Homemade Flex Buttons

From Madwiki

I wanted to explore both voice and touch input to my spoken dialog system, Open Sesame, during field work in Tamil Nadu, India in 2006. Inspired by the success of the improvised and very affordable Phone-mic for voice input, I tried to create a transparent, replicable design for a touchscreen that you could build from recycled computer parts and other easy-to-find components. Touchscreens and touchscreen layovers are still fairly expensive, and keypad peripherals just can't do the job like flex buttons (like an ATM) so I tried to make my own.

I needed a firm material to house the buttons so they could be fixed firmly around a monitor. I made panels out of ABS plastic, which is durable and recyclable. My handy brother took the plastic up to work to cut to shape with a laser cutter. So things got fancy real quick, but we tried to keep the construction transparent so that it could be replicated with available materials in other environments. The friendly buttons were made from the bright orange rubber of gloves.

For each of the panels that would be fixed around a monitor (with velcro), three plates were needed. One with large holes for the orange rubber to show through. One with smaller holes which fit small plastic disks (yellow) which served as the buttons, and one with small squares to fit on/off switches. Two such switches can be stripped from all old CPUs - one is behind the "on" button, and one is behind the "reset." The switches were secured to the square cut-outs with epoxy.

Once the switches were secured, the bottom plate was flipped over and the yellow disks, also custom cut, were fit on top of the switches (you can see the small black rectangle). Bolts in the center and edges of the panel will hold the switches up off of the monitor.

Here, my handy brother is assembling four plates into a lasagna to make one of the four panels that will surround the monitor. The result is sturdy, pleasing to click, and can be fastened with velcro to a monitor. The wires from the switches for each panel are routed out one end of the panel to keep them manageable.

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These leads were each soldered to the function keys of an old keyboard that has metal, not plastic circuitry. The keyboard could still be used with any computer and it routes the flex buttons to the function keys which our program then responded to. The keyboard was bulky but sturdy and allowed us to explore flex buttons as an input option for users with little formal schooling who might want to access relevant digital materials without an intermediary to operate the machine.

One unexpected bonus of the handmade touchscreen was that it didn't shock you to use it, unlike touching the monitor directly, when the power supply was plugged directly into the current with no ground, which was sometimes the case during our field work.

In this picture, Brittoo of MSSRF is demonstrating both the voice (phone-mic) and touch (homemade touchscreen) input options of the spoken dialog system we created that delivers recommended agricultural practices via images and Tamil audio.

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