Microcontrollers can be busy little beasts. That’s because we load them down with jobs to do – sometimes too many jobs. In the main loop of an Arduino, AVR or whatever microcontroller takes your fancy, we often spend time polling sensors and then throwing away the data as uninteresting. On the robots I’ve built in the past, for example, that polling… Read more »
The overall architecture of the Sheldon robot is going to be modular. Aside from a central computer (probably a Raspberry Pi or some such), there will be multiple computers or microcontrollers each managing some sub-system. And the first of these is for motion control. I decided on this hierarchical approach because of previous experience building robots. Most of these were… Read more »
The 9V motors on the T300 robot vehicle are each fitted with two hall effect sensors that act as encoders. I figured I’d take a closer look. The two sensors are positioned to read a magnet attached to the rear of the motor’s shaft. They are quite close together so that, as the magnet rotates, one will be triggered very… Read more »
The 9V geared motors fitted to the T300 tank, which forms the base vehicle for my Sheldon robot project, come fitted with encoders. I’m not sure I need these, but they might be useful to have. But first I had to do a little simple reverse engineering to work out how to connect them. Each motor has a six-pin connector,… Read more »
A comment over on Reddit made me realise that I haven’t yet mentioned a key characteristic of my Sheldon robot project – inaccuracy. I mean, I could* built a robot with incredible precision that would be able to locate and move itself to tolerances of fractions of a millimetre. Think of those amazing pick-and-place robots that populate circuit boards with hundreds… Read more »
Many beginners’ guides to electronics teach you how to build motor controllers using mosfets, H-bridge circuits and all that good stuff. And maybe I’ll get around to doing that one day. But to get this robot project up and rolling, I decided to go for an off-the-shelf motor controller. I’ve used many before, including Arduino shields from Adafruit and Snootlab…. Read more »
Right from the beginning I knew that the Sheldon robot would have a multi-processor architecture. This appeals to me the same way object-oriented programming appeals – you can create a modular system in which each part does a specific task and can be treated like a black box. The structure will be hierarchical. At the top – what I’m going… Read more »
One of the things that spurred my current interest in electronics was a resurgence of my fascination with robots. And so, here we go with another project – a robot base vehicle that I can use for experimenting with sensors and algorithms. (Technically, this is not a new project – it’s a new start to a years-old project, but anyhoo…)… Read more »
It’s always the same. “I’ll just hack out this quick program,” you think. And you get it to the point where it works and does the job you intended it to do. But then: “Maybe it would be nice if it also did this…” And even when you’ve added all the functionality the program will bear, and your wife is… Read more »
In the last post, I mentioned how I’m using a RetroClinic DataCentre to make it easy to transfer files between the BeebEm emulator on my PC and my real BBC Master 128. A USB memory stick plugged into the DataCentre becomes my main disk drive (*DRIVE 5) for program files. It also holds floppy disk images (single-sided .SSD and double-sided… Read more »
No, this isn’t going to be a tutorial on BBC Basic. Nor am I about to offer programming tips and tricks. This is about being comfortable while hacking. In the last post I wrote about recreating the first serious program I ever wrote on the BBC Micro. And I mentioned that I’d written the code using the BeebEm emulator running on… Read more »
So what was your first program? You know, the first one that meant anything. My guess is that when you unwrapped your first home computer (mine was a Sinclair Spectrum 48K) the lines of code you typed were little more than snippets – changing some colours on the display, perhaps, or making rude words scroll endlessly down the screen. You… Read more »
Ah, there’s nothing quite like the feel of a fresh, crisp OS install. It’s just that the OS I’ve just installed is Windows XP. Now that makes no sense… Or does it? As I’m now playing with my BBC Master again, I felt the need for a Windows machine to have alongside it. There’s a bunch of utilities that run… Read more »
Does anyone still use flowcharts for programming? What with today’s complex development frameworks it seems unlikely that anyone’s stopping to draw diagrams on paper. But maybe if they did we’d have fewer security vulnerabilities – just sayin’. My addiction to computers, in the early 1980s, was driven in part by ‘30 Hour Basic‘, an introduction not just to the language… Read more »
While idly mulling over how one might create a control panel for an eight-bit microcomputer – something I plan to do for my (very) slowly progressing Zolatron 64 project – it occurred to me that there might be occasions when it would be useful to send a brief pulse. I didn’t have a specific use case in mind. In fact,… Read more »