Electronics

This article is about using an I2C analogue-to-digital device for applications like reading sensor values or monitoring backup batteries. With all the technical bits left in.

Categories: Raspberry Pi, electronics, embedded computing, C

This article describes how to do simple temperature measurement with a Raspberry Pi, and I2C analog-to-digital converter, and a thermistor.

Categories: Raspberry Pi, electronics, embedded computing, C

AC circuit analysis relies heavily on complex numbers, and the concept of 'complex impedance'. But why? What actually is a complex impedance?

Categories: mathematics, electronics

The use of dithering when mastering a CD is well-established, and its effectiveness is rarely challenged. But is it beneficial in other circumstances when we need to reduce the bit depth of an audio stream?

Categories: hifi, electronics

You'd think you could improve the cooling of a laptop by fitting extra fans under its air intakes. Seems not.

Categories: electronics, general computing

On websites, and in hobbyist kits for Raspberry Pi and Arduino, you'll often see I²C devices connected that have different supply voltages. This is (usually) safe and, in non-critical applications, tends to work. But why?

Categories: Raspberry Pi, electronics, embedded computing, Pico

A mains inverter is a very useful device, but inexpensive models create significant electrical safety hazards. This article explains why.

Categories: electronics

Some thoughts on my first experiments with the design of electronics enclosures for laser cutting.

Categories: Raspberry Pi, electronics

Using a single MOSFET transistor for power switching in microcontroller applications is simple and low-cost, but it often doesn't work as well as expected. Either the switched device doesn't run at full capacity, or the MOSFET gets hot. This article explains why.

Categories: Raspberry Pi, electronics, embedded computing

Why an expensive smart watch is still less good than a cheap Timex, when it comes to telling the time.

Categories: electronics

It's surprisingly difficult to detect switch actuations in a robust way, dealing with contact bounce and other quirks. This article describes one approach to the problem in C.

Categories: Raspberry Pi, electronics, embedded computing

The Raspberry Pi has a bunch of GPIO pins we can use to connect push-buttons. But how do we interface push-buttons to an application that expects only keyboard input?

Categories: Raspberry Pi, electronics, Linux

Switching loads of an amp or two with a Raspberry Pi or a microcontroller can be accomplished using a small number of inexpensive components. Suitable circuits are widely published, but the details of operation are not always described.

Categories: Raspberry Pi, electronics, embedded computing

Attaching high-capacity hard disks has always been a bit of a problem for the Raspberry Pi. In this article I describe a simple modification to a Waveshare USB HAT, that allows it to power both the attached drives and also the Pi itself.

Categories: Raspberry Pi, electronics

This is a design for a robust, wooden enclosure for a Raspberry Pi, battery power supply, and touchscreen, that can be made using hand tools.

Categories: Raspberry Pi, embedded computing, electronics

A specific application of the Pico7219 library that I described in an earlier article.

Categories: embedded computing, Pico, electronics

The L298N is a convenient and inexpensive H-bridge motor controller, which interfaces nicely with the Pi Pico.

Categories: electronics, embedded computing, Pico

No 80s computer is complete without the chucka-chucka-chucka sound of a floppy disk drive doing its thing.

Categories: electronics, Z80, retrocomputing

Using an RC2014-based retrocomputer with genuine RS232 peripherals requires support for voltage level conversion. Although converter modules are inexpensive and widely available, I wanted to design something that would plug into an RC2014 backplane, just for neatness.

Categories: electronics, Z80, retrocomputing

Constructing and programming a real-time clock board for my Z80 CP/M system

Categories: C, electronics, Z80, retrocomputing

An 80's-style 8-bit computer has to be cable of making 80's 8-bit sound. In this article I describe adding a sound board to my RC2014 system.

Categories: electronics, Z80, retrocomputing

This article describes a couple of methods for sharing data and code between a CP/M system with RomWBW BIOS and a Linux system.

Categories: C, electronics, Z80, retrocomputing

It's common for hifi amplifiers and speakers to have a power rating expressed in terms of RMS watts. Although RMS amplitude is an important concept in electronic engineering, it's meaningless here, and should be avoided.

Categories: hifi, electronics

The official Raspberry Pi 7-inch touchscreen is a useful and well-designed piece of equipment but, if you're using it in a custom (hardware and/or software) build, you'll notice a lack of any relevant technical information. This article tries to supply some of that information.

Categories: Raspberry Pi, electronics, embedded computing

The Raspberry Pi is widely used as part of a more complex electronic project or construction. There's a misconception that such a construction can be powered from the same cheap, nasty USB charger that is suitable to power a Pi on its own. Attempting to do this often leads to undervoltage situations. This article explains why, and what constructors can do about it.

Categories: Raspberry Pi, electronics, embedded computing

Hi-fi snobs and complacent manufacturers colluded to rob us of our tone controls in the 90s. Why should we care?

Categories: TDMTLTAM, electronics

Vintage vinyl records ought, perhaps, to be played on a vintage turntable. Although such appliances are still widely available, and can work well, they fall short of contemporary electrical safety standards.

Categories: electronics, hifi