The Return of PENDA — Version II is Here!

[DADD]

Hi everyone,

I’m excited to announce that PENDA II is now available on GitHub!

This new version is a significant evolution of the project and brings several major improvements:

• Full stereo processing
• Digital Dry/Wet control using digital potentiometers
  → The best of both worlds: a fully analog dry path, and the ability to store the dry/wet mix with each preset
• A redesigned power circuit focused on audio quality:
  • Effective filtering of noise from the power supply
  • Strict separation of analog and digital ground planes
  • Dedicated regulators for analog and digital sections

With PENDA II, we’re moving from a “design to cost” approach (PENDA 1) to a philosophy that aims for audio excellence and reliability — no compromises.

Naturally, PENDA II comes with its own dedicated software platform, designed to fully leverage the capabilities of the new hardware.

The project is available here:
Harware
Software

first PENDA post

Yet Another Pedal? Meet PENDA!

Hey everyone, I know, I know… another pedal project, right? But stick with me for a second because PENDA (Platform for Effects oN DAisy) brings a few cool twists to the table! What makes PENDA different? 100% Analog Dry Path: Yep, the dry signal stays fully analog to preserve your tone’s integrity while still offering powerful digital effects. Large 2-inch SPI Display: Bigger screen, more room to tweak and see what’s going on. Perfect for navigating complex settings or just showing o…

Feedback is welcome!
Philippe

[Takumi_Ogata]

Awesome!!
Great to see this project keep evolving. I would love to see videos of the pedal in action too when you get a chance

[keyth72]

@DADD I just got around to checking out the Penda2 files, and I’m very impressed! Everything about it looks super professional, including the schematic and layout. The fully analog dry path is a great addition, something I haven’t seen in other daisy seed boards. I’m surprised there hasn’t been too much traction in the community, but maybe a demo of it would help (to second what @Takumi_Ogata said). The CubeIDE based software framework is intimidating, coming from only using libdaisy, but that’s part of why I’m interested in your project. I tried out your CubeIDE template, and that worked right off the bat for blinking the LED. It would be really cool to get a better understanding of microcontroller programming with CubeIDE, and your code and references are very helpful in doing that. Thanks for making all of this open source and sharing your expertise!

Question - if I wanted to build a Penda2, are there existing BOM and pick and place files to go with it for having it assembled by JLCpcb? I saw someone else ask a similar question awhile back, did you hand solder your board?

Thanks!

[DADD]

Hi Keith,

First of all, thank you for your message and for the stars on GitHub.
I’ve checked out your projects, and it’s clear we share a lot of common interests. I also really appreciate the quality of your work.

For more ambitious projects, I personally find STM32CubeIDE to be the best development environment. The Eclipse IDE is ergonomic, powerful, and pleasant to use. STMicroelectronics tools are perfectly integrated, and debugging is a real pleasure. CubeMX makes it possible to configure almost every part of the microcontroller — clocks, SPI/I2C buses, SDRAM interface, GPIOs, USB, and more — without writing a single line of code.

The HAL libraries from ST are simple, well-documented, and all share a consistent structure. With a bit of practice, the learning curve is quite fast. These days, I actually struggle whenever I have to go back to Visual Studio Code!

As I mentioned in a previous post, I don’t have any experience with assembly subcontracting through JLCPCB or PCBWay. I usually solder all the SMD components by hand. The PCB is designed for that, with slightly enlarged footprints and components that aren’t too small or tightly packed.

I use a basic soldering station (<€60) with a fine-tip iron and a hot air gun (very useful for desoldering). I also have a basic digital microscope (<€100) to inspect solder joints. You’ll need fine tweezers, thin solder wire (~1 mm), flux, desoldering braid, and isopropyl alcohol for cleaning. With a bit of practice, hand-soldering SMDs is actually quite easy — and often faster — than working with through-hole components.

I don’t have a ready-made BOM, but it can be easily generated with KiCad. If you have any doubts about component selection, I can help — everything used is quite standard.

Regarding OSCAR II, I have a version 2 that I haven’t published yet, mainly due to the limited community interest. This version integrates the audio codec directly on the PCB, which allows for proper input/output filtering and better power supply control and filtering. It also upgrades to a 2.4-inch display.

I’m currently finalizing another pedal project, featuring both a software toolkit and a hardware platform built around an STM32H743. (It will be available on my GitHub soon.)

Best regards,
Philippe

[keyth72]

@DADD That is awesome! Can’t wait to check out the new project, that’s exactly what I want to learn how to do. I actually just finished a STM32 design tutorial (Phil’s Lab #65 on youtube) and have a simple stm32 design I was planning on getting manufactured to learn the basics. That board uses a stm32F103.

With the version 2 using a separate audio codec, you’re still using the daisy seed for the processor? Proper power and audio filtering is something that I’m interested in understanding better.

Getting boards assembled isn’t too difficult to set up, it just takes some time selecting the right parts. JLCpcb has their own parts inventory and website that makes it fairly easy, and if they don’t have something they can source it. PCBway doesn’t have their own parts library so they source all the parts based on the project, and they can do part selection for you. In my experience it takes longer for PCBway assembly, but I’ve had success with both places.

Which audio codec are you using? I did a little research into them and the Cirrus Logic ones looked really good. I think it was the CS4272