Who would have thought that some day we’d need programming jigs for our light bulbs? But progress marches on, and as there’s currently a number of affordable Internet-controlled bulbs powered by the ESP8266 on the market, we’re at the point where a tool to help update the firmware on the light over your kitchen sink might be something nice to have. Which is why [cperiod] created this programming jig for AiLight smart bulbs.
Flashing the AiLight bulbs is easy enough, there’s a series of test points right on the face of the PCB that you can hook up to. But if you’re updating more than one of them, you don’t want to have to solder your programmer up to each bulb individually. That’s where the jig comes in. [cperiod] says there are already some 3D printed designs out there, but they proved to be a bit finicky.
The design that [cperiod] came up with and eventually milled out on a 1610 CNC router is quite simple. It’s effectively just a holder to keep the five pogo pins where they need to be, and a jumper that lets you toggle the chip’s programming mode (useful for debugging).
The neat trick here are the “alignment pins”, which are actually two pieces of 14 gauge copper wire that have had their ends rounded off. It turns out these will slip perfectly into holes on the AliLight PCB, ensuring that the pogo pins end up on target. It works well enough that you can hold the bulb and jig in one hand while programming, it just needs a little downwards pressure to make good contact.
If you have a microcontroller to program, it can be an easy enough process to hook up a serial lead and perform the task. If however you have hundreds of microcontrollers on PCBs to program, connecting that lead multiple times becomes an impossibility. In manufacturing environments they have pogo pin jigs, an array of spring-loaded pins carrying the programming signals that line up perfectly with the appropriate pads on a PCB places on top of it.
[Conor Patrick] is working on an upgrade to the U2F Zero 2-factor authentication token, and he faces exactly this problem of needing to program a lot of boards. His pogo pin jig is very nicely executed, and he’s taken us through his design and manufacture process for it.
Starting with his PCB design in Eagle, he exported it to Fusion 360 in which he was able to create a jig to fit it. Into the jig model he placed the holes for his chosen pogo pins in the appropriate places, before printing it with an SLA 3D printer. He is particularly complementary about the pins themselves, a solder bucket design that comes from mill-Max, and was sourced via DigiKey.
The proof of the pudding is in the eating, and happily when his completed jig received its first board, everything worked as planned and the programming proceeded flawlessly. We’ve shown you other pogo pin jigs, but this one is particularly nicely executed.
The various development boards such as the NodeMCU or Wemos D1 make working with the ESP8266 an absolute breeze. If they have a downside, it is that they are larger than the bare ESP2866, and of course cost a bit more. Just as with the Arduino, once you have the wiring sorted out and the code more or less finalized, your best bet is to ditch the unnecessary support hardware and use the bare module to save space and money in your final design.
Unfortunately, the ESP8266 form factor isn’t terribly forgiving when it comes time for hooking up a programmer. Rather than having to solder a serial adapter to the chip to flash it, [Ryan] came up with a slick 3D printed programming jig that uses pogo pins. If you have to program these boards in bulk, a jig like this can save a massive amount of time and aggravation.
Beyond the 3D printed holder for the pogo pins, this programmer uses a FTDI USB-to-serial adapter, a couple passive components to smooth out the power going into the chip, and a couple buttons.
In the video after the break, [Ryan] walks through the many iterations it took to get the 3D printed aspect of the jig worked out. The design went through a few rather large revisions, including one that fundamentally changed the whole form factor. Even with the jig now working, he mentions that he might circle back around and try it from a different angle.