Electronics production

Assignment for week four (February 19, 2014)

The fourth week of the programme focused on Electronics production. The assignment was to make FabISP in-circuit programmer. So, since well I do not have a "fixed" FabLab - I do my projects in my Mobile FabLab. This is the first and only Mobile FabLab in South Africa, which I happen to manage. It is used as a vehicle to stimulate an interest and appreciation for science and maths studies among young people in both primary and secondary schools; particularly schools in both township and rural areas. The Mobile FabLab has all standard FabLab equipment except for a ShopBot.

Mobile lab

The evening of the last FabAcademy (Wednesday, 19th Feb), we experienced a lot of rain with severe thunderstorms. The thunderstorms caused blackouts in most residential areas and made roads un-drivable. On Thursday morning when I got to the lab, I discovered it was flooded with water, which damaged my machines.

flood pic 1  flood pic
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flood pic 3 flood pic 4













All my equipment had to be collected for repairs, and as such, I was taken out of commision due to the unavailability of the equipment and could not do the assignment. I am currently in the process of fully stocking our Soshanguve FabLab, so I didn't have access to what I would have expected to by virtue of the natural disaster. The Mobile FabLab was also collected to be sealed, by the manufacturer.

The lesson I learned from this experiece is to frequently assess an check the Mobile FabLab for any irregularities, and to ensure it does not get flooded again in future.

Check back next week after I get the equipment back on line, for this week's unit/ assignment.



So, it took me 3 weeks for me to finaly managed to do the Electronics production assignment. I finally recieved the components for the assignment and used the Soshanguve FabLab Modela to mill out the circuit board. 

The assignment for the week was to make a FabISP in system programmer for AVR microcontrollers. This assignment entailed milling a circuit board, soldering components on it and programming the microcontroller on the board. Out of all tutorials, I chose to use David Mellis' tutorial.

1. Communication between Modela and Mac

Initially, I struggled to get the communication between Modela and my mac going. I was using the USB-Serial port cable, but could not get the communication going. When I tried to send the "make.rml" to Modela, I got the error that read "could not open port /dev/ttyUSB0" - "Permission denied: /dev/ttyUSB0".

USB-Serial Port Cable

Looking up the error on the web, the suggested solution was to get permission to access the port which was found. This entailed adding my user account (lindi) to the dial out group. This was achieved by checking which group I currently belonged to. On terminal, I typed "group" which returned a list of groups available. I then typed a command "sudo gpasswd --add lindi dial out". I logged out and in again for the changed to take effect. This resolved my communication problem.

2. Milling the board
Board onto Modela

fabmodule  End mill

Board milled   End of milling   Final milled pcb

3. Populating the board
populated pcb

5. Installing the necessary software for AVR Programming
All went with this process.

6. Programming the ATtiny44
avrispmkii

programming success

7. Verifying that the ISP is working
FabISP recognised - Ubuntu
FabISP recognised - Mac

My FabISP device was successfully programmed and recognised by my Mac