Hackaday Prize Entry: $50 Foot Controlled Mouse

ALS robbed one of [C. Niggel]’s relative’s of the use of their upper body. This effectively imprisoned them in their house; ALS is bad stuff. Unfortunately too, the loss of upper body mobility meant that they couldn’t even use the computer to interact with people and the outside world. However, one day [C. Niggel] noted that the relative’s new electric wheelchair was foot controlled. Could this be adapted to a computer mouse?

He looked up commercial solutions and found them not only prohibitively expensive, but also fraught with proprietary drivers and all sorts of bad design nonsense. With all of the tools out there today there was no reason this couldn’t be quickly prototyped and sent to the relative in need.

He used a combination of conductive thread, neoprene, and velostat to build the pads themselves. The pads were balanced with some adjusting resistors in series. The signals are sent to an Adafruit Feather board which interprets them and converts it to a PS/2 standard.

The first version of the mouse used separate pads glued to a MDF board with contact cement. However this, along with some other initial design flaws, resulted in premature failure of the mouse. [C. Niggel] quickly returned to the lab and produced a new version with more robust construction and mailed it off. So far so good!

Hackaday Links: November 23, 2014

The 2015 Midwest RepRap Festival, a.k.a. the MRRF (pronounced murf) was just announced a few hours ago. It will be held in beautiful Goshen, Indiana. Yes, that’s in the middle of nowhere and you’ll learn to dodge Amish buggies when driving around Goshen, but surprisingly there were 1000 people when we attended last year. We’ll be there again.

A few activists in St. Petersburg flushed GPS trackers down the toilet. These trackers were equipped with radios that would send out their position, and surprise, surprise, they ended up in the ocean.

[Stacy] has been tinkering around with Unity2D and decided to make a DDR-style game. She needed a DDR mat, and force sensitive resistors are expensive. What did she end up using? Velostat, conductive thread, and alligator clips.

You know the Espruino, the little microcontroller board that’s basically JavaScript on a USB stick? Yeah, that’s cool. Now you can do remote access through a telnet server letting you write and debug code over the net.

The Open Source RC is a beautiful RC transmitter with buttons and switches everywhere, a real display, and force feedback sticks. It was a Hackaday Prize entry, and has had a few crowdfunding campaigns. Now its hit Indiegogo again.

Speaking of crowdfunding campaigns, The Mooltipass, the designed-on-Hackaday offline password keeper, only has a little less than two weeks until its crowdfunding campaign ends. [Mathieu] and the rest of the team are about two-thirds there, with a little more than half of the campaign already over.

Making flex sensors on the cheap

When [Michelle] was making a sign language translation glove, she needed a bunch of flex sensors. These flex sensors cost about $10 a pop, meaning her budget for the project was eaten up by these bendy potentiometers. Since then, [Michelle] figured out a great way to make extremely inexpensive bend sensors using anti-static bags and masking tape, allowing her to start her project once again.

The build works by sandwiching Velostat plastic bags – the same electrically conductive bags all your components arrive in – between layers of masking tape. A jumper wires is attached to a strip of Velostat attached to a piece of masking tape. Between two of these anti-static/masking tape assemblies, another piece of Velostat is placed. After laminating all these pieces together, [Michelle] had a primitive yet very functional flexible potentiometer.

After attaching one of these flex sensors to an analog input of her dev board of choice, she had a wonderful and inexpensive flexible sensor. You can check out this sensor in action after the break.

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