Guitar Tuner for a Blind User – from Lush Projects

Many sighted guitar players may not realize that their favorite electronic tuners would not be much of help to them if they did not have LCD displays. There are a handful of guitar tuners that emit audible notes but they are usually not the “hottest” items on the market and are generally not produced by mainstream gadget makers. Well, apparently, you don’t have to be one to come up with a guitar tuner that works for those musicians who rely on ears rather than their eyes to tune their instruments. đŸ™‚

This was sent to me by a good friend of mine and was way to cool to pass.

This is a project I did for a colleague at work. It’s a modification of a Cherub Guitar Mate WST-550G guitar tuner to provide an audible output to an earpiece so a blind user can tune a guitar.
How it works

I chose to modify the Cherub tuner because it uses an LED display which I thought would be easier to hack-into than the LCDs used by many of the new tuners or the analog meters used by the older tuners.

Once I got the tuner I probed the LEDs and found that they had a common positive line and individual negative lines that were controlled by a dedicated chip in the tuner under the inevitable blob of plastic.

To make the modification I attached a second box to the back of the Cherub tuner. In this box is an AVR ATMEGA 168 which provides the audible output. A large hole was cut between the Cherub tuner and the new box and wires run from each of the LEDs to the AVR. I also moved the battery to the new box to create space to attach the boxes and run the wires.

As well as the two controls on the original tuner I also added a button which selects which string the user wants to tune. If the tuner is showing an output for a different string then no audio sound is produced. This prevents rather confusing sequences of sounds that occur if you don’t put this check in.

Read more of Guitar Tuner for the Blind from their website.

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