Ben Heck’s DIY graphing calculator

Ben Heck’s got another terrific build: a DIY graphing calculator built with a Raspberry Pi Compute Module (and later an A+).

No schematics yet, but if Ben does release them we’ll add a link here. Frankly, this is one of those projects that’s just so daft and so much fun to watch coming together (especially when things go wrong), that we suspect you won’t really mind that you can’t duplicate it at home (yet)…we hope you’ll feel the same.



Nuex* Luke Castle avatar


Banana avatar

He ends up using a model A+ not a compute module.

Liz Upton avatar

I know; forgot to mention it. Helen just mailed to remind me to update it too – you’ll notice it’s changed now!

Joe avatar

Did anyone else notice the little caption for this blog post on the home page? It reads “5318008.” Put that in a calculator and turn it upside down, and you see a hidden message! XD

Markus Schopfer avatar

That’s a really nice project.
Such a Pi-calculator could put the potential of Mathematica in the palm of your hand!

Federico Ramos avatar

This demostrates that the compute module is a hard nut to crack, it’s a neat piece of hardware but the design phase can be a challenge, I really to want play with this module :D

nelson avatar

From the clip it appears that he had the footprint for the screen socket wrong, it had solder mask over the pads, he should have notice it while looking at the gerbers, before ordering the PCBs.
Such things happen, specially in rushed projects, Murphy’s law and all.
This is not a compute module problem, and would be easy to fix, but it would require them to wait for new boards to arrive.

Blah avatar

Get this puppy on kickstarter, who wouldn’t want a truly programmable calculator?

Siddartha avatar

That’s the best invention and a nice project. Hopes this calculator will solve many problems for a mathematician. Thanks a lot for this precious gift to us..

Sheroy avatar

It should be interfaced with the wolfram language!! It will be one of the best calculators.

Some work on the input style may be required.

Crumble avatar


I needed theses days a calculator and thought to build me one with a Pi2 and Mathematica. But I needed one to solve my problems and not to generate more work. So I ordered me one, which shall be delivered today.

A mathematica device with a pocket caculator HCI will be nice. If you can sell it as a kit, wolfram may earn a few Euros and may allow commercial usage as well.

Eric Olson avatar

In the United States children are not allowed to use devices that have certain functionality on the SAT college entrance exam. From

the list of unacceptable calculators reads

Laptops or other computers, tablets, cell phones, or smartphones

Models that can access the Internet, have wireless, Bluetooth, cellular, audio/video recording and playing, camera, or any other smart phone type feature

Models that have typewriter-like keypad, pen-input, or stylus

Models that use electrical outlets, make noise, or have a paper tape

Calculator function on a mobile phone

In addition, the use of hardware peripherals such as a stylus with an approved calculator is not permitted. Some models with touch-screen capability are not permitted (e.g., Casio ClassPad). Check the list of acceptable calculators for models that are permitted.

I wonder whether a homemade calculator like the one Ben made would be allowed?

Crumble avatar

No. They need to be certified. Even if someone is willing to pay for this, there will be no solution that prevents the pupils to use a different software on it. So I would not certify such a device.

But there not only students need a good calculator. My new HP Prime seems to be really good compared to what I was used to in the 80s/90s. But you run into all the modern problems.
– The software has a lot of bugs.
– The certified keyboard layout is a pain in the ass
– A chatty imperative language on a calculator?
If they would have implemented a simple functional language like Miranda mixed with their good formula rendering system, used a better display, allowed external keyboards and this device is AWESOME for workplaces where you are not allowed to install the software you need.

A modular system which is not restricted by the learning market will be really nice. Based on the SoC of the Pi2 will it be the most powerfull system on the market. We need a calculator combat for students like all these robotic events ;-)

Gide avatar

Much work done in this (abandoned) project :

evil twin avatar

I wonder if that kind of keyboard (connected to the GPIO instead of standard USB) can be made to work in BBC Basic / RiscOS?

Liz Upton avatar

No reason why not.

compsystems avatar

Very useful project, but without a ti (tiemu), hp-emulator or xCAS port =(
The idea is to continue this user-calc, install a numerical and symbolic engine, or at least one hp-ti emulator

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