This article is a desk study of the CirroMazzoni Baby loop.
Above, the Baby loop is a small transmitting loop with a novel remotely controlled loop tuning capacitor and tuning mechanism, and gamma match. Continue reading CirroMazzoni Baby small transmitting loop – a desk study
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
IoT water tank telemetry project – ultrasonic sensor – #1 described an inexpensive ultrasonic ranging sensor for trial.
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.
In this second trial, the battery saving feature has been activated. It powers the HC-SR04 on for each measurement, waiting 600ms for the HC-SR04 to stabilise. Continue reading IoT water tank telemetry project – HC-SR04 – second trial
A recent video explained how to use a Smith chart to solve a series single stub match using coax.
The diagram above from the video shows the topology of the series stub match. Continue reading Pitfalls of series stub matching with coax
IoT water tank telemetry project – HC-SR04 – first trial mentioned an inexpensive ultrasonic ranging sensor for trial.
Above is the JSN-SR04T-3.0, a waterproof transducer on a cable and the electronics board. The protocol is HC-SR04 PWM. No specifications or datasheet were found (other than the seller’s brief description). Continue reading IoT water tank telemetry project – JSN-SR04T-3.0 – first trial
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.
Above, the BME280 is a small square package, about 2.5mm each side. Continue reading BME280 vs BMP280
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).
A work in progress…
IoT water tank telemetry project – ultrasonic sensor – #1 described an inexpensive ultrasonic ranging sensor for trial.
Above is the GY-US42v2 ultrasonic ranging sensor, it was purchased for around $14 on Aliexpress delivered within 10 days. Continue reading IoT water tank telemetry project – GY-US42v2 – first trial
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 a 3D view of the part design. Continue reading Coil former made of cast acrylic sheet
IoT water tank telemetry project – ultrasonic sensor – #1 described an inexpensive ultrasonic ranging sensor for trial.
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