Ironpedal <a href="https://www.pcbway.com/"><img align="right" src="images/pcbway.png"></a>

Guitar pedal firmware for Daisy Seed+Terrarrium boards. This project is sponsored by <a href="https://www.pcbway.com/">PCBWay</a> which is a great place to create custom circuit boards or you can choose from one of the many featured designs that people create and share. They make it very easy to bring your ideas into reality, highly recommended!

Features

Small hardware accelerated OLED display that can be toggled off to reduce EMI when not in use
16 different effects
Save/load your effect settings to external flash via QSPI
Effects can be individually enabled/locked
Record and play back up to 5 minutes of audio via the Looper effect
20 different profiles that you can use to save your settings (number can be increased)
Moog Ladder input filter for tone control
12 selectable screen colors to match the color of your pedal

Building from source

Make sure you have the Arm GNU Toolchain and OpenOCD installed, as well as make. To build, run the following command in the main directory.

make clean && make -j && make program

Customizing

Text colors can be changed on the Misc effects screen and the number of profiles supported can be changed in src/config.h, this will require rebuilding from source.

Supported effects

| Effect | Switch position | Knob 1 | Knob 2 | Knob 3 | Knob 4 | Knob 5 | Knob 6 | | ---------- | --------------- | ---------- | --------- | --------- | --------- | --------- | ---------- | | Master | 0000 | | | Profile | LPF | Resonance | Volume | | Overdrive | 0001 | Blend | | Mode | | Drive | | | Chorus | 0010 | Delay | | Rate | Feedback | | Depth | | Compressor | 0011 | Threshold | | Ratio | Attack | | Release | | Reverb | 0100 | | Feedback | | | LPF | | | Resonator | 0101 | Decay | | Frequency | Stiffness | | Brightness | | Autowah | 0110 | | Blend | | Wah | | | | Tremolo | 0111 | Depth | | Frequency | | Shape | | | Looper | 1000 | | Mode | | | Volume | | | Decimator | 1001 | Downsample | | Mode | | Crush | | | Phaser | 1010 | Frequency | | Rate | Feedback | | Depth | | Delay | 1011 | | Delay | | | | | | Flanger | 1100 | Delay | | Rate | Feedback | | Depth | | Pitch | 1101 | | Semitones | | Rate | | Flutter | | Harmonizer | 1110 | Semitones | Rate | Flutter | Semitones | Rate | Flutter | | Misc | 1111 | | | | | Color | Metronome |

Effect chain order

| 1 | 2 | 3 | 4 | 5 | 6 | 7 | | ------------------- | ---------- | --------- | --------- | ------ | ------------------------ | ------ | | Pitch | Autowah | Overdrive | Chorus | Delay | Misc: Metronome | Looper | | Misc: Tuner | Decimator | Resonator | Tremolo | Reverb | Master: Volume | | | Harmonizer | Compressor | | Phaser | | | | | Master: Moog Filter | | | Flanger | | | |

Usage

| Operation | Instructions | | --------------------------------------- | ------------------------------------------------------------------ | | Turn the OLED display on/off | Single tap both foot switches | | Change the current effect screen | Move the toggle switches into their correct position | | Enabling & disabling the current effect | Single tap the left foot switch (has no effect on Master and Misc) | | Locking & unlocking the current effect | Single tap the right foot switch | | Load saved effect settings | Hold the left foot switch for 3 seconds | | Save effect settings | Hold the right foot switch for 3 seconds |

My settings, feel free to use these as a starting point

| Effect | Switch position | Knob 1 | Knob 2 | Knob 3 | Knob 4 | Knob 5 | Knob 6 | | ---------- | --------------- | --------- | -------- | ------------ | --------- | ------------- | ------ | | Master | 0000 | | | 1 | 4.5 kHz | 45 | 150 | | Overdrive | 0001 | 45 | | Hard | | 45 | | | Chorus | 0010 | 75 | | 0.30 | 20 | | 90 | | Compressor | 0011 | -12 dB | | 2:1 | 0.118 | | 0.118 | | Reverb | 0100 | | 25 | | | 4.5 kHz | | | Resonator | 0101 | 20 | | 78 Hz (Eb2) | 25 | | 35 | | Autowah | 0110 | | 50 | | 10 | | | | Tremolo | 0111 | 50 | | 622 Hz (Eb5) | | Triangle Wave | | | Looper | 1000 | | Playback | | | 100 | | | Decimator | 1001 | 35 | | Soft | | 50 | | | Phaser | 1010 | 1.2 kHz | | 0.30 | 20 | | 90 | | Delay | 1011 | | 0 MS | | | | | | Flanger | 1100 | 75 | | 0.30 | 20 | | 90 | | Pitch | 1101 | | 0 | | 10 or 50 | | 10 | | Harmonizer | 1110 | +12 | 10 | 10 | -12 | 95 | 10 | | Misc | 1111 | | | | | 1 | Off |

You may find this chart useful when setting certain effect frequencies.

Keeping noise low

Digital noise is a part of digital pedals and Ironpedal is no different. In order to keep noise levels low, I recommend keeping the screen off when not in use if you decided to add one. These Chinese displays have pulsing voltage converters in them that produce a lot of noise when running and when they are refreshed.

I also recommend using an isolation transformer on the output jack and running separate ground wires wherever you can back to the power supply. The Terrarium is not the most efficient PCB and there are ground loops so we want to try to minimize those effects where possible.

Run the pedal from a dedicated power bank and not your computer as a lot of noise travels down the USB cable as well. If you opted to order a STLINK-V3MINI, I recommend adding another switch to be able to turn it off when not in use.

Build tutorial

Preparation

Print off the schematic with all scaling options turned off in your printer settings. This will make your life easier later and the last page is a physical template for drilling out the pedal case so this step is required.
Order all of the parts listed on page 2 of the schematic, I used Tayda Electronics for this.
Order a pedal case.
Order a 600:600 / 1:1 isolation transformer. This gets rid of digital noise on the output at the cost of some minor loss (a few dB when measured) on the low end frequencies. Noise is very noticable without one of these.
Order a Terrarium board from PedalPCB.
Order a Daisy Seed module from Electro-Smith with the headers attached, this is the heart of the pedal.
(Optional) If you want a screen, order a 1.5 inch 128x128 SSD1351 OLED display.
(Optional) If you want a very easy way of updating the firmware without having to open up the pedal every time to push the Seed BOOT/RESET combo, consider ordering a STLINK-V3MINI. Definitely worth it in my opinion to save your sanity.

Drilling out the pedal case

Cut out the pedal case template from the last page of the schematic and tape it in place. I used painter's tape for this but masking tape is also a good choice.

Pedal case template

Use a drill press if you have one but if not, hold the pedal case in a vise and try and keep your drill as straight as possible. Use a scrap piece of wood on the underside to keep your h

Ironpedal

Install / Use

README