print to thermal printer

see thermalprinter

about Timers

i2c two Arduino's

TVOut etc.

MIDI input

Pinout diagram


Serial Bus Contention: no more than one transmitting device

serial readLine

char buf[100];

bool readLine(char *buf) {
  static int index = 0;
  while (Serial.available()) {
    byte ch =;
    buf[index] = ch;
    if (ch=='
') {
      buf[index] = 0;
      index = 0;
      return true;
    } else {
  return false;

void update() {
  if (readLine(buf)) {
    Serial.print(" ");

MACRO for printing multiple arguments with sprintf

#define ECHO(s,x...) { char buf[100]; sprintf(buf,s,x); Serial.println(buf);}

Shift registers

Ethernet Shield v2

Arduino game consoles

driver for DCcEle DCcduino UNO

use avr-gcc without Arduino IDE

export PATH=$PATH:/Applications/


Arduino socket server forwarding all data received on Serial port to all connected clients

Mini USB adapter layout

Arduino Wake-on-LAN

Arduino button matrix without resistors or multiplexer


sprintf(charBuf, "%d,%d,%d", 5,3,2);

float to char[]

dtostrf(floatVar, minStringWidthIncDecimalPoint, numVarsAfterDecimal, charBuf);

arduino mini USB


sdi12: protocol om over 1 draad half-duplex communicatie te hebben. Er is een Arduino library voor.

seeeduino atmega328 via avrdude

avrdude -cstk500v1 -b57600 -p m328p -P /dev/tty.usbserial-A600JGJZ -D -Uflash:w:Globe4D-demo-firmware.hex:i

detect arduino bootloader

if self.sendMessage([0x10, 0xc8, 0x64, 0x19, 0x20, 0x00, 0x53, 0x03, 0xac, 0x53, 0x00, 0x00]) != [0x10, 0x00]:

rotary encoders

terminal mode

avrdude -c usbasp -p atmega1280 -t
>> dump flash 0 512
>> dump eeprom 0 16
>> write eeprom 0 1 2 3 4
>> erase
>> d hfuse
>> d lfuse

more: use -u to enable writing of fuses

reset fuses?

not sure

sudo avrdude -p atmega1280 -c usbasp -P usb -v  -U lfuse:w:0xef:m -U hfuse:w:0xc9:m

bootloader with avrdude

/Applications/ -C/Applications/ -v -v -v -v -patmega1280 -cusbasp -Pusb -Uflash:w:/Applications/ -Ulock:w:0x0F:m 

AVR documentatie

coder's toolbox for storing strings in variables


zie [[wifly]]

watchdog arduino

Ik heb pas zelf een [[|watchdog timer]] gebouwd voor Arduino met de TimerOne library zie ik nu. Maar het kan ook met standaard avr functies. Zie [[|dit voorbeeld]].

#include <avr/wdt.h>
wdt_enable(WDTO_8S); //start watchdog set for max 8 seconds
wdt_disable(); //turn off watchdog timer - if sketch gets this far it hasn't hung


locatie van arduino hex file

Op mijn mac was dit de locatie van de hex file:

cd /private/var/folders/n9/n9UpGCFsHQW0bdm5gfLoRE+++TI/-Tmp-/console4814829202509611846.tmp

Dit heb ik uitgezocht met lsof | grep -i 'tmp' (list open files).


op windows (afkomstig uit Ultimaker marlin firmware upload.bat):

@echo off
set /p COMPORT=Which COM port to use for uploading (ex: COM5)? 
mode %COMPORT%: DTR=on > NUL
mode %COMPORT%: DTR=off > NUL
avrdude -c stk500v2 -b115200 -p atmega2560 -P %COMPORT% -D -Uflash:w:firmware.hex:i

avrdude commando

./avrdude -c arduino -b115200 -p ATMEGA328P -P /dev/tty.usbmodem411 -C avrdude.conf -D -Uflash:w:firmware.hex:i

avrdude: parallel port access not available

avrdude: parallel port access not available in this configuration
avrdude: error at avrdude.conf:531: programmer type not specified

in het geval van deze melding kun je alle 'type = par' in de avrdude.conf vervangen door 'type = serbb'. Ook al gebruik je de profielen helemaal niet. Zie [[|deze]] forum post.