Electronics Production

Link to class: Electronics Production FEB 13

For this week's assignment we made a FAB ISP and then program it. We had to made the carving on the plate, weld it to the different parts of it and then program it, test it and finally, get it to be recognized by the computer.

STEP ONE: Making the plate

Tools:

  • Soldering Iron with base
  • Lamp
  • Magnifying glass
  • Precission twezzers

    Materials:

  • Copper Plate
  • Lead for welding
  • Grease

    Parts:

  • 2x3 Jumper Header
  • Microcontrolator Attiny 44A
  • Resistor 1K
  • Capacitor 10 pF
  • USB mini conector
  • Cristal 20 Mhz
  • Resistor 10k
  • Zender Diode 3.3 V
  • Resistor 100 OHM
  • Resistor 499k
    IMPORTANT: Get help from a Fablaber. It is very important to have assistance while weldering and also programming, because although it seems fairly easy, there are some important tips you can miss because you haven't done this before and make this stage a lot harder.

    You can look at Henry Medina's Tutorial here.

    TIPS FOR BEGGINERS: I got this from my advisors at Fab Lab Lima.

  • Apply grease on ALL the plate. It makes it easier for weldering and all things to get attached ok. Then apply lead on all the plate, making a nice thin layer.
  • For me this was not very helpful, so you could also try to put a little "guide" points of lead on the plate, so you know where your parts go and also, to attach them first and then weld them right.
  • I believe one of the main issues on this assignment was the weldering of the parts, so you really need to use a magnifying glass and a precise weldering iron. And a lot of PACIENCE.
  • Another tip for this stage is to make a plate with the precise lines at the precise depth. If your lines aren't straight and not at a correct depth, then it's not going to work.
    I've made all of this mistakes, so I had to make two plates!

    First I produced the plate on the Fab Modules. A few mistakes where made here:

  • The plate was not the correct size, so I had problems plugin the usb mini conector for the testing.
  • Also, like I said before, the depth of the lines was not enough in some parts. So there was no connection between the parts and it didn't work.

    STEP TWO: Weldering the parts

    Then I had the plate and began the weldering.
    TIPS FOR BEGGINERS:

  • Make a list of the components you're going to use, write them down on a pice of paper and then put some adhesive double tape next to the names. Proceed to fetch all the parts and put them next to their correct name. So you have a list of the parts and also a nice way of register this for your web page.
  • Get an example of what you're going to do. In this stage your advisor can help you through it, and also, looking at some of the web pages of the Fab Academy from previous years. I looked at Henry's page from Fab Lab Lima.

    The weldering is fun, but the sad part comes when your plate doesn't work at an electronic level. The weldering part (when you already know what you're doing and how to weld ok) takes 30 minutes topx. Then you have to make all the parts are connected. Go to the computer and connect the usb. The first plate never did connect. My second plate had a little trouble at first with the usb mini connection and some other points, but then worked fine and finally the green light appear.

    Mistakes made:
    At first I used a weldering iron that was too wide and didn't use a magnifyer glass. I burn some parts and the weldering was terrible as you can see on the video above. Then I made another plate and began the process again. This time the plate was more clean and it did work, after a while. I'm beggining to perfect my weldering, one plate at a time.

    STEP THREE: PROGRAMMING

    Easiest part of this assingment. The problem here is that your usb mini connector is not weld ok. So you have to check that if it doesn't get recognized by the computer. First you need to install the software, and then it's about writing the commands to verify the whole process.

    In your computer at Ubuntu: Go to the terminal root. Copy this to install the Necessary Software for AVR Programming

    sudo apt-get install flex byacc bison gcc libusb-dev avrdude
    sudo apt-get install gcc-avr
    sudo apt-get install avr-libc
    sudo apt-get install libc6-dev

    Program the Fab ISP, locating in the firmware folder (one line at a time):

    make clean
    make hex
    make fuse
    make program

    Time of thruth: To verify if your FAB ISP is working correctly

    lsusb

    If your Fab ISP has been successfully programmed, you should see a list of the USB devices plugged into your computer. The Fab ISP will be listed in a line like the following:

    Bus 002 Device 004: ID 1781:0c9f Multiple Vendors USBtiny

    FabIsp vs. 2.0: SUCCESS!

    My first FabIsp wasn't working correctly. We though at first it was a Ubuntu matter, but clearly it wasn't. Although my FabIsp was flashing green, when I tried to program it, Error 1 appeared.
    After a long time from this assignment, I had the time to sit down and make another FabIsp from scratch, with all the knowledge I have now on working with the Roland Modela and soldering, the board was made and worked on the FIRST try!

    Some things I learned from this process:

    The lead drops on the board NEED to be shiny. If you wear them out by passing and passing the soldering iron over them too many times, its probable that your board will not work. Or you'll burn the components, which is even worst. Using the Modela is harder than it seems, but after you get the grip of it, it becames almost natural. Tutors need to be right next to you to help you out in every step. Here are the parameters I used for milling (Ricardo help me on this) :

    To PATH

  • Diameter: 0.3
  • Offsets: -1
  • Overlap: 0.2
  • 2d threshold: 0.6
  • error: 1.1
  • 2d (z): -0.05
    to RML
  • Speed: 6
  • jog: 0.1

    Soldering should be made with a lot of pacience, a lot of light and with a good Soldering Iron special for electronics. The one available at Fab Lab where not good, the tip was too wide, so it allowed for a lot of mistakes.

    Most common errors begin and end with the USB TINY. Make sure you weld it ok and do it first of all, because reaching to it its hard when all the other components are already welded.

    Although the board seems fine (connecting all the points) It doesn't mean you will be able to program it. I guess its a matter of practice, because It took me A LOT of boards to get to this point. Its what you get to understand once you already have taken the fab academy: You'll fail a hundred times before making success.