This is an unassembled kit of electronic components and circuit board. Soldering required. There is an assemble option at checkout if you want an assembled unit.

New May 2021 Now replaced with updated 2021 PCB design.

The circuit itself is the same as the 2020 version and they shared the same source code and firmware. The following improvements were made;

• Replace surface mount battery holder with through hole battery holder.
• Add spacing between the 3 LED modules.
• Now includes an IC socket in unassembled kit (although not recommended as it increase the units thickness).
• Reduce length of overall PCB layout.

These changes are added to address some feedbacks by previous kit owners and is intended to make the kit easier to build.

This is a new version of my same named calculator kit. Instead of employing the obsolete and expensive QDSP-6064 Bubble LED Module, this kit employ 3 x 3 digit common 2.5" high LED modules.

This is a microcode emulation, not a function emulation of the original calculators. Instead of implementing the very complex calculator logics. Emulation of the original TMS080x 4 bit MCU is implemented and have the calculator ROMs run against it. I believe the TI DataMath ROM was obtained from a TI patent document, while the Sinclair Scientific ROM was extracted by reverse engineering a 40+ year old chip via acid bath and microscope analysis.

The emulator was created to be;

• An easy-to-build beginner's soldering kit.
• A useful tool as a gift.
• A replica of antique electronic technology.
• Powered by a single CR2032 battery. Deep sleep / off mode consumes about 0.6uA power.

Emulation core is based on Ken Shirriff's work. This is not a new project. This project was done in June 2014. I am creating this page here to link this to a tindie project page and sell soldering kits I had created.

Hackaday project entry

Operation Instructions

• LPM4 (msp430 Low Power Mode) auto-off, can eliminate SPDT slide switch on pcb
• auto-off time is 60 seconds of in-activity. 'C' key to switch on
• move setup function from press-n-hold to 'C' + 5, 6, 7, 8, 9 keys
• setup is pressing 'C' and in very quick succession one of 6, 7, 8, 9 keys
• C+5 = button test ('C'+'C' to end test)
• C+6 = secret message edit (+ key to advance)
• C+7 = toggle datamath / sinclair roms
• C+8 = toggle slow / fast cpu
• C+9 = show secret message
• C+C = turn off (put to sleep)

Assembly / Soldering Instructions

I had taped one button as an example of how you should bend the pins w/ a pair of long nose pier and fit them in. you should solder them buttons on the top and you will have a smooth bottom. Tape down components can help with soldering.

Double check orientation of IC and battery holder before soldering. Consult product photo if in doubt.

Remove scratch protector from LEDs before fitting.

Cut out from colored plastic folders on top of the LED modules will enhance the contrast of the display.