Author Archives: Machina

SmartParallel: hacking a Centronics connector

Okay, I lied. Having ordered the PCBs for my Centronics breakout board, and also having ordered a couple of DB25 breakout boards via Ebay, I settled in for the long wait I knew would follow. I said in an earlier post that I was getting used to these two to three-week delivery times for stuff coming from China. The truth… Read more »

Protip: Buy only female-female jumper cables

Jumper cables with DuPont headers are an essential part of your toolkit. Any dabbler in electronics will have drawers of the damn things – and probably not a few wandering randomly around the workbench. But when the time comes to buy more (where do they go?) there’s always a dilemma. Do you need male-male, female-female or female-male? And how many of… Read more »

SmartParallel: Centronics breakout board

Creating a full breadboard version of the SmartParallel board is turning out not to be a five-minute affair. It has to be done meticulously and methodically if it is to have any value as a prototype. Fitting it all on to a single breadboard is proving challenging too. And that got me thinking. What about replicating at least part of… Read more »

SmartParallel: fixing the PCB layout

Hmm, yes, clearly it wasn’t going to be as easy as all that. While creating the PCB layout for the SmartParallel serial to parallel printer interface, I shuffled a few of the pin assignments on the Atmel ATMEGA328PB microcontroller. The reason was simply to make routing a tad easier. But I had a nagging feeling that this might cause a… Read more »

TTL serial level shifter

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Not every device speaks the same voltage. In designing the SmartParallel serial-to-parallel printer adapter, I chose to use 5V as the VCC supply throughout the board. But I was constantly aware that some of the devices that might talk to the board – such as the Raspberry Pi – use 3.3V for their I/O. What to do? There’s only a… Read more »

SmartParallel: First complete PCB layout

Well that wasn’t easy. Finally, the SmartParallel TTL serial to parallel printer interface has a complete PCB layout. And I learned a few lessons along the way. The most important of these, perhaps, is that when assigning signals to the pins of a microcontroller during the schematic drawing part of the project, don’t rely on whimsy or the luck of… Read more »

Taking flight

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In my series on ‘building’ a PC, I mentioned that a motivating factor was to have a games platform. I think I mentioned Elite: Dangerous and Kerbal Space Program. The truth, though, is that I wanted to play with flight simulators. I first took up Microsoft’s Flight Simulator when it was version 2.0 and running on DOS. I stuck with it through to… Read more »

DIY joystick for the BBC Micro – part 2

In the first part I described the interface between two RJ45 Ethernet sockets and the BBC Micro’s analogue port. The idea behind using RJ45 connectors is that you can use any old Ethernet cable to connect the joysticks. But as these are homemade joysticks, they’ll need RJ45 sockets of their own into which one can plug the other end of… Read more »

DIY joystick for the BBC Micro – part 1

My recent PC build was undertaken partly to allow me to play Elite: Dangerous. There was no small amount of nostalgia involved in that decision: the original Elite was one of the few games I played back in the 8-bit days. But while I can now play the two incarnations of the game – separated by 30-odd years – side-by-side, there… Read more »

SmartParallel: refreshing the design

The SmartParallel, aka DottyMatrix, project has been languishing for a while now, but it’s time to get it restarted. SmartParallel is a serial-to-parallel interface that I embarked on because I wanted to be able to use my decades-old Epson MX-80 F/T III dot matrix printer with a number of platforms that don’t have parallel interfaces, such as the Raspberry Pi…. Read more »

Fixing an e-bike pedal sensor – part 2

Well, it looks as though this series of posts (of which this is the second and possibly last) could be badly mis-titled. For a start, it doesn’t look as though the pedal sensor of my malfunctioning e-bike is faulty. And it now appears unlikely that I’m going to fix anything – not in the near future, anyway. However, I had… Read more »

Fixing an e-bike pedal sensor – part 1

For the past four years one of my great joys has been cycling. Although of a certain age, and with not a few health issues, the advent of the e-bike has allowed me to return to one of the pleasures of my youth, as I’ve been known to blog about elsewhere. But we’re not here to talk about cycling –… Read more »

Building a PC: GPU – PNY GeForce GTX 1660 Ti

First steps The case – Corsair Carbide SPEC-06 PSU – EVGA 1000GQ Gold The motherboard – Asus Prime X470-Pro RAM – Corsair Vengeance RGB GPU – PNY GeForce GTX 1660 Ti Putting it all together Wrapping up Elsewhere in this build I’d start by considering a modest component and upsell myself before actually clicking the buy button. The reason is… Read more »