The seventh part of this series is all about the sensor board. It hosts the position sensor and four fill sensors. Speaking of sensors sounds complex, but these are just pairs of IR-LEDs and phototransistors. All design files for the board are in the GitHub repository and if you missed one of the previous parts,…
Tag: sensor
Unexpected Fill Sensor Problems
While testing the sensor panel, I ran into unexpected problems, requiring a small redesign. First, let me explain the simple working principle of the fill sensor circuit and what I tested so far. The Circuit The circuit for the fill sensors is straight forward. There are four input lines and one analogue output line. If…
Pet Feeder Update
A short update about the progress with the sensor panel and photos of the final input panel board. I assembled the new boards and are testing the sensors. As soon as all tests are done, and I am happy with the results and the board’s design, I will write the next part. These are 940nm…
“Read SGP30” Command-Line Tool
I published another small command-line tool for Raspberry-Pi. This time one to read data from the Sensirion SGP30 sensor. While you can communicate over I2C with sensors using Python, I found it not as reliable as using compiled C or C++ programs. To combine the two worlds, I started writing really small command-line tools, which…
“Read SHT31” Command-Line Tool
For various sensors, attached to Raspberry-Pi computers, I wrote small command-line tools to read the sensor values over the I2C connection. While you can do this with a Python script directly, I found using a compiled C or C++ program accessing the low-level device more reliable. The program I publish today, reads temperature and humidity…
Tiny Particle Sensor Node with Decorative Case
This article is about a small sensor node with a decorative case. It is based on the Raspberry Pi Zero W board with a custom sensor shield. I publish all hardware files for a simple sensor version, so you should be able to build this kind of sensor node and use it to monitor anything…
How to Design a Cheap Plant Watering Sensor (Part 6)
This is the sixth part of the meta-tutorial, where I talk about designing a cheap plant watering sensor. If you did not already read the first, second, third, fourth and fifth part please do it now. These parts contain a lot information which lead to this point of the tutorial. The fifth part ended with step 24, where I talked about calculating the total…
Plant Watering Sensor – Long Term Tests Take #2
I started a second take on the long term tests for the plant watering sensor. This tests are required to be sure, the measurements follow the expected cycles. After watering the sensor, the frequency should go down and while the soil is drying up, the frequency should go up the the initial value. Logging this…
How to Design a Cheap Plant Watering Sensor (Part 5)
This is the fifth part of the meta-tutorial, where I talk about designing a cheap plant watering sensor. If you did not already read the first, second, third and fourth part, please do it now. These parts contain a lot information which lead to this point of the tutorial. The fourth part ended with step 20, where I did usability tests and stability…
How to Design a Cheap Plant Watering Sensor (Part 3)
This is the third part of the meta-tutorial, where I talk about designing a cheap plant watering sensor. If you did not already read the first and second part, please do it now. These parts contain a lot information which lead to this point of the tutorial. The second part ended with step 14, designing a first prototype PCB. So…