I was somewhat frustrated that I could not easily buy air filter foam inserts for the common 25cc Chinese chainsaw. Sellers sold the housing, but no filter element in it.
So, the project is to make a template to cut a foam element that is a neat fit inside the housing.
Above is a sketch laid up over a picture of the filter cover. The template is made a little larger than the aperture so that the foam filter element compresses a little to fit. Continue reading A template for an air filter foam element
Above is the HC-SR04 ultrasonic ranging sensor, it was purchased for around $6 from a local eBay seller and delivered within days. Note that there are somewhat similar looking things with a second board on the back and a different interface, the basic HC-SR04 as pictured suits this project.
Several of my projects use Bosch BME280 sensor chips for measuring temperature, pressure and humidity.
Some correspondents have expressed problems using BME280 modules that they bought online, and it is usually because they have been cheated by online sellers misrepresenting BMP280 as BME280.
My projects that include code to initialise and read BME280 humidity will fail on a BMP280… check to see if the humidity results returned look sane. A driver may read the ChipID and fault on the ID returned by a BMP280.
The Bosch chips are usually visually different, and most clones likewise.
BME280 – temperature pressure and humidity sensor.
The code developed for support of some ultrasonic sensors has been merged into the original tanklevel project at https://github.com/owenduffy/tanklevel. A lot of refactoring to provide to the change.
So far, support is provided for HC-SR04 (and things that emulate its PWM mode), MB1242 (and emulations like GY-US42v2).
This article describes a coil former made from 3mm cast acrylic, cut on a CNC router, part designed in Freecad. The project is really an exploration of manufacture of one on my CNC router.
Above is the HC-SR04 ultrasonic ranging sensor, it was purchased for around $6 from a local eBay seller and delivered within days. Note that there are somewhat similar looking things with a second board on the back and a different interface, the basic HC-SR04 as pictured suits this project.
A series of tests were conducted of range to a hard surface at a distance of about 250mm and calculated ‘tank’ level and temperature plotted over time. Temperature is measured on the prototype breadboard using a DS18B20, and calculation of distance is compensated for the variation in velocity of sound with temperature. Continue reading IoT water tank telemetry project – HC-SR04 – first trial