Talking Ruler (AKA RixTalk)

At a recent visit to the Google Accessibility Discovery Centre with colleagues from Rix Inclusive Research, amongst the many accessible items on display we saw a ruler that is available for people with sight impairments (they called it a ‘Braille Ruler’). The RNIB also sell an identical ruler to the one we saw at Google, but they call it a ‘tactile ruler’. Both have cutaways every 5mm to help you make measurements, and raised numbers and lines at intervals of 5mm. Here is the one from the Google Accessibility Centre:

Here is the same ruler from RNIB (looks 3D printed to me):

Not being content with a static ruler, I thought it might be interesting to enhance this a little and add some speech to the ruler. So I created an alternative version. The prototype below is the work in progress, which combines the tactile ruler with speech output using (for the prototype at least) an Arduino Uno, with an Adafruit MP3 player for the speech output:

The RixTalk Ruler has similar notches every 5mm, but larger notches every 10mm to help distinguish between them. The ruler is also only 15cm long, as it was easier to print the prototypes this way (having to produce many versions before I got the dimensions correct). Inside each ‘V’ slot is a contact wire, each of which connects to an analog port on an Arduino Uno. The contact wires are visible in the side view below:

The pencil (shown above) has a 3D printed cap that makes contact with the graphite core of the pencil, and is connected to the 5V port of the Arduino Uno. When a slot in the ruler is touched using the pencil, it makes contact with the Uno and speaks the measurement through the MP3 player and speaker. The prototype uses wires to the Arduino (just five of the thirty slots for testing purposes), which is a bit awkward, but necessary to test the idea out. However, it could be made into a single unit, battery operated with an integral speaker and bluetooth connection to the pencil. That will be the next development if we decide to continue with it.

Video of the prototype is below:

The next stage of development is to embed the electronics inside the ruler itself, with an integrated battery and speaker, and remove the need for wires by using a bluetooth connection to the pencil. We have also looked at the prospect of adding a thin base to the ruler so that in addition to having the slots at 5mm interval, you can also ruler straight lines. I’ll add an image of the new version as soon as it’s printed.