Relay for PCB relay node

[RJ_Make]

@johnr Relay specs look good, and fairly small foot print. Not sure on the quality though..

How are you going to handle the step down?

[daulagari]

Do you suggest to use an optocoupler for safety?

I do not see why you would want to use and optocoupler unless some part of the circuit can be touched but like @ServiceXp asks, more crucial is how you are going to convert from 230V to 5V.

[johnr]

Hi thanks for the feedback.

For 230v -> 5v I am going to test the Mean Well irm-05-5.

It is definitely not the cheapest you can find, but I was able to get an ok price for them. It is capsuled which I think is nice, and like I stated above I would like to use quality components for the high voltage parts.

[RJ_Make]

@johnr It's an "OK" transformer, but it doesn't appear to have any thermal protection and it's fairly big.

[daulagari]

Looking at the datasheet of the IRM-05-5 the Derating Curve shows that for 70 degrees the load drops to 0% so it looks like it has thermal protection.

[RJ_Make]

@daulagari Does that classify it as having over temp protection? Seems like every transformer datasheet I've seen has that drop off curve?

In this case I just did a quick look through for OTP, OVP, SCP features. and didn't see any OTP, plus the thing is fairly big.. :-)

[viking]

@johnr great idea! i have spent a few days considering this myself. Have you put any thought in to how it will be integrated to the socket? My concern is that I'd like to re-use the existing mechanical buttons in the house, connecting the arduino as a multi-way connection (swedish: trapp-koppling) to be able to use both mechanical buttons and non-mechanical. For existing multi-way connections I was thinking of adding the arduino as a "cross" (Swedish: korskoppling) in between to facilitate that but that would require two relays

[bluman]

@viking said:

@johnr great idea! i have spent a few days considering this myself. Have you put any thought in to how it will be integrated to the socket? My concern is that I'd like to re-use the existing mechanical buttons in the house, connecting the arduino as a multi-way connection (swedish: trapp-koppling) to be able to use both mechanical buttons and non-mechanical. For existing multi-way connections I was thinking of adding the arduino as a "cross" (Swedish: korskoppling) in between to facilitate that but that would require two relays

I'm working on a Distributed Arduino Node (DAN) that is designed as a "per-room" style controller using the MySensors network talking back to my Vera via serial gateway.
Lighting and temp/humidity is currently working.
I also plan to add Lux and infrared send/receive.

Local control of the lighting is possible using a normal wall switch which is also wired to a relay in a "two-way" switch configuration. Like this:
http://www.electronics-project-design.com/images/TwoWayLightSwitch.GIF

This circuit switches power to a 12V power supply feeding into an LED dimmer/driver like this:
http://www.aliexpress.com/item/Free-Shipping-Constant-Voltage-DMX512-0-10V-Dimming-driver-1-Channel-Single-output-DC12-24V-10A/1329369736.html
This dimmer has a 0-10V DC input which controls the brightness of the LED lighting.
http://en.wikipedia.org/wiki/0-10_V_lighting_control

A rotary encoder is then mounted with the normal wall switch as a dimmer control.
The encoder controls the Arduino's digital-to-analog converter outputting 0-5V. This output is then fed through an operational amplifier with a gain of 2, scaling the output from 0-10V. This feeds the LED dimmer/driver above and is working well with no flicker!

Feedback is required from the 12v power supply so Vera knows if the load is either on or off as there is no way of knowing this with the two-way switching.

This is designed for bidirectional control, from the local wall switch / rotary encoder or from the Vera for example, scene control.

Both on/off and brightness are fed back to the Vera so the DAN and Vera status is kept in sync.

If people are interested I am happy to post more details, sketch, Eagle schematic etc. This is still a "work in progress" though for our new home which we hope to start building this year.

Regards
Bluman

[gregl]

Hi @bluman - Yes please post more details/sketch eagle files...sounds really well implemented!!!

[hek]

@bluman

Candidate for the project contest perhaps?

[johnr]

@viking

@viking said:

@johnr great idea! i have spent a few days considering this myself. Have you put any thought in to how it will be integrated to the socket? My concern is that I'd like to re-use the existing mechanical buttons in the house, connecting the arduino as a multi-way connection (swedish: trapp-koppling) to be able to use both mechanical buttons and non-mechanical. For existing multi-way connections I was thinking of adding the arduino as a "cross" (Swedish: korskoppling) in between to facilitate that but that would require two relays

Would it not be easier to connect the wall switch to a digital in on the arduino? It is the way the fibaro/qubino/ etc wall switches work. Double relays seems like overshooting when you can Control each relay by remote signal.

Actually I was thinking to create a plugin adapter and use something similar to this http://www.ebay.com/itm/MAD-140-ABS-Plastic-Box-Adapter-Enclosure-Case-Hobby-Electronic-Project-/161113131266?pt=LH_DefaultDomain_0&hash=item2583174902
It could accomodate both socket outlet, tempsensor, and proximity sensor, hopefully.

If you would like to but your sensor behind a wall socket, I Think you will need a much smaller Power supply. CHeck this thread:
http://forum.mysensors.org/topic/687/230v-power-supply-to-arduino/2
Especially this Power supply is mentioned which looks nice:
http://fr.rs-online.com/web/p/alimentations-a-decoupage-integrables/7719379/
But I do fell that It have enough Electronics skill to integrate it safely right now.

[bluman]

@hek said:

@bluman

Candidate for the project contest perhaps?

If all my parts turn up from China in time then it should be ready to submit for judging!