How to create a smart 3-way positional switch?

Question

Looking at this switch as an example: https://www.directindustry.com/prod/tacthill-kynoppe/product-192123-1963276.html

I have a similar 3-position switch in my garage that controls a water pump. Central position = off, down = permanently on, up = timer.

My goal is to replace this switch with a smart switch that I can incorporate into my home automation. Ideally I'd love a z-wave compatible one, but I'll just be happy with any if it stops me having to visit this switch regularly.

Does anyone know if there are such a smart switch, if not, maybe I could build one even with an arduino if need be, but it'd be nice to not have to buy all those parts, particularly the z-wave transmitter.

Any guidance at all on how I could achieve this goal would be great.

Thanks

you provided no information about what you are controlling with the switch, so the only suggestion is to use two relays to replace the switch .... choose relay contact rating to be the same as the switch contact rating .... control the relays with a microcontroller — jsotola, Jul 10 '20 at 16:15
Re-reading your post I realized you'd prefer not to use a hub, so I added another option to my answer. Good luck! — P2000, Jul 11 '20 at 15:53
@jsotola I mentioned that it controls a water pump and I explained the 3 positions — Dave Goodchild, Jul 11 '20 at 17:58
you said nothing about the voltage and electric current levels at the switch ... basically, the switch is controlling an unknown device — jsotola, Jul 11 '20 at 18:07

P2000 · Answer 1 · 2020-07-11T15:52:25.747

A 3-position switch would be implemented in z-wave by independent 2 on/off switches, and the "3-position" function is programmed as a "radio-button" activating one or none (but not both) of the 2 on/off switches.

If it's ok to switch one or the other mode, and no hazard exists if both are on, as in your case (no harm if timer is on and switch is also on), there are two-relay modules that could fit inside the electrical box of your current switch.

Have a look at this:

https://www.homecontrols.com/Qubino-Flush-Relay-QUZMNHBD3

If you do not want to use a smart-hub, then you could try it with a "remote switch". There are models that provide one remote to control several outlets, e.g. for outdoor lighting.

https://www.amazon.com/Etekcity-Weatherproof-Electrical-Unlimited-Connections/dp/B078YL37MM?ref_=fsclp_pl_dp_12

If you are somewhat handy (and I think you are, if you are thinking about the Arduino), you can wire the double-relay unit so that it overrides or replaces your wall switch.

Since you are using an independent timer as one connection option, I don't think you can use these remote receivers straight out of the box. You have to open up the case and modify the wiring at the switching poles of the relay. Basically you reverse wire the switch: the relays have to select between two input plugs (one powered permanently, one powered through the timer), and supply one socket.

Simply reversing the input plug and output socket of the entire unit would not work because the unit derives its own power from the plug side.

I can update this answer with a sketch if you need one.

score 0 · Answer 2 · answered Jul 10 '20 at 17:55

schematic

^{simulate this circuit – Schematic created using CircuitLab}

The OR arrangement requires you choose XOR or exclusive OR in the remote operation as one over-rides the other when active.

The AND series arrangement gives you exclusive OR using a SPDT.

There are over 3000 interoperable Z-Wave products throughout the world.

But perhaps you can find a Up/Stop/Dn Blind Z wave Remote that has the single pole or double pole function your prefer to drive your AC power Relays using either DC coil power (more efficient) oR AC coil power.

score 0 · Answer 3 · answered Jul 11 '20 at 06:10

Here's how, using 2 DPDT relays K1 & K2 (could be a 2 channel RF relay board).

The above network would replace the toggle switch.The bottom terminal would get connected to the point where the centre terminal of the toggle switch was and the other two where the end terminals were.

The logic would be 'K1 on' or 'K2 on' or 'both off'.

How to create a smart 3-way positional switch?

3 Answers3