Convertor/PSU - 230V or 12VAC terminals down to 5V USB

Other Hardware General Electronics
1

I'm fitting an ESP8266 Wemos to my alarm panel, and space is limited inside the panel. I can't get access under normal running conditions.

So I would like a way to power my Wemos from 230V mains supply / or the secondary 12V AC

Can anyone suggest a compact solution?

Looks something like this:
(far right terminals labelled 13, note not my photo's)

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Requirements:

  1. To be able to connect with cables to the 230V mains / 12V AC terminals of the alarm panel
  2. To supply nice clean 5V supply.
  3. Ideally would have USB/micro USB connector
  4. If no USB connector, I would need to modify a small micro usb cable myself and connect to pins 1 & 5

Thanks :slight_smile:

2

Your alarm has a nice clean 12v DC supply in it , use that and a step down converter to 5v.

3

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:slight_smile:

4

hammy:
Your alarm has a nice clean 12v DC supply in it , use that and a step down converter to 5v.

Cheers hammy,

Yes I was just thinking about that. I was avoiding it at first as it might be too much load on the alarm board. But I'm guessing the Wemos pulls very little milliamps, will have to check.

I was going to have a backup 18650 2200mAh battery. But that battery would then probably not be required, as the alarm has a large backup battery of it's own.

Seems win win :slight_smile:

septillion:

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:slight_smile:

A little bit too big, plus there's not a socket in there :slight_smile:
I think hammy has a winning idea!

5

877:
But I'm guessing the Wemos pulls very little milliamps, will have to check.

I would not guess to hard... Wifi is pretty power hungry!

877:
A little bit too big, plus there's not a socket in there :slight_smile:

Big!? Really, you are not getting it any smaller! Not safely from mains anyway. And no socket isn't a problem, just solder wires + shrink wrap around the prongs.

6

septillion:
I would not guess to hard... Wifi is pretty power hungry!
Big!? Really, you are not getting it any smaller! Not safely from mains anyway. And no socket isn't a problem, just solder wires + shrink wrap around the prongs.

Hmm yes seems you are correct, I just read a figure of 800mA! So that could have significant issues as I think the alarm panel have quick blow fuses rated at 1A :slight_smile:

Yes I suppose it it not 'too' big considering, I am from the UK actually but could find an equivalent for 230V.
Thanks septillion :slight_smile:

PS if I don't reply soon it because I am still capped every 5 mins :sob: :wink:

7

Yeah, was the first image I found. Okay, a UK one probably is a bit bigger but a normal EU one is pretty small. You could also remove it from the case but that would mounting it a bit more challenging because the lack of isolation that way.

Other thing I thought about was the battery itself. If that's connected common GND and the charge current is more than the average Wemos current you could just use that :slight_smile: But yeah, that would require a (DCDC) voltage converter. But again a simple part:

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of which you can use the guts.

8

septillion:
Yeah, was the first image I found. Okay, a UK one probably is a bit bigger but a normal EU one is pretty small. You could also remove it from the case but that would mounting it a bit more challenging because the lack of isolation that way.

Other thing I thought about was the battery itself. If that's connected common GND and the charge current is more than the average Wemos current you could just use that :slight_smile: But yeah, that would require a (DCDC) voltage converter. But again a simple part:

1400×1400 38.6 KB

of which you can use the guts.

Good idea, I will dig out the alarm manual and have a look at the specs, I have a few of those car type convertors around. Cheers :slight_smile: