Aqara are one of the few manufacturers producing affordable, well built, Zigbee “compatible” light switches that are both available in my part of the world, and suitable for local electrical installations. Aqara are a brand of Xiaomi-backed Lumi United Tech.

Full SWD/JTAG debugging is great wherever possible, but sometimes it’s not available, or a device is being tested in a production environment, or is perhaps in production.

The NXP Zigbee SDK is not well setup for use with C++. Although I prefer it over the Texas Instruments ZStack for various reasons, ease of C++ development is not one of them. I had no trouble converting ZStack sample programs to C++. I had all sorts of issues with the NXP SDK.

My attempt to develop custom firmware for the Aqara E1 Zigbee wall switch necessitated learning NXP’s Zigbee SDK for the JN5189.

A comprehensive list of major Zigbee IC vendors and module makers, including a matrix of which module maker use which vendor's ICs.

How to configure an ATMega328p to consume lest than 1uA, while still retaining the ability to wake the processor up periodically via timer (or external interrupt).

Discussion of the design and implementations problems encountered during the design/construction of my in-wall Bluetooth audio player, with environmental sensors, proximity wake-up, metadata display, and cat animations.

Firmware design for the Bluetooth audio player project. The basic architecture uses events to trigger external interrupts. Handlers post the event details into a queue and a simple control loop polls the queue and dispatches events to various handlers.

Circuit and PCB design for the Bluetooth audio player project. The circuit design is not complicated. The main sections are MCU with 8MHz crystal and supporting caps, ...

My latest project is a cat-themed Bluetooth audio player to be permanently installed in my bathroom. The unit will be housed in a standard electrical junction box on the bathroom wall..

STM32 microcontroller cheat sheet by product line, feature, model number. Includes product code descriptions and timer/peripheral information.

Continuing on from the prior posts on the controller hardware and manufacturing, the device needs software.

So far we’ve looked at the hardware design, but aside from modifying the oven in part 1, nothing has been built yet.

In part 1 we discussed the selection and modification of the oven itself. It’s now time to work on the external controller.

After reflowing for some time with hot air and saucepans, I’ve decided it’s time to build a dedicated reflow oven. There are tons of DIY reflow oven projects out there, but I decided to design and build my own (see NIH syndrome) for the fun of it.

Building an automatic water manager for a vertical garden wall.