Monday, March 3, 2014

Demo of Cushions at TADQ

I have decided to visit TADQ with the latest prototype. I have demonstrated the ability to move objects using an object drawn in a MS Power Pont slide. The development officer, occupational therapist (OT) and two technicians were there during the demo.
They appreciated the flexibility with the cushions compared to the earlier prototypes which used lids. The OT stated that very low or no pressure switches are ideal for people disabilities with spastic limb movements. All of them said that placing cushions alongside the head of a person will be ideal as most of the people with motor disabilities still have voluntary movements of the head unlike limbs. Use of capacitive sensors can eliminate the issue of spreading of saliva or sweat as they work based on the proximity. A protective cover can be used to place the cushions inside. OT stated that this is a significant advantage as opposed in using Makey-Makey.

They mentioned that it would be great if the number of wires can be reduced further by having wireless connections between cushions and the controller. To do so it will be necessary to install some electronic gadgets inside the cushions which can result in a higher cost and an extensive design effort. While this kind of an effort is difficult, it will be feasible to hide the wires where they would not disturb the user.

We have discussed the possibility of having a switch that will turn on with a single touch and remains turned on until the next touch. This type of a switch will be useful to control objects in a game as people with weak hand movements may find it difficult to apply pressure on a button for a longer period.

They were extremely happy with this new prototype and said they will help me to trial this with some of their clients. It will be easier to reach people with disabilities with the collaboration of TADQ as they possess a very strong client base. Another successful visit! This time I decided to have a little nap on my way back to city in the train...

New Prototype - Cushions and Capacitive Sensors

It was time to move on from the first prototype that used metal lids and a hardboard. In this prototype cushions stitched with conductive fabric were used as the buttons. However, any conductive material can be used here instead of the fabric as the fabric can be costly. Instead of using Makey-Makey as in the previous prototype, Adafruit’s Bluefruit EZ-Key controller has been used to map inputs to keys in a typical computer keyboard.
Adafruit’s Bluefruit EZ-Key controller
Connectivity from EZ-Key to the computer is wireless (Bluetooth) unlike Makey-Makey which allows more flexibility. Two capacitive sensor modules have been deployed to receive inputs from cushions which then were transferred to EZ-Key. It is possible to emulate twelve (12) keys in the keyboard using this setup. My associate supervisor and one of the grad students helped to fix capacitive sensor modules, EZ-KEY and the batteries which power them in to a small plastic box.

Knbos to recieve capacitive inputs

Inside the plastic box
Wires with a pin on one end and a crocodile clip on the other were used to connect cushions with the capacitive sensor modules using knobs on top of the plastic box (see Figure 4). Unlike Makey-Makey, there is no requirement for the person to be grounded as a capacitive sensor can detect the proximity of a moving object and trigger a switch once it reaches a given range within the sensor. A simple GUI based software application is also available to customize key mappings of EZ-Key, if required.

Cushions with conductive fabric connected to the capacitive sensors

 Instructional video for the prototyope
Next step is to take this set-up to the people who I had discussions with and recieve their feedback. Fingers crossed for positive and constructive feedback...