Month: August 2022

Raspberry Pi Max current with GPIO for LED

Note: withdrawing more current(~15mA) from GPIO can affect the Rpi
https://raspberrypi.stackexchange.com/questions/9298/what-is-the-maximum-current-the-gpio-pins-can-output

  • Use 5V Pin (2,4)
  • Use GPIO as Negative volt
  • Max current withdrawn was 23mA for my use case
import RPi.GPIO as GPIO
from time import sleep 
import sys

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(21, GPIO.OUT, initial=GPIO.HIGH)

if sys.argv[1] == "on":
    GPIO.output(21, GPIO.LOW)
    #print("on")
    exit()

Fore More brightness:

  • Add multiple GPIO as GROUND
  • After adding GPIO20 as ground it was taking ~18mA from GPIO20
  • And Overall of ~36mA from both GPIO 20 and 21

Push multi-arch docker image

#ARM64
arm64_image_digest=$(docker manifest inspect nginx | jq '.manifests[] | select(.platform.architecture == "arm64")' | jq '.digest'| sed 's/"//g')

#AMD64
amd64_image_digest=$(docker manifest inspect nginx | jq '.manifests[] | select(.platform.architecture == "arm64")' | jq '.digest'| sed 's/"//g')


docker tag nginx your-username/nginx:amd64
docker tag nginx your-username/nginx:arm64

docker push your-username/nginx:amd64
docker push your-username/nginx:arm64


docker manifest create \
your-username/nginx:latest \
--amend your-username/nginx:amd64 \
--amend your-username/nginx:arm64

docker manifest push your-username/nginx:latest

https://www.docker.com/blog/multi-arch-build-and-images-the-simple-way/

export DOCKER_BUILDKIT=1

docker buildx create --use

docker buildx build --push --platform linux/arm64,linux/amd64 -t httpd-custom .

docker buildx stop
docker buildx rm

##10 0.064 .buildkit_qemu_emulator: /bin/sh: Invalid ELF image for this architecture

docker run --rm --privileged multiarch/qemu-user-static:register --reset

docker run --rm --privileged multiarch/qemu-user-static --reset -p yes



docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
docker buildx rm builder
docker buildx create --name builder --driver docker-container --use
docker buildx inspect --bootstrap

https://stackoverflow.com/questions/60080264/docker-cannot-build-multi-platform-images-with-docker-buildx

set and unset in debug bash script

set-x = print actual shell command

set -f = disable filename expansion [ ls *.yml ]

errexit = fails all script if any exit code arrives

pipefail = Failes multi Pipe statement if any false statement 

set -x -f -o errexit -o pipefail
set +x +f +e

https://stackoverflow.com/questions/68465355/what-is-the-meaning-of-set-o-pipefail-in-bash-script

What Does Bash “set -x” do?

https://www.newline.co/courses/newline-guide-to-bash-scripting/errexit

https://unix.stackexchange.com/questions/333867/what-does-set-f-in-korn-shell-do

ESP32 wroom 32 – MicroController

  • Fedora ardino IDE issue – https://github.com/arduino/Arduino/issues/11150
  • https://forum.arduino.cc/t/esp32-ide-compiler-importerror-no-module-named-serial/968605/10

sudo pip install pyserial

  • Open Arduino using Sudo
  • Stable repo link for Esp32
https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
  • File > Preference > Additional Board Manager
  • Tools > Board > Board manager > esp32 > Install

  • Tools > Board > ESP32 > ESP32 Dev(or any board that you have)
  • File > Example > WIFI > SimpleWIFIServer
  • update wifi login creds
const char* ssid = "TP-Link_573B";
const char* password = "passowrd";
  • Tools > Serial Monitor

Youtube video : https://www.youtube.com/watch?v=UuxBfKA3U5M

pin out : https://www.studiopieters.nl/esp32-pinout/

esp32 wroom

Power consumption with 1 LED: 5V x 0.08Amp = 0.4 Watt