Mounting the Wemos D1 Mini
I use the Wemos D1 Mini for all of my wifi based projects, such as the remote control Strandbeest and the Stranger things light board. It's a powerful little board that exposes the ESP8266 via a USB to Serial converter and it can be set up to run from the Arduino environment. It's also really cheap and can be bought for less than $2.50 so if you want to make something remote controlled it's a bit of a no brainer. The trouble is that the board doesn't have any mounting holes so it can be hard to attach to a project.
While looking to affix my board securely to my projects I realise that there was a gap to the left and right of the ESP8266, either side of the antennae that didn't appear to have any copper or tracks running through the area. The board is only a 2 layer design so it should safe to drill directly through the PCB and use this as a solid fixing point. A quick test later on a sacrificial board showed that this was indeed possible and although adding screws next to the antennae may restrict the maximum range, the maximum distance I require is 25m and it seems to still run fine. I used a 2mm drill bit to make the holes and I routinely use M2 x 6mm machine screws to fix the boards to my projects.
Once some suitable mounting holes were identified I had the problem of drilling holes in dozens of boards for my kits. I've talked about jigs a lot before and this is no exception, making a jig to hold the boards in place and show me where to drill the holes is the best way to ensure each board will fit into any kit. It's also the fastest way to drill 100 boards in a single sitting.
I started off with a single board design, by flipping the wemos upside down and I can use the ESP8266 board and metal can to align it into the jig. This ensures that even if the ESP board is slightly offset the holes will still be equally spaced on either side of it. I scaled my jig to eventually hold four boards at a time, allowing me to drill more holes between changing boards over. I'm sharing the files for the jigs so that other people can drill similar mounting holes should they need them (svg here) (dxf here)
Here are some assembly photos for the 4 board jig, I added some feet onto the bottom using scraps of wood but I have now included some feet into the spaces cut from the jig.