ACS758 Current Measurements

I’ve been designing a breakout board for the ACS758 hall-effect current sensor. The first few prototype boards came in and I decided to give them a quick test. The results were not quite as I expected so I thought I’d put write about them here, for others that might be using this IC. These current … more

Arduino and LED Matrix Display

I was asked to build a BIG LED display for a pedal powered cinema for a film group in Brussels (more about that in another post). I found these huge displays from Embedded Adventures and had wanted an excuse to have a play with one of them for a while. This is a post about … more

Arduino and Mobile Data

I’ve been wanting to play around with sending data via a mobile SIM card and, after needing to do it for another project, here is a short post on my attempts at getting it all going. I used an off the shelf GSM/GPRS module (the SIM900). I tried this using both the Arduino Uno and … more

8 x 32 LED display unit

I’ve been messing around with some 32 x 8 LED displays – as I have been wanting to create graphics. These LED displays are from Sure Electronics are available for around $13 and use the HT1632 LED driver IC, with an SPI-like control. I have previously used these displays for a couple of projects here … more

Minimus, Arduino IDE and USB

I have mentioned the Minimus AVR before on this blog. It is a very low-cost ATMEL micrcontroller board with a USB bootloader. This post describes using the device as a HID (Human Interface Device) such as a keyboard or mouse. A challenge was set by a friend to take serial commands and, depending upon the … more

Humidity sensors part II

Following on from my previous post on measuring humidity, I decided to test another couple of humidity sensors I had lying around. These were the DHT11 and the DYPTH01B. These are both low-cost capacitive sensors and both had been obtained when I put in an order with a Chinese supply website (Sun Tek Store). Neither … more

Humidity sensors

For a new project I am looking at measuring weather data in remote locations. This is for a low-cost, low-power wind data logging unit. The main parameter to record is, of course, the wind speed and I am doing this with ten minute averages from a pulse-output anemometer. While this data is useful, it would … more

Multiple Sheet Schematics in KiCAD

For PCB design I use the open-source schematic and PCB design software KiCAD. Its a great program and has gotten a lot better recently. It is unlimited in size, components and number of layers and has lots of the features of very expensive professional PCB layout software. There are times when having just one schematic … more

Surface Mount PCBs

Following on from the surface mount reflow oven I built, I thought I would report on its performance and my experiences with surface mount devices. I had designed a relatively complex board which had a number of devices which were only available in a surface mount package. So I decided to produce this board with … more

Battery Monitoring Circuits

Accurately monitoring lead-acid battery state-of-charge would help with the long-term sustainability of off-grid renewable energy systems. There are a number of ready-built products already available, mainly for the recreational vehicle market (eg. boats) and are relatively high cost (too high to include within a small off-grid power supply system). There are also a number of … more

Fast PWM on ATTiny85

This is a post about changing the PWM frequency of an ATTiny85 which has been programmed via the Arduino IDE. I wanted a faster PWM frequency to remove audible noise on a dump load controller I had been designing. This controls an output load using PWM and a FET. This produced audible noise when running. … more

TFT LCD display

This is a post about getting a graphical full colour LCD screen running with an Arduino. The sample screen was the ITDB02 1.8″SP unit from iTead Studios. It is based upon the ST7735 control IC which uses serial data for the display.   … more