> One interesting thing. The MOSFETs are rated at around 70A, but the > leads look smaller than a 7805 regulator. I wonder if they could > actually carry that amount of current. > Tony, The lead size on the MOSFET's is dependant on the "resistance", rather than the "diameter. Sounds like a great project you are working on!!!!!!! ----- Original Message ----- From: Tony Nixon To: Sent: Monday, March 06, 2000 9:59 PM Subject: virtual car > Whew!! > > Finally got somewhere with this project. > > I've now got a PIC16F877 talking to another PIC16F877 over a radio link. > > The first PIC monitors steering and throttle positions from the virtual > car, plus some other stuff and relays all the info to the other 877. > > This then tells two 12C672's to move the real thing via some rather > large servos. > > I just blew a 10A fuse trying to do a quick steering direction change, > but I noticed the motor manufacturer specified up to 20A when this > happens, so maybe a 30A fuse is needed. The motor is braked when told to > stop or change direction, so I may have to put in a bigger dead time as > well. It's pretty hairy the first time you apply power to these things > considering the power behind them and not exactly knowing what's going > to happen. You can take all the precautions in the world, but there's > always some little thing you forgot :-) > > Still, it's somewhat gratifying to know the darn thing works thus far. > The MOSFETs didn't even get warm during fairly hard testing. > > I was a little bit worried how the PIC would perform being on the same > PCB as the power drivers, but it seems to handle things ok. It uses a > seperate power supply and controls the power section via opto couplers. > > One interesting thing. The MOSFETs are rated at around 70A, but the > leads look smaller than a 7805 regulator. I wonder if thay could > actually carry that amount of current. > > -- > Best regards > > Tony > > http://www.picnpoke.com > mailto:sales@picnpoke.com >