MarkoeZ 68 Posted August 16, 2011 Share Posted August 16, 2011 Hiya, quick question since my general electronics skills were almost non existent before this project. For my car project i'm using the 6x AA battery unit from the original car for the drive power. Can i use the ground from that, and attach a wire after the 2nd AA battery to tap off about 3 volts for the board containing the MSP? Or will that not work. My guess is no, but if possible it would save me either an extra battery pack inside, or voltage regulator circuitry. Thanks, and Cheers! MarkoeZ Quote Link to post Share on other sites
RobG 1,892 Posted August 16, 2011 Share Posted August 16, 2011 Sure it will work. You can tap 2nd battery's + for 3V, then you can use 9V to power the motor. MarkoeZ 1 Quote Link to post Share on other sites
nuetron 64 Posted August 16, 2011 Share Posted August 16, 2011 Can i use the ground from that, and attach a wire after the 2nd AA battery to tap off about 3 volts for the board containing the MSP? That depends on several things: What kind of inputs (if any) to your micro will you be using? +3v? +9v? (not a good idea) What kind of inputs will your micro's outputs be interfaced with? +3v pull-up, +9v pull-up (again, not a good idea), high impedance? MarkoeZ 1 Quote Link to post Share on other sites
zeke 693 Posted August 16, 2011 Share Posted August 16, 2011 As long as everyone has the same point of reference - Ground. MarkoeZ and nuetron 2 Quote Link to post Share on other sites
MarkoeZ 68 Posted August 17, 2011 Author Share Posted August 17, 2011 Thanks for the replies guys! And yeah, i don't know much yet, but i do know better than to start attaching 9 volts to a 3 volt microcontroller Cheers! Quote Link to post Share on other sites
nuetron 64 Posted August 17, 2011 Share Posted August 17, 2011 Sorry, was just making sure... Quote Link to post Share on other sites
RobG 1,892 Posted August 17, 2011 Share Posted August 17, 2011 jsolarski and MarkoeZ 2 Quote Link to post Share on other sites
MarkoeZ 68 Posted August 17, 2011 Author Share Posted August 17, 2011 Sorry, was just making sure... Oh sorry, nothing negative intended. Thanks And yup, that diagram shows how I was planning the setup. Cheers! nuetron 1 Quote Link to post Share on other sites
cde 334 Posted August 17, 2011 Share Posted August 17, 2011 [attachment=0]batt.png[/attachment] D: Best way to fry the 430. With any motor, you need a protection diode. And most likely, a darlington pair transistor. Quote Link to post Share on other sites
RobG 1,892 Posted August 17, 2011 Share Posted August 17, 2011 This is simplified schematic, for illustrative purposes only. I should've used rectangular load symbol (updated schematic with diode.) Quote Link to post Share on other sites
cde 334 Posted August 18, 2011 Share Posted August 18, 2011 This is simplified schematic, for illustrative purposes only. I should've used rectangular load symbol (updated schematic with diode.) Safety first, right? Oh, and to O.P., you should keep in mind that hooking it up that way can lead to uneven wear on the batteries. Probably negligible considering the msp's low current usage, and the intended platform (High current RC car). Just a heads up. MarkoeZ 1 Quote Link to post Share on other sites
MarkoeZ 68 Posted August 18, 2011 Author Share Posted August 18, 2011 This is simplified schematic, for illustrative purposes only. I should've used rectangular load symbol (updated schematic with diode.) Safety first, right? Oh, and to O.P., you should keep in mind that hooking it up that way can lead to uneven wear on the batteries. Probably negligible considering the msp's low current usage, and the intended platform (High current RC car). Just a heads up. Thanks for the heads up, but yeah, the 3 volts is only powering the msp430, a shiftregister and a couple of leds. So should not make a noticable difference i think. And most of the time it will be powered by usb anyway. I was just looking for a quick fix to do standalone tests. With the motherboard, 2 added module boards and the original car drive board (using the h-bridges from that, and it has protection circuitry as well) the inside of the car is getting a bit cramped . Cheers! Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.