Recently, I’ve been testing some HM10 and HM11 Bluetooth Low Energy modules for a BLE beacon project.
But the problem with these BLE modules is that they come as a bare board, hardly bigger than a postage stamp, which is great for deployment but terrible for testing, as they have 1.5mm spaced connectors on the side, rather than the traditional 1/10 inch.
Anyway, I thought I’d share my simple solution to connecting them to a $5 USB to serial adaptor.
All you need is a single in line socket, which are readily available from multiple suppliers on eBay etc, as they are used when making Arduino shields.
The trick is to use a socket with the same number of pins as the USB 2 serial adaptor, so its hard to plug it in the wrong way around.
Firstly, you need to glue the socket to the back of the HM10 module. I use a hot glue gun, but any reasonably strong glue will do.
Then its just a question of cutting the pins on the inline socket to the appropriate length, (around 2 or 3 mm long is idea), and use some fine gauge wire (I use wirestrip wire), so connect the 4 necessary connections, GND, 3.3V, TX and RX from the inline socket to the pins on the HM10
You can then simply plug the module into your USB to serial adaptor when you need to program it via the PC
The chances of plugging the HM10 around the wrong way, are quite low, as the are 6 pins on the usb to serial adaptor and the socket is 6 pins, so all you need to remember is to put the HM10 chip side up like the USB to serial adaptor.