can even take a sample with ALL other LEDs lit up too!

All the code for doing this on an Arduino is all on our GitHub posted above.

The best part is the hardware is super cheap, and if i make PCB’s and have them made they are pretty simple, and can get pretty compact. Next i want to toss in a multiplexer and make sure this method still works, and crank up the number of SMD leds. Eventually will want to try with IR SMD leds.

BTW we are using RED leds because A) They seem more sensitive than other colors, B) many invertebrates and ants often have a hard time seeing longer wavelength, so hopefully it bothers them less C) We can still see them so it makes debugging easier.

I also am putting some 3D models for tube sensor attachments and ant farms in that github too.

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also here’s a preview of some of the success we have had so far with SMD LEDs!


we are also in the middle of our SGMK Homemade summer-camp here!

and i just started to work on this ant-farm in a CD-case…

And put some LEDs and Attiny85 around. stay tuned…