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Fret Zealot, a Guitar Accessory with LEDs for Guitar Learning and Jams

Consumer electronics Education Embedded hardware development Entertainment

Learning to play the guitar is hard work. One US-based startup decided to change that. They created a full spectrum LED learning and display system called Fret Zealot. The Fret Zealot LED strip is attached to the neck of the guitar, turning it into a display.

Colorful flashing lights on the strip show where exactly to put your fingers. The device works together with a smartphone app where a beginner can choose various chord progressions they want to learn. More skilled musicians can also use Fret Zealot: they can pick songs in the app's library and arrange flashy jam shows for their friends.

A full spectrum LED learning system attaches to the neck of the guitar, turning it into a display and showing exactly where to put your fingers.


To launch the device to the market, the team at Fret Zealot needed to improve the hardware design of their existing product. They also needed to make it compatible with all mass-market full-size guitars, including bass guitars.


Integra Sources reviewed the existing solution for guitars with scale lengths of 24.75” (e.g. Gibson) and provided improvements to the circuit board. We also developed similar products for 25.5” (e.g. Fender) guitars and for bass guitars based on the initial circuit board design.

Components of the Fret Zealot learning device
Parts of Fret Zealot device

Scope of work

Technology consulting:

  • Reviewed current design
  • Optimized existing solution (we made it cheaper by getting rid of redundant components).
  • Validated suggested modifications.
  • Reworked the PCB design for the existing 24.75'' scale guitar model

Hardware development

We designed the hardware for both bass guitars and for 25.5'' scale guitars. Each Fret has its own microcontroller for controlling LED. The challenge was to meet the PCB size requirements so the board modifications would not affect the user experience. We needed to make sure all features were available on the flexible PCB.

  • Schematics design
  • PCB design
  • Generation files for manufacturer
  • Ordering PCBA
  • Hardware testing
  • Debugging

How it works

  1. Fret Zealot is stuck onto the guitar's neck under the strings.
  2. The device is synced with an app.
  3. The user picks the chord type in the app, and the chord and finger positions are displayed on their fretboard.

The functionality of Fret Zealot

  • Ergonomic design
  • Easy to install
  • Long battery life
  • Full spectrum LEDs
  • Phone and tablet support
  • MIDI file compatibility
  • Customizable light patterns

Technologies Used

  • EAGLE CAD IDE was used for Schematics and PCB design
  • Fret Zealot has many RGB LEDs, several ATTiny20 MCUs, and connector placed on the Flexible PCB


Fret Zealot is a long, thin vertical strip in the shape of an oversized comb. It can slip between the guitar's neck and strings without interfering with the user's ability to play. Fret Zealot lets you learn quickly and intuitively. After a user plays a note or a chord, the app detects the sound and the strip lights up showing them where to put their fingers next.

Fret Zealot had successful crowdfunding campaigns on Kickstarter and Indiegogo. They raised more than $300,000 and shipped 1,500 of the $200 devices with another 1,000 orders already placed.

Fret Zealot appearance

Pledged on Kickstarter

$ 300,000

Orders placed

1 000

Products shipped