Yes, I realised you suggested the Pico. Since the github code is aimed at linuxes I initially stayed with that, but the Pico is in the same class as the esp32 and likely could do it too. However, I don't know whether the github code uses any threads or other Unix features. It's less trivial to evaluate on linux than a no-OS platform. Might be worth looking at Zephyr.
On Wed, Sep 17, 2025 at 9:13 PM Paul Koning <[email protected]> wrote: > > > > On Sep 17, 2025, at 3:57 PM, Adrian Godwin via cctalk < > [email protected]> wrote: > > > > I presume Parallax stopped building the EMIC2 board through lack of > demand. > > The components seem to be still available and relatively cheap (about $12 > > on Mouser for each of the two large chips). The project page includes all > > the pcb details but I don't see source or even binary. > > > > A quick test of the github code uses about 8% CPU on a Pi 4 so should be > > within range of a Pi 0. The Pi 0 has no audio out and USB is probably > the > > cheapest way to do it. The built-in (PWM) audio on the Pi4 is dreadfully > > noisy so no real loss and alternative audio modules relatively expensive. > > You'd soon get to the $55 of the mikroe. > > > > Might be in range of an ESP32, though the big advantage of a Pi is the > > extraordinarily good range of support - all the facilities of Linux > without > > having to write even a monitor. > > Note that I said "Pico" which while also a Raspberry product has next to > nothing in common with a Pi, doesn't run Linux, and is far cheaper. > > Re audio: I think simple audio DACs are quite cheap, but they have odd > interface schemes (steady bit streams). No trouble at all for the PIO > engine in the Pico, though. I was thinking at one time about using one of > those when I needed a control voltage for a VCXO, but for that the PWM is > adequate. Direct PWM audio might also work ok with the PIO since it could > easily do 20 MHz clock rate so for, say, 11 kHz audio that's about 11 > significant bits. > > paul
