If you want to, and have additional I/O's available, the pic could put these resistors in between the pot and ground for you (one I/O per resistor required). I apologies in advance for not understanding your difficulty with the A/D application. What is your Vref and A/D accuracy? Have you plotted your response? Could some fuzzy logic help you automate your code to derive the position? This may be insignificant, but if required, with a cap and an op-amp circuit, you could create a 9 bit D/A from the pic if your code can refresh it often enough. {slewrate} ----- Original Message ----- From: "Brooke Clarke" To: Sent: Monday, November 18, 2002 11:20 PM Subject: [EE] Circuit for Pot & Switches > Hello: > > The Piher N15 trim pot has no mechanical stop and the lowest value is 5 K ohms. > I have come up with a simple circuit that puts a small resistor between the pot > and ground then with a 4K7 resistor in series with the wiper going to the A/D > input pin you can put a NO Push Button switch from the PIC pin to ground and > have a pot and switch on one PIC pin. I think you should be able to have 2 or 3 > NO PB switches and the pot on a single PIC pin, but so far have not come up with > a circuit to do that. Maybe it needs a transistor or op amp to work and have > less than 10 K Ohms source resistance for the PIC A/D input? > < http://www.piher-nacesa.com/pdf/n15USA.pdf > > Does anyone have a circuit for using 2 or 3 switches and a 5 K Ohm pot on a > single A/D PIC pin? > Note that you should be able to use this pot in a fashion similar to a 10 Turn > pot, except there is no restriction on the number of turns. Also I think there > is a way to connect two pots together to make a 360 degree position sensor. > Thanks, > Brooke Clarke, N6GCE > http://www.prc68.com -- 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