Get hands-on with number systems and explore the computer byte. Toggle eight bits and see their decimal, hexadecimal and octal value. Annotations at bit-level break down the displayed value and make comprehension easy. Powered by USB-C or a 9-volt battery.

Includes a built-in game: beat the high score by toggling in the correct bits for each number system. A great science, technology, engineering, and mathematics (STEM) learning kit.

It has been on display at Teardown 2026 in Portland and it will be in a US retro computing magazine this month!

for Retro Hobbyists

Altair-like input switches take you down memory lane. Select Octal mode, play the game and guess the bits. Recall how machines from the seventies did it. Want more? Explore the full 8-bit Workbench™ platform with clocks, byte full adders, hex keyboards and breadboards.

for Programmers

Have it sitting around on your desk. Especially handy with the low-level work. What is the hex value of these bits? How many will fit in a nibble? Why is this backwards relative jump in assembly going wrong, have I miscounted?

in the Classroom

Enables focused learning by doing, on a dedicated device. A great STEM-kit, in the field of computer science, electronics or mathematics. Sample lessons are provided. A game is there for students that need the extra motivation.

The kit is an easy solder exercise with no tiny parts. Launch a course quickly by ordering a pre-assembled batch. Contact us for the possibilities.

Demonstration

Functionality

The mode button selects one of the three number systems (decimal, hexadecimal or octal) to be displayed by the three digits. Hold the button to turn the digits ON or OFF. Handy for training purposes. The active mode is indicated by a green SMD LED. Please note that the three digits look a little faint on the pictures, this is because of the photography, they are clear and strong in real life.

With a built-in game. The objective is to toggle in the bit-value of the random number that is displayed by the digits. Be quick and score higher! The game can be played in each of the three modes. It keeps a separate high score for each mode.

The board operates at 5V, directly from USB-C or powered from a battery source. An input voltage of 6.5V to 12V is supported and is further regulated on the board. This means a 9-volt block battery can be used or two 18650 Li-Ion batteries. The kit comes with a 9-volt battery clip. It can be stowed away nicely at the back using an integrated cable reel.

Open Source

At the core of the board there is a microcontroller, the little black rectangle with 28 shiny legs. This little computer runs at 4 MHz and has a small memory of around 2 KB. It comes pre-programmed to let the board operate as it is intended to.

For advanced use it can be reprogrammed using the ICSP header connector. It can be flashed by USB using a PICKit 3 programmer for example. Make sure to break the two solder jumpers (JP4 & JP5) before doing so.

The firmware source v1.0 for the PIC16F570 microcontroller has been released under the the GNU General Public License version 3. It is available as a zip file containing the MPLAB X IDE project, which contains the C-code and .hex binary.

This way you can create your own games (maybe Snake?), display other/custom number systems or create something else like an interactive periodic table.

What's in the box?

The easy to solder kit includes:

• Bill of Materials (BoM)
• Schematics
• Assembly Manual, guides you trough the process of building the unit in 12 easy to follow steps
• Operation Manual, contains 8 lessons that teach about number systems and give some history of computing, printed as a 16-page booklet in full-color.
• Pre-assembled main PCB with all tiny parts, e.g. the USB-C connector and SMD parts
• Front panel PCB that holds the toggle switches
• Microcontroller, flashed to the latest firmware
• All parts that have to be soldered, like the LEDs, switches, digits and a 9-volt clip

All documentation is provided hard copy. Batteries are not included. The fully assembled version does not include the Assembly Manual. The project is on Hackaday.io as well.

Easy to solder kit

Contact us

Just send us a message if you have any questions, we are human. Determining worldwide shipping costs can be cumbersome, we are always happy to double check, just send us a request to do so for your country. Contact us if you need a classroom-batch, to quickly launch a course or when you just don't want to solder it yourself.

• Shipping is tracked (you receive the tracking number), unless impossible to your country.
• For USA: package can be tracked with USPS as soon as it is in your country. USA shipping rates include all import duties, which are paid by me (the seller).
• No insurance, my experience is this is a farce anyway.
• Item ships within 3 business days (unless the item is a pre-order campaign, check its duration and lead time).
• Delivery is usually done within 10-15 business days, but may rarely take 4 weeks.