Keyboard Builders' Digest / Tools
Bonsai C3 is back!
Check out the Bonsai C3, a Proton C replacement by CustomMK. Back in stock after the chip shortage, kbd.news readers can get it for a special price now.
Published July 20, 2023
First come, first served: A limited stock of Bonsai C3 controllers is available for $12.99 for kbd.news readers (use the KBDNEWS discount code)!
Remember the Proton C development board? And how it has been perpetually out of stock for the past few years due to the great microcontroller shortage? I bring you great news: it's back, and even better!
During the microcontroller drought, David at customMK designed a fully-equivalent and open-source version of the Proton C called Bonsai C3:
Bonsai C3 is a high performance drop-in replacement for the Pro Micro. It is functionally equivalent to the Proton C with STM32F303CCT6 ARM microcontroller, USB-C, 256kB program memory, audio speaker, etc.
However, the chip used on Proton C had been so difficult to obtain that in 2021 it cost David almost $50 for a single STM32F303CCT6 to test the Bonsai C3 design! Even just a year ago in 2022 the part cost $22 each in quantities of a few hundred. But then earlier this month, David noticed that JLCPCB had a few thousand of the microcontrollers in stock at a reasonable price, so he produced 100 Bonsai C3 which are now available at customMK.
He also provided me with an exclusive coupon code (KBDNEWS) which will save you an additional $3, for a final price of only $12.99 per Bonsai C3!
Because there are only 100 available, they may sell out rather quickly. If you happen to miss out and want to be notified as soon as another batch becomes available, you can subscribe to the kbd.news newsletter and we'll let you know as soon as he makes more of them – maybe with a special discount code again too.
If you're like me and you need a refresher on differences between some of these microcontroller boards, here's a brief comparison:
There is one notable difference from the original Proton C: Bonsai C3 actually includes the speaker pre-installed. If you don't want the speaker hooked up for some reason, it's very easy to remove with a soldering iron, or you can also snap off the lower portion of the board entirely.
Resources
Published on Thu 20th Jul 2023. Featured in KBD #128.
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