What kind of logic circuit do you see here? This logic circuit was optimised for symmetry and art. Can you see which function is implemented in this circuit? You find more about logic gates and how they work on this Wikipedia page. Check the hints below, if you get stuck. Additional Challenges The logic circuit…
Bottle Opener for Elderly People or with Disabilities
Older people often have troubles opening plastic bottles. Also, people with gout or other disabilities lack the required strength to turn the small caps independently. The reason is the small diameter of the caps, which requires a strong grip with just two fingers. There exist a variety of helper tools, assisting this task by increasing…
Filtered RPM Measurement Using PIO
The Raspberry Pi RP2040 chip is a remarkable microcontroller. The programmable IO block (PIO) is only one of many great features of this chip. In this post, I show you a method of how to utilise PIO, to capture the speed of an attached PC fan with included software filter. Most fans have a feedback…
Split Storage Boxes Update
I got many requests to add split storage boxes to my system. Reasons were to print huge boxes and printing boxes on small printer beds. In the past few days, I released an update to my storage boxes system, introducing the first split boxes. If you bought the storage boxes set from my shop, you…
How to Print the Turntable Platform
When I wrote part 3 of the pet feeder series, I did not expect the light transmission issues of this part. Now, I have two solutions with new revisions of the part. Solution 1: Epoxy Filled Slots This is the superior solution with the best results, but it requires you to fill four tiny slots…
Comparing Five Turntable Platform Revisions
To solve the problem with light inference, I tested five different revisions of the turntable platform. For each revision, I recorded the sensor values and compared them to find the best solution. Visual Comparison Revision A is the original with the light inference problem. In the text, I describe only the differences to this original…
Let’s Print a Cat/Pet Feeding Device (Part 7)
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,…
Adding a Light Barrier using Epoxy
As you read in my last post about the pet-feeding device project, there was an issue with the fill sensors. The lines from the 3d-print transferred the light directly to the sensor and made a useful measurement impossible. One of the solution to this problem is a small gap between the LED and the 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…
Project Update: New Stepper Motor Driver
In this short update, I will talk about the improved stepper driver for the pet-feeder device. While working on the sensor board, to see if the fill sensors work as expected, it also involved using the stepper motor. Here, I realised, the combination of stepper motor and driver I worked with is way too noisy…