The issue at this point is finding a float switch configuration to fit=20 the existing tank, hole, etc. I have been thinking of replacing the=20 plastic fuel tank with a fabricated steel tank. If I ever get to that=20 project, I can study the possibility of hall effect switches. The=20 replacement switches were delivered today. Here's a link to the switches: http://ecatalog.gemssensors.com/ecatalog/singlepoint-level/en/165570 On 10/16/13 6:11 PM, RussellMc wrote: > On 17 October 2013 09:26, Carl Denk wrote: > >> Have to agree on hall effect, but I don't think it's practical at this >> point. > > A Hall sensor could definitely be made to work. > Hall sensors with digital outputs and on/off response are common. 12 VDC > supply is acceptable in some cases. > > You can wire a 3 wire (Gnd, Vdd, Out) Hall sensor in a two wire mode so > that it is supplied with power via a resistor and 2 wire lead and draws > substantially more current when activated so that the drop across the > resistor increases substantially. > > Low current Hall sensors are available that only draw 10's of uA but can > switch 10's of mA so that the swing in Vdd when resistor fed can be a lar= ge > proportion of rail to rail. > > Russell --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .