Let's Make Robots!

Megan40 - Picaxe 08 Firefly

Attracts FireFlies into your garden

This is robotic Firefly based on a picaxe 08 using UltraViolet leds as sensors.

Flight School.

Here you can see her Big Flattering Stereo eyes, they are simply UltraViolet LEDs - the red leds on top are feedback indicators.

The UV leds are connected to a LM324 opamp that amplifies and also conditions the logic and trip levels going into the picaxe.

I can highly recommend the use of Ultra Violet leds as detectors as they are not affected by ambient /infrared and laser light.

Her rear is composed of a Spiraled Glow PolyMorph tube - it is illuminated by two UV leds.

Flashing good time was had by all......

The little 8 pin chip is its tiny picaxe 08 brain....... inclusive 128 byte memory.

Flashing routines and UV tracking routines fitted noproblemo (the faster you write your code the more you can fit in).

Here you can see her 40MΩ (in total) opamp feedback resistors - although 230MΩ was recommended (yikkeess Air-Gap has less).

Megan40 is attached to the top of a glass jar via a spring to a servo, this gives her life and enables her to track & follow my UV pen light or UV laser. She is sitting on my window-sill enjoying the sun - but eagerly awaits a tickling from my UV probe.......

Yes she is green powered by 2 solarcells float - trickle charging 4 AA recharge batteries

What is Megan40s future :-

I plan to use her eyes as an input program select , ie on "start up" by shining the UV into here right eye...she will go into tracking mode. Or if left eye is chosen then she will go into autonomous mode and act like a firefly attracting real fireflies intomy garden.

NB. UVA-UVB-UVC are all to be treated with care. High level/Overexposure is hazardous to health.

Or if two eyes are chosen ............ who knows..... what would you expect her to do .....?

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You almost had me believing the servo was controled without wires. Hires pics reveal your secret illusionist's wires.

Great work on the sci-fi-flies G!

Truth is rik , i did not know until i switched on the supply whether the current flowing through the ultra thin transformer windings would burn out...... just hope she does not stall her servo, else there will be more than just a flash.

Hey Gareth just a question ,

Isn't UV light bad for humans eyes?

True UltraViolet light has to treated with care ....

An overexposure to UVA-UVB-UVC radiation can cause sunburn and some forms of skin cancer.

From what i have checked, the UV LEDs i use only just lean into the UVA  ie more visible violet end of spectrum.

(True UV is not visible to human eye)

Anyways care has to be taken as they can give temporary  "Arc-Eye" .....as with any bright light source, should you happen to look directly into the led.

Sunglasses are recommended to filter out UV.

Hinwise :- Even InfraRed (strong levels,or pulsed) are hazodous to health.

NB :- Please correct me if any of the above is incorrect - as UV is new to me too.



I believe you are wrong about IR...

I don't know if it can be bad for health in some situations, but i'm sure infrared is used in many areas to improve health.

IR light will not blind you in the same moment you are being exposed to it but if you are exposed to it for a long period 

I think then it will be harmfull for your eyes and can blind you.

Years ago, (1970s) I worked with EPROMs (as opposed to EEPROMs, which are electrically reprogrammable). EPROMs have a round glass window in the top of the chip. You erase them by putting them under UV light at a certain frequency (253.7 nanometers or 2537 Å /angstroms).

I built my own computer from scratch and wrote the programming, so every time I made a correction or adjustment to the program, I had to reburn the 2716 EPROMs and thus needed a UV light at the right frequency.

The Point:  To get a light in that range I had to go to a hospital supply and buy a "germicidal" lamp.  UV in the 2540 Å range is used in hospitals to kill germs. It also kills other living organisms such as human cells.  There is a warning right on the light bulb that exposure to the light even for a few minutes is dangerous to humans and WILL cause skin cancers, etc. I took extra precautions to not be exposed to the UV radiation while erasing chips. (I put the lamp with the UV bulb in my photographic darkroom (another hobby back then) and trailed the cord out the door, only plugging it in with the room door closed.)

Oh and that was a 15 watt flourescent, so not super bright or anything, ---So, yes, at the right frequencies, UV is dangerous.


Wohowwww looks like you where into the deep dangerous end of UV, my LEDs are well down the other end.....

Yes i used the 8K Eproms too - Aka Nascom1+2 firmware .... plus various other work related projects... Long time since i used one now. I can remember that after erasing 20-30 minutes the logic levels would be cooked to logic 1 ( you would have to run test program afterwards to confirm it was actually fully erased)

BTW :- Early RAM chips also had a glass windows in them (however ....masked black) ....... some curious people removed the mask (errr me too) and discovered CCD cameras.

haha, great idea. I was chasing fireflies all the time when they came out and wonder if you could mimik the light code with this one...maybe a pretty firefly girl or a bunch of them will come to your guy to mate with him ;-)))