emonTH v2.0.2 Terminal Block Assignment Question

A simple question I am sure…

OK, So I purchased 4 of the v2.0.2 emonTH units. On the back of the unit, it labeled pin 5 (on the terminal block) as DS1820B Data D19 A5. Yet on the docs here it is showing the DS1820B data as A3 (D17). On the schematic it is also shown as ADC3/Digi17.

My question is if I want to hook up a sensor to screw 5 on the terminal block, how do I address it in my code? A5, A3…?


I don’t have an emonTH V2 to check for you, but I would believe the circuit diagram. On the V1, the data wire was ADC5/D19, so I imagine this has been carried over from that.

The standard sketch refers to pin 17 as “ONE_WIRE_BUS”, which agrees with the schematic.

One for @glyn.hudson to check and correct, methinks.

Working from memory (I’ll try confirming this later) the new v2 uses a I²C temp and humidity sensor so A4 and A5 (aka D18 and D19) will be tied up as they’re the hardware I²C pins. So the 1wire assigned pin must be different on the v2 to the v1.

It looks like it’s the pcb printing that is wrong, possibly not updated from the v1?? The (current?) board image does show the 5th pin as “A5” (ringed in red below)

the schematic isn’t complete, it should have a “ADC3” label here

and also some “SDA” and “SCL” lines and labels here

to marry up with the labels here

so it looks like your good to use pin 17 as indicated by Robert and ignore the terminal label.

[edit - issues raised on github]

1 Like

@pb66, @Robert.Wall

Guys - Thanks! I was scratching my head trying to figure it out! A3 it is.