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I'm trying to make a DIY smart socket. Is it possible to control the relay with an Arduino? Maybe replace the controller with the Arduino?

Can I use the ribbon cable Out, Ground and VCC pins do to that? Model: EMT757

The Timer Controller Board With the OUT pin, VCC and GND:

enter image description here Relay board where the VCC, GND and OUT go from, the controller:

enter image description here

enter image description here

Behind the relay board: enter image description here

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  • \$\begingroup\$ No schematic = no answer. \$\endgroup\$ – Jakub Rakus Nov 28 '18 at 16:47
  • \$\begingroup\$ @JakubRakus where can i find them? \$\endgroup\$ – articga Nov 28 '18 at 16:48
  • \$\begingroup\$ You can try and reverse engineer it. From looking at the fotos it's a non isolated capacitive dropper supply with small battery backup feeding gnd and vcc while out controls the transistor that switches the relay. \$\endgroup\$ – ratchet freak Nov 28 '18 at 16:52
  • \$\begingroup\$ @articga Probably you can't, only manufacturer have it. This is reverse engineering task, You just have to draw schematic yourself. \$\endgroup\$ – Jakub Rakus Nov 28 '18 at 16:53
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A simple google search has yielded a schematic for the relay section: https://drive.google.com/file/d/0B43XXiSt0MIdem9TcjBDNUNhcnM/edit Schematic

Credit for the schematic goes to Adrian Jones

To answer your question, yes, the ribbon cable can be used, but you will have take a couple of things into consideration:

  1. NOT ISOLATED FROM MAINS
  2. Assuming that you have not electrocuted yourself, you will have to change the value of the 4k7 resistors and zener diode, to match the voltage you require and the current consumption
  3. Remove the battery ifyou don't want it to blow up if you are using a higher voltage than 1.2V of that cell
  4. make sure that the diode bridge is rated for the current you require.

Again be aware, it can be 1.2V at the output, but you are NOT isolated from mains

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    \$\begingroup\$ I didn't follow the link but if it's a schematic then it should be posted inline in the question so that the information is still available when the link dies. \$\endgroup\$ – Transistor Nov 28 '18 at 18:00
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    \$\begingroup\$ I soldered the output from a Raspberry Pi GPIO pin to the ribbon cable OUT on the relay board and Raspberry Pi ground pin to the GND on the relay board and cut off the stock timer controller. I removed the VCC pin. And it does work when turning on the GPIO pin. Is the method safe? \$\endgroup\$ – articga Nov 28 '18 at 19:14
  • \$\begingroup\$ It is safe as long as even the RPi is in a box and it is completely isolated from the outside world. I would do as in the picture above and put an optocoupler, but connecting the Collector of it to the control pin instead. \$\endgroup\$ – Elmesito Nov 28 '18 at 19:19
  • \$\begingroup\$ I used a power bank to power the RPi before, is it safe to plug it into the wall? \$\endgroup\$ – articga Nov 28 '18 at 19:24

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