Category Archives: Projects

Arduino: running hard to stand still

Don’t you hate it when something that was working stops? You can safely bet that it’s because, somewhere along the way, something has been ‘improved’. I needed to make a change to the code running on a couple of IoT room thermometers. These are built around the Adafruit Huzzah ESP8266 board (the non-Feather version). And they’ve been running flawlessly for months…. Read more »

IR remote control for the home – part 3

In the previous two posts, we set up an ESP32 development board with an IR receiver to read codes sent by a remote control. Now it’s time to add MQTT capability. I chose the PubSubClient library – available in the Arduino IDE library manager – because it claims compatibility with the ESP32. When I looked closer, it turns out that… Read more »

IR remote control for the home – part 2

In the first part, I outlined my plan to build an infrared receiver to act as a hub for IoT devices in the home. Here, we’ll take a closer look at house the receiver works. Here’s what is required for this initial stage of the project: An ESP32 development board. I’m using a DOIT device, which costs around $14. A… Read more »

IR remote control for the home – part 1

How many remote controllers do you have in the house? One for the TV, one for the DVR, one for the Blu Ray player… There are five remotes sitting on the coffee table in our living room. Plus another couple scattered around the house, controlling table lamps and other TVs. And do you know what? This post isn’t even about… Read more »

SmartParallel: Go code is go

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Success! The Go code I’d been struggling with is working, although it also required changes to the C++ code running on the ATMEGA328PB. Here’s a quick overview of how the process works. On the SmartParallel, the ATMEGA328PB code sits in a loop watching for incoming data on the serial port. It also monitors the state of the printer by frequently… Read more »

SmartParallel: n steps back, n+1 steps forward

The principle of ‘one step at a time’ is very sound. The more changes you make at once, the more places there are for bugs to hide. And that’s why this project has been progressing slowly – or not at all – just lately. Finally, though, I feel like it might be back on track. A quick recap: SmartParallel is… Read more »

Homebrew 6502: a new way to start

My Zolatron 64 homebrew 6502 computer project has stalled of late. But it is high on the list of things to restart once I get current projects out of the way. And a recent development has inspired me to look at it again. If you’ve been here before, you’ll know that my plan was to first build a kit –… Read more »

ESP8266 IoT room thermometer – part 4: the code

In response to a flood of requests – well, okay, one – I’ve posted the code for this project on GitHub. But don’t expect to be able to run it. That’s the thing about a maker project – you can create it to be used by anyone who cares to download your designs and code; or you can optimise it… Read more »

SmartParallel: serial shifter issues

I was pretty pleased with my serial level shifting board – right up to the point where I tried to use it. The tl;dr version of this post is that the board works, but not well enough. It has severe limitations that, I think, make it useless for the intended purpose. Let me explain… Voltage levels The purpose of the… Read more »

SmartParallel: laying out the PCB

We’ve been here before, but now it feels like we’re finally getting somewhere. The long-running saga that is my SmartParallel serial-to-parallel dot matrix printer interface is nearing completion. Well, maybe. Having solved (I think) the back-powering problem, and with a prototype that I believe actually works, I’ve decided to call Rev 2.0 of the design schematic the final version. All… Read more »

DIY joystick for the BBC Micro – part 6 – completed (definitely)

Just when you thought it was over… When we last saw this project it was complete except for stuffing the joystick into some kind of box. As that kind of mechanical stuff doesn’t interest me greatly (and I’m crap at it), I wasn’t going to bother with a post about this final step. But hey, I’m nothing if not a… Read more »

SmartParallel: curing the back-powering problem

And so back to the back-powering problem on my ever-imminent SmartParallel interface board. The issue is that, when the printer is powered on but the SmartParallel board isn’t, voltages coming from the printer via signal lines being held high are part-powering the board. One option was to simply ignore this problem. I find that works for a lot of things… Read more »

DIY joystick for the BBC Micro – part 5 – completed (pretty much)

Having got impatient waiting for my PCBs to arrive from China, I went ahead and cobbled together some interim solutions for this project. And what happens? The PCBs arrive the next day. These are the ‘fixed’ PCBs with the proper footprint for the DB15 connector. And what can I tell you? They work. There is one slight issue that I… Read more »

DIY joystick for the BBC Micro – part 4 – a quick lash-up

While waiting for revised PCBs to arrive from China, I figured the time would be well spent learning a little more about the BBC Micro’s analogue port. And I have taken delivery of a couple of DB15 breakout boards, which meant I could try wiring up the joystick, albeit in a crude and temporary way. One joystick needs to send… Read more »

SmartParallel: mystery solved

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Although the stripboard version of the SmartParallel board is working, one niggle remained. When the printer was switched on, but the SmartParallel board wasn’t powered, I was getting random resets of the printer. They weren’t as frequent as with the breadboard prototype, but they were there, sometimes. Also, there was a problem with signals effectively ‘back powering’ (I’m not sure… Read more »