Suggest you have a look at the Open Source Motor Controller groups efforts - Yahoo Groups -> osmc. This group has also developed an RC interface, a couple of 'brains', etc., and are working on (I think) a current limiting add-on and various other additions. Strong bias towards battery powered, high amp battlebot stuff. Actually the controllers they've developed are dual channel, so would seem that your wheel has already been developed to specs. Think a couple of other related 'open source' groups may have also been created. Is apparently a 'Vantec' killer - if that means anything to you. Pete S. P.S. A search on "Open Source Motor Controller" finds the initial web page created to get the group started. This page is very out-of-date - everything (inc. documentation, schematics, ongoing discussion, etc.) has tranferred to Yahoo Groups. At 11:40 AM 8/02/02 -0500, you wrote: >David Harris wrote... > >"What kind of current do you want?" > >Answer... >I'm thinking in the 100-150 Amp range. Basic outline is for a PIC that >senses 2 standard R/C servo channel pulses on 2 inputs and converts this to >signals for 2 H Bridge drives, 1 per motor. > >Questions that I have at the moment are... >1. Whether to poll the inputs or trigger the pulse width count using an >interrupt? >2. Whether to drive 4 PWM outputs or just 2 with a 3rd direction control >(per motor)? The latter has the advantage that it is less likely to get >into a drive for all 4 FETs in the bridge. >3. How to handle the current in the output stages? MOSFETs like the BUZ11 >can take 30A, 50 Volts, and have an on resistance of 0.03 Ohms and there are >many more out there that can handle 80V and 50A. I'm thinking of >paralleling up 2 or 3 MOSFETs per channel with the resistance of a carefully >designed PCB providing some kind of current sharing resistor capability. It >seems like a no brainer to use opto-isolators to separate the PIC output >from the MOSFET gate drivers. > >Enough detail? > >Ted PICman@Portfoliopm.com >www.portfoliopm.com > >----- Original Message ----- >From: "David P. Harris" >To: >Sent: Friday, February 08, 2002 11:27 AM >Subject: Re: [PIC]: Robot Motor Controller > > > > What kind of current do you want? > > David > > > > Ted Mawson wrote: > > > > > Hi Bob, > > > > > > Your description is exactly what I was thinking of. I'd be very >interested > > > in seeing what you've got so far. > > > > > > Have you got the H bridge FET drive stuff fully worked out? I have some > > > specific ideas in this area, seems to me that it should be possible to >make > > > a very high current H bridge by using MOSFETs that can have on >resistances > > > of 0.03 Ohms! > > > > > > Ted > > > ----- Original Message ----- > > > From: "Bob Blick" > > > To: > > > Sent: Thursday, February 07, 2002 10:16 PM > > > Subject: Re: [PIC]: Robot Motor Controller > > > > > > > I've done something like that for a fighting robot. Takes two R/C > > > > receiver channels and generates pwm for two motors. Treats one > > > > stick as fwd/rev and the other stick as left/right. One motor goes on > > > > each side of the bot. Also monitors the current on the h-bridges and > > > > limits current. Has extensive amounts of code designed to reject > > > > spurious signals coming from the receiver. > > > > > > > > I was planning to do a web page about it. If you can wait, then it > > > > would come with some explanation, but I can send it to you if you > > > > want to figure it out yourself. > > > > > > > > Uses a 16F876, coded in HiTech C. > > > > > > > > Cheers, > > > > > > > > Bob > > > > > > > > On 7 Feb 2002 at 18:10, Ted Mawson wrote: > > > > > > > > > To save me re-inventing the wheel, can anyone point me to a PIC >project > > > that takes 2 Radio Control servo pulse inputs (from an R/C receiver) and > > > generates the PWM drive for 2 DC motors running in H bridge mode via >FETs? > > > > > > > > > > Thanks, > > > > > > > > > > Ted > > > > > > > > > > -- > > > > > http://www.piclist.com hint: The list server can filter out >subtopics > > > > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > > > > > > > > > > > > > -- > > > > http://www.piclist.com hint: The list server can filter out subtopics > > > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > > > > > > > > > -- > > > http://www.piclist.com hint: The PICList is archived three different > > > ways. See http://www.piclist.com/#archives for details. > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > > > > > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu