Let's Make Robots!

Motor controller

So I bought this motorcontroller: http://www.pololu.com/catalog/product/713/resources and I plan to use it with a picaxe 18 M2.

I powered the entire system with a 9V battery, I made all the connections needed, including a led indicator that is connected to the positive terminal of the 9V battery, and I also have put a 5V regulator for the picaxe chip. The problem I have is that when I connect the "vmot" to the 9V positive terminal, the led turns off and when I check the voltage between "vmot" and the ground, my multimeter shows 0 V. 

I'm not sure, but I think this is happening because of the battery, maybe I should have put 4 AA batteries. If not, what did I do wrong?

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it is a problem. I tried with 3 AA batteries and it still does not work. After checking my multimeter, it looks like the "vmot" pin of the motorcontroller is actually a gnd terminal. kinda strange. When I connect it to the + terminal, there are sparks and the 5V regulator gets hot.  

... the little chip is not a voltage regulator it looks like some kind of mosfet. 

I getting hot can only mean it is shorted somehow, have you checked the pins for shorts?

since there are no stupid questions here - i have a somewhat similar question, but my thought is to use a 12VDC LiFePo4 battery pack, 4S1P configuration hooked up to a DC/DC converter, 12vdc to 9vdc...

Would there be a problem with that set up - my reason for asking is for a special project that i have not introduced yet, but i will in a new thread...

... is that they are putting out around 350mA ... their internal cells are very small. 

With that LiPO pack you should be on the safe side.

... very weak for motor applications.

Use AAA or AA to power motors. 9V is only good for powering small loads.