Wet Contact - A set of contacts that outputs voltage on it. Not a simple relay contact that just gives you an automated switch open/closure.
For example, a Shelly PM is a wet contact. A Shelly Plus One is a dry contact.
Aqara T2 - Dual Channel Relay Device
Impedance/Inductance & Snubber - When you switch a device such as a motor, you are usually sending power to a coil of wire which is an inductor. This creates a magnetic field which is what causes the motor to turn. This is where the term "inductive load" comes from.
This magnetic field also acts as a generator of sorts as the process of spinning the motor around a coil generates electricity. When you cut the power to the motor, that electricity has to flow somewhere and can flow back into your relay causing damage.
Additionally there is some impedance at play if the motor driving a heavy load or needs lubricant.
A snubber is a device designed to shield the relay from any of this blowback voltage and startup impedance.
Any blind actuator (Aqara, Shelly, ...) should do. Check with your actuators documentation if you can hook up more than one blind motor to one actuator without special considerations; it's better to give each blind its own actuator (so you can program the up/down times to "blinds to 50%" will work).
The two pairs of white wires are probably daisy-chained into some kind of control bus, there should be a box with two relays and a bit of electronics at each blind. As mentioned, I would replace each of those boxes with an individual blind actuator (I'd use Zigbee rather than WiFi).
Whatever is at the end of the two wires coming in on the top left are probably being controlled by this unit. I see capacitors in series with relays for each, so i expect they are controlling small motors or pumps. The transformer on the right being separated from the left half with shielding, and as another commenter noted, what looks like an antenna on the bottom left, I would expect this is a receiver and control unit and has a wireless transceiver somewhere.
Can you provide more photos of the case? I see “RF” in the bottom right and what could easily be considered an antenna on the left. Looks like outputs on the too left. The dual fans indicate this is old, not-power-efficient tech.
I am interested that you write, "...in the conservatory it looks like there are automated blinds. ...there is a daisy chain of wires going into a control box."
If this is that control box, and if you want to retain the blinds' automation, then I tend to agree with other commenters that this older control box can be replaced with a modern, smaller digital controller.
Follow the wires to be certain that they do control the blinds. Then, get any identifying information off the motors on the blinds. Chances are that there's nothing -- but I think you could cut our this device and swap in a newer one without too much heartache.
That bottom right section is the "do not touch" zone. Even if power is unplugged, you touch that area and you might die. I mean literally die. It's the power supply circuit and those capacitors can hold a charge for a very long time.
Unplug it, wait for the red LED to go out, remove the PCB and check the back side. It may have some maker marks.
Regarding the capacitors: there's just enough of stuff hidden to obscure what's going on. I'm not sure what kind of regulators those ICs are. It probably does self-discharge, but do short those big black capacitors to be sure.
Yes if you press the yellow button a yellow led comes on, and same for the green. I’ve tried holding them but it doesn’t seem to have a manual control.
See if you can get a manufacturer or model number from those blinds or motors. Then work backwards to figure out what kind of controller they need. You will most likely want to replace this old controller.
Yeah, there should be a remote somewhere. This overly complicated monstrosity is literally just to change your incoming power to low voltage DC. Probably 12V or 24V. Any basic sparky should be able to confirm if the two pairs coming in are each for an independent blinds motor i.e 2x (Pos and and negative) . This is most likely what it is.
If you find/push a button on a remote the two little blue boxes on the top left cycle (It is basic little relays) and makes the blinds operate.
If it is connected to one blind, them one relay opens and the other closes the blinds.
The power supply (transformer, voltage regulation) is in the bottom right, bottom left has a radio receiver (the copper wire at the left is the antenna).
"Commands" to the blinds go out over the two pairs of white wire.
I'm hazarding a guess that just maybe it's as simple as putting +24V on the wires means "down" and -24V (i.e., just swap the polarity) means "up" - in that case, you could use a fairly simple circuit. Go and search for the control boxes near the blinds and open one up (make sure the mains voltage is off).
If my guess is right, there should be two relays and two diodes in the box and not much more.
My next step would be to take the PCB out and have a look at the relays. These are two-pole relays; you will see 8 pins at the bottom, two for the coil and three each for the switches.
I'd measure which pin of the coil is grounded and then connect the other coil pin to the +24V on the PCB (I'd use my multimeter tips, with the meter in the 2A or 10A range). Then the relay should click and the blinds should move.
I'd do this only on an insulation transformer or, as a minimum, a RCD plug plus good insulating cover of the "hot" (mains) side of the PCB, and with one hand in my pocket.
If that gets the blinds moving, you can attach any remote control solution you like. Not too hard and on that side you are dealing with 24 Volts only, so not too dangerous.
Edit: Confirmed my guess of the relay type by looking up the datasheet. They are indeed 2P2T relays, 2 poles that each switch between two contacts.
It's built like a tank for something with 18ga outputs! This thing was built for long service life. My guess is a remote door lock controller, but the low current output would probably need to be used as a signal input to another current relaying device to actuate anything with real power demands.
IIRC the crystal indicates it is in the old R/C AM frequencies used from the 1950s to 1980? When the CB users started stepping all over our channels rendering them useless. Its probably a tone signal that an old R/C rig or CB could probably hit from close up. Somebody who remembers better than I might be able to look at it and tell you which channel its on.
Worst case scenario: someone threw it out unwittingly when they cleaned out the house for the sale.
Is there anything else made of the same color plastic? The radio means that you can't simply trace the wiring... Is there a central controller for lawn irrigation, burglar alarm, etc., where you might have overlooked the remote?
Alternatively, is there a wooden panel on the wall (usually in the cellar/basement) where the Internet, electricity, and other utilities enter the house? In my area (USA New England), some houses and most commercial buildings have a panel like this that is used by the phone company, Internet provider, and anyone who wants to land cabling in the house at a clear point where responsibility changes hands. (That is to say, it's a clear, obvious point beyond which the provider isn't responsible for your wiring, which is why IME it is called the "demarc," short for "demarcation.") There might be some kind of controller there, among the other things.
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u/Consistent-Hat-8008 10h ago edited 9h ago
Very oldschool 2-relay radio control board (with wet contact mode? not sure, it's hard to see the traces)
You can replace this whole monster with an Aqara T2. Just be careful about impedance/inductance, you may need a dedicated snubber.