ESP32 Forum

I have two motorized door locks. To open they take 12V and the specs say: 250mA max inrush, 10mA max holding.

I have a wESP32. It uses PoE and V+ provides 12V with 12.95+ W of power (1.079A).

What's a good way to have the wESP32 open the door locks? I need to control them individually and at the same time. I think I can run them directly from V+, but I need a way to switch it.

I have some 4 channel optocouplers: LTV-846 (datasheet attached). My understanding is each IC will be in the range of 50-600% CTR. I have 25 and could screen them. I'm a noob, but I think this means if I run the optocoupler LED at 25mA, the best I can hope for with 600% CTR is 150mA on the output side. Is this good enough for the door locks? The 250mA says "inrush" but I'm not sure how the optocoupler would handle that.

If that won't work, can you please suggest parts that would work?

You can use a 12V relay module.

Thanks. True, a ready to use 2 channel module sounds pretty easy. Do you have a recommendation? There are a number of cheap mechanical relays that are easy to find, but I'd like to pay extra for quality and long life. I tried to find a solid state relay, but many have a load rating that is too high, eg 24-240V.

I briefly looked at using a relay directly, that seems to need some supporting electronics and got over my head pretty quick. I could probably figure it out in time, but a module is much easier.

I read a little that an optocoupler could work by also using a mosfet or "buffer". I suppose that's not the simplest way, though it's neat. EDIT: turns out it seems this is what a solid state relay is doing internally!

Can it be done with a transistor? I tried reading up on that but they are used for many things and it's hard to find relevant info.

EDIT: I ended up going with PVD1354NPBF. The output supports 0-100V and 550mA, seems like it should work!

The SSR that you've mentioned can provide 550mA load current. Doesn't your 12V solenoid doorlock have a higher current requirement? Kindly check.

The door locks are motorized rather than using a solenoid. The only specs I have for the door locks are: 250mA max inrush, 10mA max holding.

I've got the SSRs wired up, they seem to work great! Well, I don't have the door locks so I can't test with those (it will be months yet), but the relays are working like they should -- super easy to use. I've used optocouplers in the past for logic level signals, these SSRs seem like the next step. It's really neat to be able to control higher current circuits this way.