NXT on solar power

Just as I was thinking about what it would take to make a mars rover with the NXT, I found the dSolar panels from Dexter Industries. How cool is that, a mars rover that actually runs on solar cells!

However, $100 seems a bit expensive for such a nice-to-have feature. Looking around on eBay revealed you can get more power for half the money, only it doesn’t come in a LEGO friendly package.

I bought them anyway, and documented the customizations. Soldering iron required!

[update]: It is recommended that you put diodes between the panels, see comments below.

So basically I connected the panels in parallel with a few plugs from an old computer. The whole thing is connects to the NXT via 2 fake batteries made of hot glue cartridges. To prove it really works:

I can’t wait to make a robot with these.

3 thoughts on “NXT on solar power”

  1. Good idea, but I think it is a good idea to put at least one diode in the wiring so that it will not work if you connect it up the wrong way round.

    There is a slight voltage drop across the diode (usually < 1v) so you might need to add another solar panel if the output is low to begin with. better than risking destroying the NXT though.

    A better alternative (but with greater voltage drop), is to use 4 diodes or a ready-made rectifier. This means that it will always work, no matter which way you connect the wires.


    Like the crane btw, very simple but effective.

  2. Hi again. Looked through ebay for solar panels and see that it is recommended that you put a simple rectifying diode (search for 1n4* diode* to get the lowest prices) in the wires from each panel. I think this is to stop a shaded panel from getting power shoved in by other panels in better light.

    Only necessary if you are running the units in parallel.

  3. Thanks. The panels I bought included USB headers and diodes in the package, I guess I should attach them, as your recommend.

    I would hope the NXT is protected against “kids” putting in “the batteries” the wrong way around, but the point about shade is very much valid regardless of NXT protection.

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