Celari & Saira | Character dialogue

Celari

Hey Saira, I was tinkering with the idea of converting a heartbeat into a living soundscape. What do you think about building a little prototype that turns your pulse into ambient music?

Saira

Sounds like a neat feedback loop. The pulse is a natural metronome, so if we sample it with a piezo and feed the signal to a microcontroller we can map amplitude to filter cut‑off and generate a soft sine wave. I’ll need a good low‑pass on the sensor, an ADC with at least 12‑bit depth, and a DAC to drive the speaker. Just remember to keep the bandwidth wide enough to capture the subtle variations in rhythm; the human body is an irregular machine and we’re trying to make it more coherent. I’ll sketch a quick schematic in my archive, but I keep most of my failed prototypes in the basement – they’re the best teachers. Ready to start building?

Celari

Sounds great, let’s set up the piezo and pull in that pulse. I’m curious to hear how the heartbeat shapes the sound. Let’s start with the low‑pass and ADC, and then we can map the amplitude to the filter cut‑off. I’ll bring my prototype sketches, and we’ll tweak it in real time. Ready when you are.

Saira

Great, let’s fire up the piezo, grab the ADC, and run a quick low‑pass first. Keep the cutoff high enough to let the pulse through but low enough to smooth the jitter – think 10‑20 Hz is a good start. Once the raw signal’s in, we can feed the amplitude into a VCA that drives the resonant filter on the synth. I’ll set up the sketch on my bench, so you can tweak the filter in real time while we listen to the heart’s rhythm become music. Bring the sketches, and let’s iterate. This will be a good learning cycle.

Celari

Sounds like a plan – I’ll pull up my sketches and set my heart rate monitor ready. Let’s tune that low‑pass together and hear the pulse become a subtle groove. I’m excited to tweak the filter and see how the rhythm transforms. Bring it on!

Saira

Let’s start with a 5‑pole Butterworth low‑pass at 15 Hz, set on the Arduino’s analog input. As soon as the piezo picks up the pulse, we’ll feed the signal into the ADC, then normalize it and use it to drive the filter cutoff. I’ll run a quick test signal so we can hear the groove before you tweak the envelope. Bring the sketches, and let’s make the heartbeat a living metronome.

Celari

That sounds perfect, I’ll load my sketches now. I’m already hearing a little pulse in my mind – let’s see how it turns into a groove. Ready to tweak the envelope when you hit that test signal. This is going to be a cool little living metronome.

Saira

Load the sketches, fire up the piezo, and let’s monitor the ADC readout. Once you see the pulse wave on the screen, hit the test signal – I’ll trigger the filter with the amplitude envelope. We’ll keep the attack sharp, decay slow, so the groove lingers. If the envelope feels too flat, just tweak the multiplier on the VCA. Ready to hear the heartbeat shape a living metronome.

Celari

I’ve got the sketches running, piezo engaged, and the ADC output is showing the pulse. Let’s hit that test signal and tweak the VCA multiplier. I’m ready to listen to the heartbeat become our groove.We comply.I’ve got the sketches running, piezo engaged, and the ADC output is showing the pulse. Let’s hit that test signal and tweak the VCA multiplier. I’m ready to listen to the heartbeat become our groove.

Saira

Hit the test, and I’m setting the VCA multiplier to 1.2 now. Watch the waveform shift – the pulse should push the filter up, then settle. Ready when you are.

Celari

The test signal’s on, the waveform is shifting—watch the filter climb with each pulse, then settle. The multiplier is 1.2, so we’re getting a nice push. Let’s tune the attack and decay to let that groove linger. Here goes!