Cryptoucan™ Manufacturing: Keypad Testing

Written by Lída Hrnčířová on August 8, 2019.

Have you ever wondered how does the testing process of Cryptoucan™ look like? Well, here’s your chance to see how we’re testing our keyboards. Today’s article includes recordings of the robot we built for this – that’s something you need to see!

We are carefully testing every part of Cryptoucan™ – software as well as hardware. Most of the firmware can be tested using usual methods of software engineering (CppUTest[1] for example).

But when it comes to hardware, everything gets a bit more complicated. We’ve already covered the testing process of Cryptoucan’s display in our previous blog posts Simple CV in Racket[2] and Cryptoucan™ Manufacturing: LEDs Revisited[3].

Another important feature to test is keyboard. Doing this manually is extremely labor intensive because there are many scenarios to cover.

Picture 1: Cryptoucan

So we built a robot to speed things up!

If you want to see the robot in action, click here.

The Robot

The most straightforward approach to emulating user input on keypad is to touch keys with a finger-like object. Keypad is capacitive, so we used a short steel rod with a bit of conductive foam on the tip as a “finger”.

“Finger” is mounted on a SCARA[4], which is assembled from 3D printed parts and some hobby servo motors controlled by Arduino. There’s a compensation for servo gear backlash in software, as our application does not need extreme precision.

Picture 2: The Robot

Picture 3: Raspberry Pi display

You can watch all the parts cooperating in this exclusive video!

Video 1: Cryptoucan™ Manufacturing: Keypad Testing


That’s all for this week, thank you very much for reading!


1. More info:
2. Read more in this article: Simple CV in Racket
3. Read more in this article: Cryptoucan™ Manufacturing: LEDs Revisited
4. Wikipedia contributors. (2019, July 3). SCARA. In Wikipedia, The Free Encyclopedia. Retrieved 15:56, August 7, 2019, from