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Standalone Arduino Programmer


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There is a short introduction video: See video

The standalone Arduino Programmer can program many atmel chip in stand alone mode which means it does not need a computer to operate. This is very useful for automating the programming of large number of chips.

This product is a shield for the Arduino Mega.

You will need to program the Arduino Mega only once with a computer then the programmer will be stand-alone and only need connection with a power source.


The principle is:

  • Program the Arduino Mega with the sketch provided below.
  • Flash the target sketch on a SD card
  • Insert the SD card / Connect the mega to the power supply.
  • Connect the shield to the target device with the 6 pin cable.
  • Press OK on the shield.
  • Target is now programmed.


  • Onboard Micro SD card.
  • 3 operation LED (work / ok / error).
  • 3 operation button.
  • 6 pin SPI connection to target.
  • Additional GPIO pins available for expansion.
  • Provision for use of a small LCD screen.


Preparing the programmer

  • Compile the target sketch on Arduino IDE.
  • Locate the produced hex file.
  • Copy it to the SD card.
  • Rename the file as 'firmware.hex'.
  • Insert the SD card in the programmer.


Production Usage

  • Connect the 6 pin ribbon cable to the target device.
  • Press the OK button.
  • Sucessful flash will be indicated with the green led 'ok'


Several firmwares that can be used on the programmer.

Atmega_Hex_Uploader_Fixed_Filename firmware

This is the basic firmware. It allows programming with the buttons and confirmation is indicated with leds. Download the firmware from this github repo:.

Choose the sketch named Atmega_Hex_Uploader_Fixed_Filename

A special version of SDFat library is needed. Download it from here below. Do not use the latest version of this library or compilation will fail.

  • Install the above library.
  • Open the Atmega_Hex_Uploader_Fixed_Filename sketch in the Arduino IDE.
  • Select Tools -> Board: -> Arduino AVR Boards -> Arduino Mega or Mega 2560
  • Connect the Mega to the usb port.
  • Click on Upload to write the programming sketch.


Only the OK button is functional. Press OK to start flashing the target. A sucessful flash will be indicated by the green LED blinking. Errors will be reported using the patterns below

Problems with SD card or programming target chip

Red x 1 = Cannot open SD card
Red x 2 = Cannot read file 'firmware.hex'
Red x 3 = Cannot enter programming mode in target chip
Red x 4 = This chip does not have a bootloader fuse
Red x 5 = Cannot read chip signature
Red x 6 = Unrecognised signature
Red x 7 = Bad start address in hex file for code
Red x 8 = Verification error

Problems with firmware.hex file

Red+yellow x 1 = Line in file is too long
Red+yellow x 2 = Line in file is too short
Red+yellow x 3 = Line does not start with a colon (:)
Red+yellow x 4 = Invalid hex digits (should be 0-9, A-F)
Red+yellow x 5 = Bad sumcheck at end of line
Red+yellow x 6 = Line not expected length
Red+yellow x 7 = Unknown record type
Red+yellow x 8 = No 'end of file' record in file
Red+yellow x 9 = File will not fit into flash of target

Credits to the author of this firmware who documented the usage here.

40 Pin Connector

The standalone programmer has a 40 pin connector forwarding unused pins of the Arduino Mega. The pin out is as as below.

Pin 1 is the top right pin.