Connect Two Professional Development Boards Using One Battery Source?

Bill Chennault

All--

I am not satisfied with the big Jameco breadboard on my robot, Ugly Buster. It is very large and that is nice, but it is not as mechanically sound as a PDB. I have two PDBs sitting in drawer. I want to run both off a single 12 volt battery source (two 12 amp hour batteries in parallel for a total of 24 amp hours). IF I can do this, THEN I can eliminate the dual 7.2 volt, 8400 mah battery packs that operate my logic and will be able to run EVERYTHING off the 12 volt batteries.

What I would LIKE to do is build a simple "Y" connector that allowed me to plug 12 vdc into both PDBs. There would be logical connections between the PDBs, breadboard to breadboard. Can I do this or am I missing something? Remember that I am a newbie.

Thanks!

--Bill

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
You are what you write.

Mike Green

You can even buy ready-made Y connectors at RadioShack. The PDB is rated for use with a 12V wall-wart. It should be OK with your batteries, but you'd be better off using a regulator to drop the 12V to 8V (LM7808 regulator). Another good choice would be an LM317 adjustable regulator. RadioShack sells these along with heatsinks and the filter capacitors. You would like as much isolation as possible from the electrical motor noise and this will also take some of the heat off the regulators on the PDBs.

See page 9 of the LM317 datasheet (www.national.com/ds/LM/LM117.pdf) for a good sample circuit. You'd want a 0.1uF input capacitor mounted close to the regulator and at least a 100uF 15V output capacitor.

Bill Chennault

Mike--

As always, thank you for the answer. I would have THOUGHT about the regulator because I have learned that the energy must go SOMEWHERE. However, I doubtless would not have implemented one. You have made it too easy to skip!

Thanks!

--Bill

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
You are what you write.