Snap crackle and pop <- capacitors on the Motor board :(

batteries can supply a lot of current. If you have a spare power pack, use that to get your wiring going and once the motors are working then you can put the battery. This way, is something goes wrong, the voltage should drop since you power pack will be about 500ma

Thanks Gus.

I had my little guy working on my lower voltage battery. My issue was that my battery pack was to big and bulky at 7.2v. This battery would give more juice and for a longer period of time (1200 mAh vs 2200 mAh).

When I used this battery - and likely swapped the polarity - I fried my chip.

So before I connected this battery to the board, I was hoping that someone would look at my photos and say - yeah you’ve got it wired up right.

As mentioned before - I’m developer and don’t have any electrical background. Using the JST connectors has made life so easy for me. Otherwise I doubt I would have spent money on FEZ or any other microprocessor board - NETMF or otherwise.

Thanks again

It is still not clear in images on which wire is positive.

do not connect any wires to FEZ or motors yet, then only worry about the 2 wires from your battery where plus goes to plus and minus goes to minus. If you are still worried, try connecting the wires for couple seconds then disconnect them and feel if the board is getting hot anywhere. No caps or chip should be hot nor even warm.

Thanks for the help Gus!

I’ve got the white wire connected to the + input on the motor board. My black wire is connected to the - input.

I was planning on connecting battery black to motor board black (-).
Then I was going to connect battery red to motor board white (+).

Are there times when that black is used for + in a battery?

(once I get some semblance of a working bot, I’m showing it off to my friends and telling them how FEZy it is!)

I have never seen black used for + but maybe you are not lucky! :frowning:

One of your pictures show the voltage 12.2 on a mulitmeter with Black - negative and Red - positive… That is correct for most batteries (some batteries have a white wire, but thats for the NTC temp sensor )

Can this board take 12 volts ? I’m sure you mentioned a 7.2v battery

Be careful of one thing… If a battery goes dead and someone connects it up wrong you can charge it backwards ie… -12v

Cheers Ian

Thanks IanR for the response.

The board can handle 30v and the motors up to 12v. This battery also has a separate 4 pin connector which that provides options of ~4v, ~8v and ~12v. I may wind up using the 8v option for both my board and FEZ.

I think I blew out my first board because I did that - reversed the polarity. At that time I had 2 black wires on the board - one solid, and the other with a faint white dashed line. It’s very likely that I didn’t take head to the markings on the wire.

Thus I’m being overly cautious this time around. As soon as I get the layout and wiring finalized, I will be adding power connectors so that polarity can’t (or make it very difficult to do so) be reversed.

I found a cracking site once… I’m dammed if I can find it again…

This Russian genius had a small circuit built with mosfets arranged so you couldn’t power it wrong it only had a .6v drop on the supply… Most of these designs take 1.2v of the supply.

I want to include it in all my designs ( no more smoke )

Cheers Ian

Makes perfect sense to me as well - more of a protection against myself than anything :wink:

If you come across it, please let me know.