Smaller then a conventional Relay board

[Aelita Sophie]

Lets explain the situation first. I've got an airventilation system in my house. Currently there is 1 remote controller that works through RF to control the system. Though I like to make my home smart. I took it apart to see what I was dealing with. Appearently I'm working with a CVE ECO RFT. It's a 2010 model I believe but that doesnt really matter. I've found an article that explains how to reverse engineer the signal and recreate it through an arduino and a RF transmitter on a 868mhz band. That's all fine and dandy, but a bit to overkill for what I want to do. I figure to just desolder the original buttons and hook it up through a relay board with an WiFi enabled arduino. Also taking a buck converter to replace the 3v battery.

I figured I could go the classic Relay or solid state. But for the way I'll be using it, I feel like its a bit overkill. And most important of all, to big. Is there a way to have the same results like a relay, in a smaller package?

 

Link to the article as refference; http://www.progz.nl/blog/index.php/2014/12/reverse-engineering-remote-itho-cve-eco-rft-part-2/

[manikyath]

so.. if i understand correctly, you're wanting to emulate button presses with relays?

 

the smaller way would be to look at how the keypad is wired, and just emulate that instead of all the individual buttons.

[Aelita Sophie]

2 minutes ago, manikyath said:

so.. if i understand correctly, you're wanting to emulate button presses with relays?

 

the smaller way would be to look at how the keypad is wired, and just emulate that instead of all the individual buttons.

Well it needs to stay reversible. As this house is a rental. (Though I've been renting it for 5 years now, and will probably do that still for another 5).

And I want to avoid damaging the board to much. As far I can tell the traces lead through a series of resistors and then back to the ATMEL chip, which is nearly the same as a arduino chip. Though hooking up some wires to the buttons would be the easiest way of hooking up an arduino to it. So the arduino only closes the circuit of said buttons and can deal with the WiFi commands. And just let the original remote do the work its supposed to do.

[Stefan1024]

On 14.5.2017 at 6:02 PM, Aelita Sophie said:

Lets explain the situation first. I've got an airventilation system in my house. Currently there is 1 remote controller that works through RF to control the system. Though I like to make my home smart. I took it apart to see what I was dealing with. Appearently I'm working with a CVE ECO RFT. It's a 2010 model I believe but that doesnt really matter. I've found an article that explains how to reverse engineer the signal and recreate it through an arduino and a RF transmitter on a 868mhz band. That's all fine and dandy, but a bit to overkill for what I want to do. I figure to just desolder the original buttons and hook it up through a relay board with an WiFi enabled arduino. Also taking a buck converter to replace the 3v battery.

I figured I could go the classic Relay or solid state. But for the way I'll be using it, I feel like its a bit overkill. And most important of all, to big. Is there a way to have the same results like a relay, in a smaller package?

 

Link to the article as refference; http://www.progz.nl/blog/index.php/2014/12/reverse-engineering-remote-itho-cve-eco-rft-part-2/

for emulating a switch, you can use the smalest solid state relais you finde (and you can solder). Or you can use a reed relays.

 

With voltages < 30 Volts and currents < 50 mA (and you are far below both), even the most compact relays can handle it.

 

I used this two smal relays two years ago:

 

9x5mm reed relays: CRF05-1A: http://www.mouser.com/ds/2/262/datasheet_reed_relay_CRF-773631.pdf

3.3x2.2mm solid state relays: gmvm-41pr12: http://www.symmetron.ru/suppliers/omron/files/pdf/omron/g3vm_41pr12.pdf

 

As we needed a good frequency responce and low capacity, we where limitted. But there are even smaler once...

[Aelita Sophie]

2 hours ago, Stefan1024 said:

for emulating a switch, you can use the smalest solid state relais you finde (and you can solder). Or you can use a reed relays.

 

With voltages < 30 Volts and currents < 50 mA (and you are far below both), even the most compact relays can handle it.

 

I used this two smal relays two years ago:

 

9x5mm reed relays: CRF05-1A: http://www.mouser.com/ds/2/262/datasheet_reed_relay_CRF-773631.pdf

3.3x2.2mm solid state relays: gmvm-41pr12: http://www.symmetron.ru/suppliers/omron/files/pdf/omron/g3vm_41pr12.pdf

 

As we needed a good frequency responce and low capacity, we where limitted. But there are even smaler once...

The last one seems the most interesting! The question now is, where to get them

[Stefan1024]

8 hours ago, Aelita Sophie said:

The last one seems the most interesting! The question now is, where to get them

Here you are: https://www.digikey.com/product-detail/en/omron-electronics-inc-emc-div/G3VM-41PR12(TR05)/Z3667CT-ND/3711659

 

But they are super expensive, you better get an other one, like this one:

https://www.digikey.com/product-detail/en/ixys-integrated-circuits-division/CPC1017NTR/CLA233DKR-ND/1212887