I think I might understand a bit of what you said. I should have explained myself, but I was not planning to use pots for the 12vdc motors, that question is for another small tank I'm building first. Anyway, I am basically trying to find the cheapest way to make the 12vdc drill motors run with reverseable, variable speed with a transmitter. If the PWM is what I need, could you explain or send me a source on how to build this controller?
Cheers, —Mike Måne Message sent by way of mobile device On Aug 16, 2009, at 8:16 PM, Don Shankin <[email protected]> wrote: > Mike, > > If you'd like to go down this road I can definitely help you out > along the way. Just as an example, I think for control of my Abrams > it would be cool to use a Wii Nunchuck/microcontroller with an Xbee > pro, so we'll see how that goes. > > Yeah, I know how to hook up a pot, but like I said, I would suggest > using pwm instead. A potentiometer is a resistive voltage divider, > and wasted energy in these devices is directly proportional to the > current used (which will be high running tanks!). Using PWM gets > rid of this problem, because it basically turns the voltage on and > off very quickly. The inductive load of the motor (the motor > windings) averages out these on and off transitions. (for example, > if we switch between 0 and 5volts with 5 volts "on" 50% of the time, > the motor thinks that it's getting the average, or 2.5 volts). > There are other advantages as well, but for high current motor > controlling this is the way to go > > On Sun, Aug 16, 2009 at 4:31 PM, Mike Måne <[email protected]> wr > ote: > > George: I was considering that idea, but using servos to control these > 15-year-old things probably won't go very smoothly, or as you said, it > would be delayed. Also, a switch must be thrown to simply reverse the > motors. I think it would be best to simply replace the original > controls with a receiver. > > Don: The term "microcontroller" sounds like it must be a cool idea. > I'm not an electrician, so you might have to send me a little > instruction for guidance, but your help would be appreciated. Do you > know how to hook up a potentiometer? > > Thanks again, > > -Mike M. > > On 16/08/2009, Don Shankin <[email protected]> wrote: > > I would suggest a PWM controller to control the speed. I'm not > sure how > > much they are to purchase, but if you're handy with electronics/ > programming, > > you can make one on a microcontroller. I made one on an Atmel > > microcontroller that sets the PWM duty cycle based on serial > commands. If > > you're interested I can send you the source for this. The only > parts you > > need are an atmel micro, a max232 level shifter, and a few > caps... less > > than $10 in parts > > > > > > > > > > -- > -Mike Måne @ > http://moonrcprojects.googlepages.com > > > > > > -- > ---------- > Donald Shankin > Computer Engineering Undergrad > Blue Marble Security Member > IEEE Vice Chair, MTU Chapter > NSBE Telecommunications Chair, MTU Chapter > CAEL Partner > (507) 301-2499 > [email protected] > [email protected] > ---------- > > > --~--~---------~--~----~------------~-------~--~----~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] Visit the group at http://groups.google.com/group/rctankcombat -~----------~----~----~----~------~----~------~--~---
