DS1820 Mounting
Home Page E-mail Doug

DS1820 Mounting Ideas
My HomeVison Pro controller can read Maxim/Dallas Seminconductor DS1820 digital temperature sensors. Up to 64 of these can be strung on the same pair of wires.

I needed a way to mount these sensors in an unobtrusive way and still be able to easly wire them along a single cable. What I decided was to crimp them into RJ-45 plugs. The sensor is totally recessed within the jack for protection.

The hardest part was choosing a wiring scheme. For ease of daisy chaining multiple sensors on a single cable, I decided to take two pairs from the cable and punch them across both positions of the RJ-45 jack. This allows the cable to not be cut. The Levition jacks I used came with a plastic punch tool that does not cut the wire.

I will probably change my wiring scheme a little to make it even easier. I currently skip one pin when inserting the temperature sensor. This is to keep the data line on a different pair than the other wires. One of the DS1820 application notes says this helps reduce cable capacitance between wires. It might be easier to change the order of the wires and crimp the sensor on three contiguous pins.

More details will follow when I have time.

Here are a few pictures:

RJ-45 plug
cable entrance view

RJ-45 plug
pin side view

RJ-45 plug
side view

RJ-45 plug
tab side view

RJ-45 jack wired with temperature plug inserted. This assembly was later mounted in a wall plate.