Hello, I'd always found that the Motorola (apparently now marketed as Freescale Semiconductor) sensor fit that bill quite well.. Check out the MPXV5050 ($13.64 each from Newark).. http://www.newark.com/jsp/search/productdetail.jsp?SKU=3D75C3918&&CMP=3DAFC= -SF-T11 Many ranges and options to choose from. Best regards, Mike On Wed, Jun 13, 2012 at 4:57 AM, KPL wrote: > Hi, > > I'm constantly having trouble with pressure switch of a water pump, > which is supplying water from a well for a house and garden. Setup is > far from optimal, and seems like normal, membrane-activated switches > are having trouble with this. I am sure there are better switches > available somewhere, but I had an idea to build one by myself, using a > PIC. That way I could have better control of ON and OFF pressures, and > hysteresis, probably also some kind of dynamic self-adjusting, to cope > with completely different situations of supplying just home, vs > supplying water for garden. Soft start of a pump motor could be > implemented easily too. > > Any ideas what cheap pressure sensor could be used? Sensor has a > direct contact with water. > Some kind of a digital output would be best, but i can live with > analog signal too. > Best if that sensor is widely available, that is, used in some > consumer equipment. > > Somebody recommended to use oil pressure sensor from a car, that has > continuous-signal sensor, not just a pressure switch, but I do not > have an exact car model that uses this kind of sensor. > Probably sensor, designed to contact with oil, would not live very > long with water, but it's ok to replace it sometimes if it's cheap > enough. > > I'm interested in pressures between 1 and 6 bar, or so. > > -- > KPL > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 Life is Good! --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .