I2CDriver manufacture
The I2CDriver campaign ends in 48 hours. I2CDriver and the I2C modules that go with it are all set to start manufacturing. I've worked with this manufacturer (Boktech in Shenzhen) before, so we're all pretty comfortable with the process. I've sent them a BOM and design files. But the trickiest part of the production for me is making and sending them a test stand. This is the hardware that Boktech will use to check that each part is working, before they ship them to me.
So for each product I make a test fixture that automates the process, and send it to Boktech. I usually only make one, so these are quite special.
First is the fixture for I2CDriver. You push the board down onto some spring-loaded pogo pins, and in about 1 second it loads the I2CDriver with test firmware that runs a self-test. If something isn't right it comes up on the screen in red like this:
The test fixture is quite similar to the one I made for SPIDriver last year. One improvement is that the USB connections are now brought out to pogo pads on the back of the board. This means that the test/program cycle doesn't need a USB cable to be plugged into each unit. It's a small saving, but multiplied by 1000 it really makes a big difference.
The second fixture is much more ambitious. The "extras" for I2CDriver are all custom-made I2C modules. There are 10 different modules, all the same size. They are going to be manufactured in a single PCB which will be split into the individual modules. Each of the ten modules has 4 or 6 pins, depending on whether it has an onboard microcontroller. So the test fixture has 50 pogo pins:
To test the PCB, you have to push it down into the 50 pogo pins. While a single pogo takes a little bit of pressure, multiplied by 50 results in a surprisingly strong force. So here I'm pushing the board onto the pins with three fingers:
The onboard screen shows a map of the ten modules, green for pass and red for fail. As well as testing the modules, it sends out some I2C commands to drive the module's LEDs and buzzer.
Both fixtures are made of laser-cut acrylic sheet, fixed together with M2.5 brass standoffs and M.25 nuts and screws. I'm now using the excellent socketed pogo pins available from Dirty PCBs.
Thanks for reading.