Hopefully this is the right spot to put this, I’m not affiliated with the company in any way, I just saw that the default spot to buy this seemed to be Amazon, and for anyone who wants an alternative (in Canada), you can get the box for $34.95 right now: IoT Power Relay - Version 2
I’d never heard of PiShop before, but I ordered a couple of days ago, and it just arrived. Wired up and tested, works great. Thanks to the Sienci team for making it such a simple add-on, I never have to reach for a vac or router switch ever again!
Also, it recommends 16 AWG, but I only had 20 AWG on hand, seems to be OK so far, though I can always rewire it if it starts misbehaving.
Alternatives for the big A are always welcome, but the last sentence is a ‘dangerous’ statement. Just do some little math and sum up the max. amps of vac and router, and check if 20AWG is sufficient. If not, the ‘misbehaving’ will be overheating of the cable with possibly dangerous and/or expensive consequences.
Do you have a formula? I can’t seem to find one.
The vac is 5, the router is 6, seems to add up to a total potential draw of 11 amps.
I found a reference that says 20 AWG is fine for 11 amps for ‘Chassis wiring’, but the column next to it says 1.5 amps max for ‘Power Transmission’.
For 16 AWG it says 22 amps for ‘Chassis Wiring’ and 3.7 amps for ‘Power Transmission’ http://calbugs.com/Wire%20Gauge%20and%20Current%20Limits.pdf
Perhaps I’m misunderstanding how the relay works, my thought was that it just supplies a small control voltage to the signal, allowing the power to the router and vac to either flow or be cutoff. Does the current drawn for the router and vac actually travel down the signal wire?
Oh I didnt get you are speaking of the signal wire, then everything is fine - ignore my last post.
You are right, the signal wire is just a signal wire, carrying nearly no amps. Think they recommend 16AWG to reduce possible voltagedrop in case of a really long chosen signal cable… but this shouldn’t be the case in the LM setup.
No problem, it’s probably not a bad idea to reinforce that you shouldn’t run too much current down a wire that is too thin to handle it, particularly if it’s going to be installed/concealed somewhere!
This all got me curious as to what the signal is, so I took out my meter, and it looks like it’s ~4.5v, 70mA, for anyone else who wants to know. It seems to be continuous from the time you input the M8 command, until you send the M9.
I got a little pulse occasionally, but that might just have been the way I was holding the probes.
