The purpose of this project was to modify the original TurboCAN board to support additional GPIO pins, which would be used to control the LEDs. A simple change, but it required a full change in the board layout. I took advantage of this to straighten out traces, fix some minor errata in the previous board, and switch to cheaper components where possible. The updated design would have cost about US$30 each, including the STM32 processor, which alone accounted for a quarter of the total price.
I sent off a batch of five boards to be manufactured, and two to be populated by JLCPCB. About six weeks later, when they arrived, they were defective. Manually testing connectivity nets suggested that the manufacturing was accurate, and the USB connectivity worked when tested. However, I was not able to power these off the 24V inlet, and any attempt to do so released magic smoke from the 5V regulator assembly. Despite further testing (and consulting with some other hobbyists in CMU), I was unable to track this error down. The most interesting test we tried was to cut traces on the board, power it up section-by-section (for a second at a time!), and attempt to bisect the error. Unfortunately, this failed when the regulator caught fire. I still haven’t figured out the underlying issue with the design.
Luckily, Mellow released their FLY-SHT42 at around that time, so I just purchased one and used it for my Voron.