@MasterCATZ said in help needed with multiple temp sensor data logging project: @wallyllama thanks that is what I feared, and would have made the job a lot easier how ever I was thinking about doing it the other way to keep the other probes already made backward compatible as they used pins 1-4 just trying to weigh up the pro's and cons also out of all those 3 way splitters only 15x actually have all pins functional ... The big "con" is the risk that someone will come along and try to use it in a standard way. so trying to think of a way to still use the dodgy ones by having redundancy's in place I think the way the PSU is wired up at the moment is the correct way things don't seem to be stressed out this time I am also raising my polling times as I think I read somewhere it takes the sensors 750ms to perform a function and uses 1.5 mA each? Sensor Poll Period: 1000 to 30000 Switch Poll Period: 100 to 1000 my way of thinking this should still have all 60 sensors read in 1 min? 60 sec / 1000ms for Switch Poll period? There is a function that tells all the sensors to start a temperature conversion, you could then read each one individually. So it would be 750ms + (60 * pollingtime) to get them all. I dont know if you trade speed for reliability or not. You may be able to interleave conversion requests and polling. Convreq1 poll30 convreq2 poll31 8convreq3 poll 32 .... convreq 60 poll29 - loop Maybe overkill if 1 reading per minute is enough