Pushing Onwards

The Chipophone bleeps again! This is my cover of Pushing Onwards, from the 2010 retro-game VVVVVV.

I made the Chipophone back in 2010, and went on to release videos for about a year. But when the kids were born, I had much less time on my hands, and when I did get a few moments, I wanted to be as quiet as possible. But I kept reading all the comments and maintaining a list of requests.

As a bit of spare time came trickling back, I found myself focusing on other projects. It wasn't so much that the Chipophone was shelved, but rather that the Chipophone itself had become a shelf. That, and two of the switches had stopped working.

I was also getting annoyed by the aliasing that was prominent in high-pitched notes, especially when played with a vibrato. This had been pointed out to me from the start by several people, although it didn't bother me at the time. But once I started noticing it, there was no turning back. I knew how to fix it with a technique called PolyBLEPs, but that would have been too CPU-intensive for the sound-generating microcontroller, an ATmega88 that I had already pushed to the limit. So I decided to replace it with a full-fledged Raspberry Pi that I had lying around. This involved porting the C code and re-implementing the assembly code that I wrote all those years back, but luckily it turned out to be readable. I have configured the Raspberry Pi to boot a Linux kernel, but then to use my own program as init, which makes the system power up in a few seconds. It reverts to the normal init program if a jumper is present on a GPIO pin, which provides a neat way for me to access the system over ethernet and work on the software.

As for the switches, there's some kind of mechanical failure that I haven't been able to fix, although I haven't given up entirely yet. But my priority was to make the instrument playable, so I decided to replace the faulty switches with a pair of pushbuttons, at least for the time being. I moved the Fade Out and Record functions to these buttons. Especially for the Record button, this makes a lot of sense: It has three states now (stop, record, play) instead of the earlier two (play, record). In the old version, to stop a loop, I had to enter record mode and immediately leave it, thus creating a blank recording. But that always triggered an undesired metronome click.

So yeah, it took me a while, but it's great to finally have the Chipophone in good shape again. From my own perspective, it's just so much fun to play it! And hopefully it is still capable of spreading warm feelings of nostalgia and happiness around the world!

Download

• Linus Akesson - Chipophone - Pushing Onwards.mp3 (MP3, 2.8 MB)