Demonstration Video and Circuit Diagram

I tried looking at what the issue with the LCD was, but unfortunately did not find a solution. Instead of recording my synthesizer in its current state, I recorded a demonstration prior to when I began soldering  – as a precautionary measure. Here’s the video.

Also, here is a circuit diagram demonstrating the connections of the components in my synthesizer.



Soldered board!

I moved forward and soldered my board today. Prior to doing so, I decided to record a demonstration of my synthesizer in use, in case there would be errors during the soldering process. Sure enough, it turned out my decision was the right call to make, as after I soldered all of the components onto my proto-perfboard, the LCD screen stopped outputting text.

I tried looking at the pins underneath the board, and soldered a bit more to make sure the pins were correctly connected. Initially, the issue was that the pins were not properly soldered onto the board, and therefore did not light up the LED backlight for the LCD screen. After that I managed to get everything up-and-running, but for some reason the text for the menus and items would no longer be displayed. I will try soldering a bit more tomorrow, to see if I may possibly fix it.

Fortunately, the synthesizer itself still works so I will still be able to demonstrate a working, audible product in the class.

Fluctuating Frequency!

I added a new feature to the synth, which allows the user to switch between having the frequencies of their oscillators fluctuate or not. If the setting is on, and the user then moves onto their oscillators, the outputted frequency for that selected oscillator will then be a random number between 0 and the value currently detected by the potentiometer; the potentiometer’s value then acts as a cap for the fluctuating frequency range.

New ‘Fluct-Freq’ menu item being displayed on the LCD screen

Here’s a clip of the new feature in action! The audio in the clip transitions from the two oscillators outputting sound at a constant frequency, so being randomized after the ‘Fluct-Freq’ option is turned on.

Menu display – continued

I programmed the appropriate text to be displayed for my current set of menus and settings, and it doesn’t seem to affect any of the outputted audio’s performance. One key issue is that when using a fast input speed for the lcd text, the lcd.clear() method takes a long period of time before it is able to print new text, and therefore starts printing garbled up characters. Due to this, I had to delay the speed at which it prints to 750 milliseconds, as of now.

This provides relatively slow feedback for the user, but it still manages to display information, at the least.

Menu display

I wanted to use the LCD that comes with the Arduino kit in order to improve user navigation, and possibly provide a more ‘premium’ feel. Although the LCD boots up and is generally connected in  the right spots, I’ve been having some performance issues.

If the LCD prints too much information at a rapid speed, such as in the ‘loop’ method, it severely distorts the main audio. As cool as it may sound,  I need to find a workaround. I really hope it can be accomplished.

LCD displays ‘Oscil One’ when the device first boots up




Some new features!

At this stage of the development, I’ve added two additional features to the synthesizer; an LFO and Low Pass Filter (LPF). The user interface is the same as my previous blog post, and the use would simply need to press the first button button to navigate through the different ‘main menu’ settings. The structure of the menu would be as follows:

Oscillator One -> Oscillator Two -> LFO -> Low Pass Filter

The arrows indicate which menu item the arduino would select, based upon the input of the first button. Here’s a video demonstration. One thing to be noted is that the LPF, once activated, only affects the cutoff frequency. For some reason, the resonance cannot be adjusted in realtime, but only when the program is first set up. I’ll see if I can possibly find a workaround.

Two Oscillators – Three waveforms

As the title suggests, my synthesizer can now switch between two different oscillators and and pick between 3 waveforms, for each. There’s also a potentiometer that lets the user adjust the frequency of the currently-selected oscillator .


The cable management isn’t top-tier, but I’ll (hopefully) figure out something very soon.