Hi Seb, finally took the time to have a look at the schematics... And, finally yahoo allows me to send mails to the list again a bit more regularly... ;-)
>>Something in between. I'm using 1% accurary >>resistors: http://sirbot.org/sirbot-modules/dc-motor-controller-board/dcmc_rctank_schematic.png To be honest, the resistors shouldn't do anything bad. I think you don't really want to _measure_ the voltage, but compare it to some previous values. So the resistor tolerances, together with the motor characteristics, are stored in your reference values. >> Is there a dedicated 5V reference, or do you simply use one supply to power >>different devices? Then your reference voltage could introduce errors of >>several percents. >Vref is the one used by the PIC itself. So yes, it may be shared with other >devices (but not the motors') The board has its own linear regulator, that's not bad for a start :-) Switching power supplies are good for computers, but not as reference voltage for measurements. But, if it's a 7805 or the like, remember that it outputs _about_ 5V. Each 7805 has its own voltage... And it changes over temperature. It's good for power, but not for reference. A cheap way would be something like LP2950CZ, a higher-precision voltage regulator that has a quite good accuracy when loaded very little, or a true voltage reference like from the LT1021 series, but those do cost money. Just for theory... I don't think you'll need anything of this to find out if your motor is stuck :-D Greets, Kiste -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
