Picture of Solar-Powered Robot

A while back I made dozens of robots which were in large part inspired by BEAM Robotics. For those unfamiliar, BEAM is basically a special method of robot building with an emphasis on biology, electronics, aesthetics, and mechanics (hence the acronym BEAM). One thing that sets BEAM apart from other approaches to robotics is its insistence on using radiant energy (predominantly solar power) and its tendency towards reuse and minimalism. While I heavily borrowed from the BEAM ethos and aesthetics, the robots that I built were not quite the same (they were all battery powered for starters).

Since BEAM robotics was such a large source of inspiration, I always wanted to try my hand at building a solar robot. However, rather than simply building another BEAM robot, I decided to incorporate solar into my own style of robot building. Instead of having it be powered entirely off the sun, I decided to incorporate rechargeable batteries. This means that at any given time the motors can be running off either the batteries or solar panel, depending on which can provide the most power. The solar panel is also recharging the batteries when the sun hits it. This allows the bot to run off of the sun, but not be entirely reliant upon it to move.

I think my approach merges the two styles nicely, and is a fun and simple experiment in robot building.
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Step 1: Materials

Picture of Materials
You will need:

(x1) Solar panel (Radioshack #277-052)
(x2) Standard servos (Radioshack #273-766)
(x3) 1N5817 schottky diodes - NTE578 equivalent (Radioshack #55052253)
(x1) 9V battery snap (Radioshack #270-324)
(x8) AA rechargeable batteries (Radioshack #23-760)
(x1) 8 x AA Battery holder (Radioshack #270-387)
(x12) Wire-tie mounts (Radioshack #278-441)
(x1) Ruler (12" - 18")
(x2) Wall mount adhesive hooks
(x1) Misc. zip ties
(x1) Shrink tube
robobot31125 months ago


Jacky P8 months ago
You could add a photocell and make it only turn on when it has light as well.
Jacky P8 months ago
I got a more powerful solar panel for about $9 online (us)
Fikjast Scott9 months ago

I like the use of the ruler for the structure.

great job

I do not have very much access to sunlight at all. Would this lamp

work as an alternative? If not, what would you suggest?

DieCastoms10 months ago

Ok, I'm confused (yes I admit it). From my understandings of diodes, you are wasting two of them ...


SP 2====> | <====3 Batt.

Ok, I understand that 2 prevents battery power from feeding back into the solar panels, and that 1 allows solar power into the battery pack. Don't one and 3 completely cancel each other out? 3 prevents solar power from reaching the batteries, yet 1 allows it, but 1 allows power to go in the direction that 3 prevents??

If the only thing you are protecting is battery power into the solar panels, than diode 2 is the only one accomplishing anything.


randofo (author)  DieCastoms10 months ago

Check out the explanation halfway down this page:

uncle frogy10 months ago

I have been studying this project and come to the conclusion I do not know enough about servos. I am also confuse by the diode circuit. The link to the Shack catalog listing gives me an other question. Why that motor and not the continuous bidirectional motor for the same price? It would require no modification. Was it a size or current problem?

looks like a small switch could be installed between the motors and the power.


ynze10 months ago

Great little beambot! The solar panel seems expensive though (US$ 20). Is a 1.5 Watt panel really needed?

jaff52110 months ago
great idea. 3 doides is a good way, but does it really work?
lonesoulsurfer10 months ago
Great little BEAM robot. Really love the use of the 3 diodes - never thought of using them that way!