Sundial is a multi oscillator tremolo pedal. Traditional tremolo effects use one basic waveform to modulate the amplitude of an input signal. Sundial builds on this by adding another oscillator and additional waveshaping effects. Both oscillators have individual frequency and amplitude controls - this allows users to create interesting rhythms and blend the oscillators as they please.
Timeline
Breadboarding:
The initial idea was to use analog oscillators to control the voltage sent to a home made vactrol (made with an LED, LDR and some heatshrink tubing) in order to perform the amplitude modulation.
This was done with a pair of NE555 chips setup as square wave oscillators. While this functioned correctly, after testing I though it required more options and added complexity. The second iteration on the breadboard used two XR-2206 function generator ICs. This provided additional wave types (sine, square, triangle).
After testing the second iteration, I decided to move to a digital platform (The Daisy Seed). This would allow for integration of encoders rather than potentiometers, complex wave shaping functions and a more precise method of developing the signal processing.
PCBs:
PCB 1: This pedal has had two PCB iterations to date. The first (yellow) holds the original 555 based circuit. This was an important step in terms of interface design as it allowed me to construct a proof of concept pedal with a PCB and casing. Using the functioning pedal made me reflect on the interface and what I wished it did.
Resin 3D Print (Version 2):
Daisy Seed PCB (Version 2):
The second casing iteration went better than expected and worse than expected. The material qualities of resin printing are much more aligned with injection molding than traditional FDM printing. Almost invisible layer lines and 100% infill make the part look very professionally made.
Unfortunately, the clarity of the resin made visible some structural elements under each potentiometer. Additionally, I liked the resin print enough that I decided to forgo the planned wooden side panel - leaving random holes on each side wall.
Unfortunately, the clarity of the resin made visible some structural elements under each potentiometer. Additionally, I liked the resin print enough that I decided to forgo the planned wooden side panel - leaving random holes on each side wall.
PCB version two (blue) integrates some of the aforementioned interface decisions such as
a clearer/smoother casing, a momentary footswitch, and an improved parameter layout.
What’s Next?
I believe this project needs one more iteration of both the PCB and the casing designs. While PCB Version 2 improved upon it’s predecessor - it still needs some changes. Firstly, swapping the potentiometers for a group of rotary encoders and multiplexed RGB LEDs. I’m going to use rotary encoders which have a push button under the dial assembly - this feature can be utilised to switch between different parameters/modes (and having LED colour change to reflect this).
Secondly, each potentiometer will have eight LEDs forming a ring around it. This can be used to improve user feedback - showing each parameters value in a ‘progress bar’ style. This is part utility and part aesthetic, the function will improve usability - but an additional note I had on version one and two is that the casing did not glow enough and the added LEDs will help this.
Once I complete the third iteration - I will begin external user-testing to hopefully bring them to a high enough quality to sell.