you know Power supply? like for USB 5VDC...
have a constant ( controlled ) Output Voltage.
But there are also "bench" "lab" power supply what have a adjustable Voltage
but for some usage you need a constant current 'CC' ( with a variable Voltage )
like LED driver and battery charger...
then it would ( automatically ) have a CV mode and a CC mode, depending on the load and CV, CC adjustments.
in that case that current could be also adjustable, like by a POTI
so here is what i want to try:
-1-
first i order one of that digital potentiometer ( never play with that )
X9C103S
usually come as 103 ( 10kΩ aka 100 step a 100Ω ) or 104 (100kΩ aka 100 step a 1000Ω )
has 3 output like a potentiometer
and GND VCC input
and 3 digital inputs for adjustment ( even remember for restart ?eeprom?)
from
datasheet
compared to a DAC it is slow, and has a bad resolution ( 100 steps )
but for many uController what NOT have a DAC, it can be a useful add on.
first need solder pins:
as i want use it on breadboard ( back, for the uPCU side )
and for cable-connectors ( front ) for the POTI pins
-2-
what i want to try is to connect that to a ESP32s3 or a PICO W
check on free digital pins first:
PICO W:
3V3
GP20 CS
GP19 INC
GP18 U/D
GND
what raises the critical question? will it work on
3v3
or must connect to USB
5V but operate via 3v3 micro-controller pins?
even see a
Arduino lib
install v 0.2.3 and try on example first:
for the big code project use my
V271 change to V280
and load to a old PICO W ( gets [192.168.1.215] ) also enable already 4Relay and ADS1115
! as it was never used with relay ( and eeprom function )
get lots of boot info about first time use eeprom...
AND sadly have the idea that logic Relay ON OFF is wrong ?? last time with ESP32S3 worked ok ?
need check on both boards again!
also now, after change see it works with RPI PICO W
but shows wrong in MQTT, sure must dig deeper later.
7.11. 2025
restart here after 6 month with lots going on
+ setup old PC with UBUNTU
+ build new PC LINUX UBUNTU 25.20 ( and try WIN 11 )
+ rebuild RPI4 with new OS Debian Trixie and transfer old projects and setup Mosquitto, Node-Red ( with database .. )
+ rebuild RPI3 same but for HIST TREND with DOCKER: INFLUXDB & GRAFANA
more later
KLL
-3-
now, if that works i want buy a little power supply DC/DC CV CC 5Amax ( want drive from 12V SW-PS or Battery )
it is ONLY buck , NOT buck boost
means its output voltage will be Vin -0.3 V, not higher.
datasheet
and ( keeping the CV adjustment on poti ) replace the CC poti with that digital poti
again raises a critical question? can the digital poti drive that PS and first
what are the voltage levels that poti is on.
so first need to remove the poti to external with 3 wires and start measuring to GND.
as the PICO will have its own isolated power-supply it could 'FLOAT'.
