Let's Make Robots!

MediBot - My First Photovore


This represents my first attempt at any robot. Not the happy ending that I expected. Even after two tries still nothing. I followed the tutorial found here :--> http://www.geocities.com/SouthBeach/6897/photovore.html  . I checked everything i could i even used a smaller motor salavaged from a hexbug i paid $6 for. Anyways this has not detered me at all. Back to the drawing board. Oh by the way, its always a good idea to use a breadboard first , no matter how confident you are that you've got it all correct.


 For the brain I bought the following from Solarobitics (i doubled the qty of each item required from teh tutorial) :-

  • 2N3906
  • 2N3904 (corrected thanks Krumlink)
  • 0.22uf Monolithic Capacitor x2 
  • Pager Motor Style 2
  • 1381 J Trigger - 2.7 to 2.9V
  • 24x33mm Polycrystalline Solar Cell (rated at 4.5v / 18ma)
  • 100K 20 Turn Trimpot
  • Wide Field of View Infrared Photodiode Detector

I'm pretty convince I messed up the order or at least mis read the instructions. Thats the only explaination why two separate builds still nothing. I'm saving up some more money to get myself a Breadboard. Will be debugging both photovorescomponent by component. My solar cell and pager motors were setup to be detachable and i didn't include them in my pics. When I get home later I'l show the full assembly. Oh yeah I cheated a bit and used a prototyping boad i bougth at TheSource. See more pictures below :





May 31, 2009

After rechecking and taking apart my second of the two photovores I got two brilliant days of awesome sunlight and to my amazement my photovore sprang to life. It turns out that even though i figured the lights at home should be sufficient to power the solar cell it wasn't at least not for my photovores. The same cell powered my single motor symet but not the photovore. Thanks again to all the commenters. I'm off again to plan my next project.

P.S. Will be posting a video of my final bug shortly

 The final product



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... when you get another day of sunshine.

Do you have plans for that? 

Going to church doesn't make you a Christian any more than going to the garage makes you a car --Laurence J. Peter 


He linked to the plans in his description. The first sentence if I`m not mistaken.
good point... very good point...

thats one heck of a capacitor... and your robot goes in bursts... try subbing in a resistor

also, the solar cell should work only when  the bot senses that there is enough light to power it. let it run off of batteries the rest of the time


some good ideas from

--Benbo Robotics Corp.--

solar beam bots go in bursts - they slowly charge up the capacitor from the solar panel, and monitor the charge level. When the charge level exceeds some value, the capacitor drains into the motor. In direct sunlight this process can be pretty smooth and contiguous, but it otherwise moves in bursts. Removing the capacitor would make the circuit completely nonfunctional -unless a charged battery were hooked up instead, but that would defeat the purpose!

Neat Design - Brill idea for the electronic containment system

Glad you had the patience to wait for "SunLight" to power it.

full score for the photovore

it would be nice if you post schematics

Folks thanks again for all the comments. I desoldered the second build and used teh components to make a SYMET. Within 1hr and 30min I had a fully functioning SYMET. Solar engine twitching and all. I have now narrowed my problems with teh first bot to somewhere between the trimpot and the photdiodes. Will update as soon as I figure out which one was it.


2n3004 or 2n3904?

Not sure if that's just a typo. Or even if it would matter.