Tools that talk: adaptive technologies for the visually impaired

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Above: Hobart designer maker Duncan Meerding in his workshop.

Words and photos: Duncan Meerding

For the last 14 years I have been operating as a designer maker of lighting and furniture in Hobart, Tasmania. I have less than 5% vision concentrated around the periphery, meaning I am legally blind. This does create a range of challenges as a practitioner and means I often do things in a different way utilising more jigs or other pieces of assistive technology.

This article will discuss a few ways I set things up for some more basic operations and also look how my tablesaw and thickness planer now have a ‘talking’ digital read out system.

First things first

To start with, the key thing I do when I approach a machine is to make sure it is isolated from the power and use an off-cut or push stick to make sure it’s not in motion. I then cross-check the stop is on, or the tool is unplugged from the wall for smaller hand held tools. Once I have confirmed that the machine is in this stage I set up ready for the cut. For simple things like cutting up panels or drawers I use a range of talking or tactile tools.


Left to right: Talking tape measures are good but not as accurate as click rules; using a depth stop to measure in 10mm increments on the tablesaw which has a digital read-out and mini computer fitted to it; the click rule in action.

The click rule

For fitting shelves or drawer runners I would often use a talking tape measure. This is only accurate to 1 to 2mm tolerance so for greater accuracy I would cut oversize and reduce the size of stock incrementally by ‘kissing’ the blade. This is what I did for many years, as the talking calipers I have are a bit limiting due to size.

In steps a device I discovered a few years ago via Woodworking for the Blind. The click rule is great for transcription measuring. The main clicking part looks like a piece of threaded rod with a flat surface ground onto it which then inserts into a tubular piece of aluminium. A bolt for lock-off goes through the rod and intersects with the threads, and this is what creates the sound and feel of the clicking.

Each click represents a 1mm increment, with an extra tactile marker every 10mm. The device then has a range of add-on rods allowing for extension of up to one metre. This device is quite handy for fitting shelves or runners as you can do point-to-point transcription measuring.

For depth stops and for spacers I still often use tactile measuring blocks as they are extremely accurate for things like rebates. These tactile solutions are super helpful, but still have the limitation that the machine has to be static and isolated every time you want to adjust it.


Left to right: The author’s Wadkin thicknesser is fitted with a talking digital read-out; close up to the digital readout fitted to the SCM tablesaw; teamed with a mini computer, the Pro Scale Digital gauge reads out audibly on both sides of the tablesaw.

Talking machines

Most people reading this article would be familiar with the range of gauges available on thickness planers, from the traditional arrow on ruler version up to the digital read-out systems. One of my chief frustrations was the lack of off the shelf options for people who can’t read sight specific read-outs.

In my search for linear optical gauges I eventually found a company in the USA that understood what I wanted to do. Now I have Pro Scale Digital read-outs with a mini computer reading out audibly on both sides of my SCM tablesaw and on my Wadkin thickness planer.

How they work

Accurate Technology Inc had developed a system which got the proprietary signal out of the data output and converted it into a traditional USB (like a keyboard) signal. This converter meant the signal could then be plugged into a traditional laptop.
Whilst this is great as my laptop has text to speech talking and I could access the information, I was not 100% keen to have my laptop sitting on top of my thickness planer or tablesaw. I therefore discussed getting a purpose built mini computer (raspberry pie) programmed and custom built with a local programmer. These boxes were created to be robust enough to withstand the occasional knock and secured well enough to the machines so they wouldn’t rattle off. The box gets the USB signal and anytime I hit data send I now get the audible interpretation.

It took a bit of setting up with a local fellow furniture maker Stuart Houghton assisting with fitting things to be super robust, but now I have digital accessible information. This means I can adjust stops accurately on my saw without having to turn off the machine every time and I do not have to guess and check as I place things through the thickness planer.

For me and others like me, it’s exciting to see where these developing technologies can take us.

Duncan Meerding has been running his own designer maker practice for the last 10 years. He was a guest teaching fellow at the world-first Architecture Beyond Sight course at the University College of London in 2019. He is currently collaborating with Visibility in setting up a woodworking course for the blind in Tasmania for later this year. See his work at

Accurate Technology Inc,
Tape King – Talking Tape Measure from Caretec,
Click rule from


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