Electronics – Made by Mikal

Holman CLXRGB60 RGB WiFi garden light controllers and tasmota

Post author:mikal
Post published:March 25, 2023
Post category:Electronics

Today I went forth to Bunnings in the rain to purchase a Holman CLXRGB60 RGB garden light controller so that I too could have fancy lighting in my garden and impress all those guests I never have over. I had been given hope by the Blakadder site that I would be able to flash tasmota onto the controller so it integrated with my Home Assistant home automation. Unfortunately, it was not to be. Despite the device being TYWE3L based, the warning on the blakaddr site was correct, and this is a next-gen Tuya device where the crypto hasn't been broken yet. Then again, I couldn't even get this device to pair in the Holman app, so it clearly hates me. This unfortunately means the excellent instructions from Jon Oxer were unforunately not helpful today. I think there is a theoretical option here to flash using the serial pins on the board, ala this guide. Also, it means my hair got wet for nothing. So as to take revenge for my wet hair I have decided to pivot. The Holman lights seem quite well made, but they're just 12 volt RGB PWM devices. So I can use their lights and build…

The wonderful world of machine learning automated lego sorting

Post author:mikal
Post published:August 8, 2019
Post category:Electronics

Inspired by Alastair D'Silva's cunning plans for world domination, I've been googling around for automated lego sorting systems recently. This seems like a nice tractable machine learning problem with some robotics thrown in for fun. Some cool projects if you're that way inclined: Sorting 2 Metric Tons of Lego A lego sorter using tensorflow This sounds like a great way to misspend some evenings to me...

Raspberry Pi HAT identity EEPROMs, a simple guide

Post author:mikal
Post published:June 13, 2019
Post category:Electronics Gang Scan

I've been working on a RFID scanner than can best be described as an overly large Raspberry Pi HAT recently. One of the things I am grappling with as I get closer to production boards is that I need to be able to identify what version of the HAT is currently installed -- the software can then tweak its behaviour based on the hardware present. I had toyed with using some spare GPIO lines and "hard coded" links on the HAT to identify board versions to the Raspberry Pi, but it turns out others have been here before and there's a much better way. The Raspberry Pi folks have defined something called the "Hardware On Top" (HAT) specification which defines an i2c EEPROM which can be used to identify a HAT to the Raspberry Pi. There are a couple of good resources I've found that help you do this thing -- sparkfun have a tutorial which covers it, and there is an interesting forum post. However, I couldn't find a simple tutorial for HAT designers that just covered exactly what they need to know and nothing else. There were also some gaps in those documents compared with my experiences, and…

A nerd snipe, in which I learn to read gerber files

Post author:mikal
Post published:May 21, 2019
Post category:Electronics

So, I had the realisation last night that the biggest sunk cost with getting a PCB made in China is the shipping. The boards are about 50 cents each, and then its $25 for shipping (US dollars of course). I should therefore be packing as many boards into a single order as possible to reduce the shipping cost per board. I have a couple of boards on the trot at the moment, my RFID attendance tracker project (called GangScan), and I've just decided to actually get my numitrons working and whipped up a quick break out board for those. You'll see more about that one later I'm sure. I decided to ask my friends in Canberra if they needed any boards made, and one friend presented with a set of Gerber CAM files and nothing else. That's a pain because I need to know the dimensions of the board for the quoting system. Of course, I couldn't find a tool to do extract that for me with a couple of minutes of Googling, so... I decided to just learn to read the file format. Gerber is well specified, with a quite nice specification available online. So it wasn't too hard…