Powering widgets

Making widgets for the alarm system means that power is quite simple - the alarm wiring has 12V DC, and a simple regulator means I can connect to that - typically with screw terminals.

However, making other widgets with an ESP32, like the environmental monitor, or the Brexit clock, means finding a way to power them. I am not yet playing with battery powered stuff (will do, eventually), so need a power lead.

So what to use?

Initially I tried a micro-USB. Leads for this are very common, and USB-A sockets providing 5V are so common they are fitted to standard power sockets even, so seems ideal.

The issue is the connectors. I have struggled to find what I need. I did see some from China (which have not yet arrived) which have only the power tabs on them making soldering easier, and have clips to hold to the PCB. Whilst waiting for those, I tried some simple surface mount connectors.

The problem is they are not very robust, even superglued to the board, they can become detached very quickly.

I have actually made a set of tools under OpenSCAD two make tight fitting 3D cases to help hold the connector in place, which has helped, but that is still a challenge, and I am not happy about it.

The other catch is the tiny tiny surface mount connectors... Thankfully I only need the ones at the ends. For reference, the three pins at the bottom are 0.1" spaced.

So, I wanted to find a solution, and turned to USB-C. These are a nightmare, not only tiny tiny tiny surface mount tabs, but tabs under the connector so you cannot get to them with a soldering iron. Finally I found a part that will do, and from a UK supplier.

It did mean some fine milling, and even finer soldering, but again, only needing the double connectors at the ends, so just about possible. Those pads are 0.5mm spaced!

The result is a nice solid, soldered to the board, connector.


  1. Which connectors are those? I have been looking at migrating to USB-C too, but finding ones that can be soldered without a full solder paste stencil and reflow is proving rather difficult!

    1. https://www.toby.co.uk/signal-to-board-connectors/usb-connectors/csp-usc16-tr/

  2. Hi,

    I've had success with https://uk.farnell.com/multicomp/mc001667/micro-usb-type-b-rcpt-smt/dp/2759099?CMP=i-bf9f-00001000

    They have a big solder pin on each side and two on the back to secure them to the board. You'll have to drill shallow holes for them that are directly surrounded with copper.


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