Power Supply for Mindstorms RCX 2.0

One thing that really annoys me when I’m programming the elsewise great Lego Mindstorms® Set, is the need to upload the firmware and all programs again, when one has to exchange the batteries. This has been fixed for the brand-new NXT System, but how to deal with that for the oder RCX? Yep. Connecting a Power Supply is easy:

I screwed up the case and found that it’s quite easy to attach two cables. Just make sure, the power is about 7.5 V. Use a stabilized Power Supply with not much more than 500 or 800 mA. Use a Multimeter to check the actual voltage ’cause many supplies deliver much more current than actually printed on the labels!

Of course you should do this only on your own risk. The guarantee will expire if you open the brick. Don’t blame me. Stick to batteries if you have never done things like these before!

Warning: do not use batteries and the power supply together. There’s nothing to say against some seconds overlap (inserting batteries, then removing the PS-Cable at once – or vice versa -), but if you feed voltage/current into normal batteries it is very likely that they will explode or overload!

Possible upgrades:
– using a charger circuit, so that the batteries could be loaded and remain inside the brick
– using a different cable breakout position than I did. My solution is not so good when you want to build the brick into something else… haven’t thought enough about this :-