Assume, while digging out an ancient site from 450 AD, you found a mysterious stone with a digital display. Your analysis finds five inputs for five segments (a–e) and six outputs (1–6). It seems to be a classic multiplexed display. What is this display for? What is the highest continuous sequence of numbers it can…
Logic Gates Puzzle 11
The shown logic circuit performs a well known function; can you discover what it is? The circuit was not optimised for functionality, but to create a symmetric artwork. If you need to know the meaning of the used logic gate symbols, have a look at this Wikipedia page. Also, there are great videos from Ben…
Logic Gates Puzzle 10
The shown logic circuit performs a handy function; can you discover what it is? The circuit was not optimised for functionality, but to create a nice artwork and interesting puzzle. If you need to know the meaning of the used logic gate symbols, have a look at this Wikipedia page. Also, there are great videos…
Logic Gates Puzzle 1
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,…