Lots of people know about curves of constant width – for example the UK 50p and 20p coins: despite their apparent non-roundness they have constant width when measured by parallel jawed calipers or the mechanisms inside vending machines. If the shapes of these coins are extruded as prisms they can be used as rollers for […]
Category archives: Programming
E-paper display module driven by Arduino
These E-paper displays work well and look nice. At the time of writing you can get the 1.54 – inch size (200 x 200 pixels) from Banggood, but there are other sizes in the same range and my code should work with the bigger ones too. I have one on order to test. Search on […]
Revisiting the MinAttak chess problem
I blogged about my old Java Applet for the chess minimum attack (dominance) puzzle previously here. But of course Java Applets are now deader than a very dead thing that’s also been poisoned, burnt, and crushed. I’ve been playing around trying to learn a bit more JavaScript, and as a learning exercise, I coded up […]
Decoding FrSKY telemetry data with an Arduino – Part two
In part one, we looked at the standard FrSky ‘D series’ data packets that provide voltage and RSSI information. In this part two post we’ll consider the data format used by standard FrSky telemetry add-ons and how to decode the data from those without using a Taranis transmitter or a commercial display unit. In part […]
An Arduino-based programmer for the AT89C2051 chip – part 2
Here’s the software necessary to work the programmer board: Arduino sketch (for Arduino Mega 2560) PC program Here’s a screenshot of the program in operation. It should all be fairly self-explanatory. Please send me a comment if you have any problems or questions.
An Arduino-based programmer for the AT89C2051 chip
The Atmel AT89C2051 is a low cost microcontroller in a 20-pin DIL package. It runs MCS-51 (commonly termed ‘8051’) code. It works from 2.7V to 6V at anything from 0 Hz up to 24 MHz. It has 2K bytes of Flash memory to hold the program and 128 bytes of RAM. It has 15 I/O […]
POV source code – part 3
If you’re trying to compile the source code with the Keil compiler, you’re probably getting error messages about ‘undefined identifier’ or similar. This is because the standard Keil reg52.h header file doesn’t define all the necessary identifiers for the STC89C5x chips. We need to define the special function register (sfr) P4 = 0xE8; so the […]
POV source code – part 1
These posts relate to the previous few concerning the Banggood kit: Cross LED Dot Matrix Display Circuit Board Rotating Electronic Kit It uses an STC89C52RC microcontroller which is a (fairly) modern Chinese version in the 8051 family. You can program it in assembler, but I chose to use the C language for this project. The […]
ISP programmer for the STC89C51 and STC89C52
I couldn’t find an ISP (programmer) for the STC89C52RC that worked with modern versions of Windows. I found several programmers that work with other chips in the STC range. I did find one that worked on Windows XP, and with some hacking got it to work with Windows 7; however I had no luck with […]
Fast, small, and simple Arduino SPI RAM chip routines.
The 8-pin chip, 23LC1024, is a good candidate for adding extra RAM to simple Arduinos such as the Uno, Nano, Mini. It provides 128K of RAM (the ATmega328 chip that these Arduinos use only has 2K of internal RAM). The chip works at 5V (anything from 2.5V to 5.5V) and uses SPI so it only […]