17 Sep
2025
17 Sep
'25
3:31 p.m.
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 <paulkoning(a)comcast.net> wrote:
On Sep 17, 2025, at 3:57 PM, Adrian Godwin via
cctalk <
cctalk(a)classiccmp.org> 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