I have provisions for going directly to the serial lines on the boards I'm designing so I can reprogram them after they are soldered in, but if they are defective? They would be a pain to desolder without risking the board.
So, I needed a fixture to test and initially program the modules - they probably will never change, but better before soldering them down.
There was already someone that did something similar:
Byron's Programmer (fixture)
He has even created a programmer so he can change the firmware. But I couldn't find my pogo pins
At JoAnn fabrics and crafts and probably many other craft stores they have "Sculpey" which is like modeling clay but hardens in any oven. There are probably other similar plastic that can harden in the oven. I thought about some other materials, but I needed something that would be hard so the pins wouldn't move or wear bigger holes.
I had some already, and also got my favorite probe tool, the beading needle. They can go through most insulation when you need to see signals where there is nothing otherwise exposed.
So I put one of the modules down on a flattened mount of Sculpey, placed the flash LED and the needles so they would not short (including inside the sculpey) but also make contact - they are at an angle and I pushed them inward slightly after I removed the bluetooth module. Then it was bake at 275 for 15 minutes. It became hard and solid. I tried some foam core stuff, but it gets pushed and the holes get big so everything gets sloppy after one or two units. I was able to do both an HC_05 master (including the force to 38400 baud mode with the pin on the LED side), and an HC_06 using a 3.3v FTDI breakout from SparkFun normally used for Arduino Pros
Its better to avoid cheap standard Bluetooth modules as it can't transfer and their is a lot of delay in data transfer.
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