Weekly Update: May 27, 2017

So, this one’s a bit late. I apologize. It’s been a long weekend at my primary job and it’s worn me out.

On the plus side, that’s now over, AND I have three days off this week. Once my DigiKey order arrives, I’ll be able to hop into some more testing. And speaking of testing – A major landmark in this past week! I managed to upload code to the ESP-12 on the new board. It looks a bit funky, as I had to horridly cobble on some headers into places where they were never designed to be in order to bypass the CP2102 chip, but it worked.

Look at those horridly-cobbled-on headers!I also soldered on the SD card slot, and that worked mostly flawlessly too. The test program picked up the SD card and files just fine, and while a separate one didn’t I’m not too bothered. The SD card is also much easier to remove, unlike the first prototype where it was incredibly difficult. As you can see, it’ll have to be moved to the side some to allow for proper access to the mount hole, but that’s a minor issue.

However, I ran across two issues when attempting to put the rest of the devices on the badge: One, I forgot to order the 1% resistors for the buttons (Oops…), and two: It now isn’t uploading any more programming. I’m not entirely sure at which point the uploading failed, so I’ll have to go back through step by step and test things as I go to see where things went wrong.

Additionally, I discovered an issue in the way the voltage regulator(s) were set up. While they seemed to be functioning (I only managed to test the USB regulator), they wouldn’t stay on even when the ESP was programmed to keep them on. So I’ve begun looking at ways around this issue. Currently, I’m poking through a design that uses an ATTiny running directly off of the battery or USB power (Yay diodes!). The ATTiny can be run as an I2C slave, meaning no extra pin usage on the ESP-12 – In fact, what would have been the power line would now be a free GPIO line. I’ve done some testing with the ATTiny85V that I have and it looks good so far. The ATTiny85V has just barely the number of wires I would need, though, and for curiosity’s sake I looked into the ATTiny84. The 84A has 11 I/O pins to the 85V’s 5, and was actually slightly cheaper on DigiKey. I sent a request to the PCB Manufacturer to get the price of the 84 to see if they can acquire it at a similar price. Additionally, if I use the 84, I could potentially drop the digital potentiometer and drive the backlights from the 84. The digital potentiometer isn’t extremely expensive, but being able to offset the additional price of the 84 some would be great.

I have a DigiKey order that I’m waiting on that has a few 84s to experiment with along with the 1% resistors. I’ll be designing a new PCB to get prototypes of once I have a few more things figured out and adjusted, as there are a handful of things that didn’t line up on their footprints quite so nicely.

If you want to yell at me for being extremely late with this update, you can find me on Discord, on Twitter, and/or Facebook.

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