How to Make Circuits in the Fab Lab

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Making a circuit requires several mini-projects:

Design and Architecture

Decide what function your circuit board should have

A good approach is to write down in words how the circuit board should work.

Create the schematic and board layout in a CAD program

Use e.g. Eagle or, ,or Gimp (drawing tool), Inkscape or Open Office or draw it with black pen and scan and trace. The gap should be the right size and shape.

Physical Fabrication

Machine the board

Physically milling or cutting out the board which connects components

"Stuffing": Solder components on to the board

Solder the components to the board. If you want to where the components should be you could look at the file design, in .cad file or you can check out

Microcontroller Programming

Make a programming cable

There are several different types of cables used to program the AVR microprocessor. The cables are different based on the number of wires used, the types of connectors on either end, and the program used on the computer for downloading hex code to the processor.

Write the Program

Write the program (in e.g. assembler or C) , compile the program so that the microcontroller will understand it -> Jan

Programming the microcontroller

If you are using the Fab Labs, AVR microcontrollers

-> Jan

Testing and Troubleshooting

Test the microcontroller

Plug the microcontroller in.

  • Is the power on?


If your board is not working, follow the step to troubleshoot it:

Check Problem Possible solution
Battery voltage Voltage too low Replace the battery
Microcontroller voltage terminals No voltage or too low (it should be around 3,3 V to 5 V for the hello boards)
  • Follow the track and check every component voltage (capacitor, voltage regulator)
  • Check the solder there is no electrical continuity
  • If the solder is ok, replace the component (Learn here how to un-solder properly)
Solder Doesn't do what I wanted
Code Doesn't do what I wanted Take a breath and review your code

If you cannot download your code to the microcontroller, follow the step to troubleshoot it:

Check Problem Possible solution
If the cable is done right Software avrdude gives error:
avrdude:AVR device not responding; 
avrdude: initialization failed, rc=-1 
         Double check connections and try again, or use -F to override this check.
  • Follow the Making serial cables tutorial to build a cable
  • Check for electrical continuity at the cables end
Permissions on accessing port 0 Error running avrdude:
avrdude: can't open device "/dev/parport0": Permission denied
avrdude: failed to open parallel port "/dev/parport0"

Type the following to see the permissions on the parallel port 0

ls -l /dev/parport0

Type the following to change permissions to users

sudo chmod 0766 /dev/parport0

Type the following to check if the permissions were changed

ls -l /dev/parport0

External Links