Week 1 - Principles and practices, project management Week 2 - Computer aided design Week 3 - Computer controlled cutting Week 4 - Electronics production Week 5 - 3d scanning and printing Week 6 - Electronics design Week 7 - Embedded programming Week 8 - Computer controlled machining Week 9 - Molding and casting Week 10 - Break Week 11 - Input devices Week 12 - Output devices Week 13 - Composites Week 14 - Networking and communications Week 15 - Interface and application programming Week 16 - Applictions and implications Week 17 - Mechanical design - machine design Week 18 - Invention, intellectual property and income Week 19 - project development

Week 6 - Electronics design

1. EQUIPMENT

The equipment used was:

SRM-20 MonoFab Roland

This machine is capable of cutting a wide variety of materials, including chemical wood, acrylic, and ABS. It is also capable of a range of accuracy settings from prototype to product design. In the last assignment i used

The maximun cutting area in the x-y plane is 152.4 mm x 203.2 mm ; and in the z directios is 71mm; for more details you can see the user's manual SRM-20

2. SOFTWARE

Electronic Design

Eagle is a powerfull software that provides quality PCB design, where you can use a schematic editor, layout editor to make an excelent design.

Eagle is a powerfull software that provides quality PCB design, where you can use a schematic editor, layout editor to make an excelent design. You can download de eagle schematic

HERE

This software help us to export the pads and trajectories in png format, and then it can mill the printed board circuit.

With the help of a tutorial about eagle, I made a new redesign, like I show below, I added a pulse switch, a led with its resistor, the value of resistor is 470 ohm.

At the schematic circuit, I modified it to insert a light emisor diode, resistor and a pulse switch, connecting the pulse sitch to the input pin of the microcontroller and led to the output pin, like I show below.

2. PROCESS

Fabmodules

STEP 1: enter the adress www.fabmodules.org into the search page.

STEP 2: click on the input format, you will see a menu, like i show below.

STEP 3: click on the image (.png) format, previously you export the circuit design make in eagle to png format, it will open a windows to search the png file, like i show below.

STEP 4: A window will show the circuit to print, like i show below.

STEP 5: click on the input format, you will see a menu, like i show below, where you have to choose the machine conected to your laptop, in my case I chose the Roland Mill (.rml).

STEP 6: Then choose the process, click on the input format, you will see a menu, like i show below, where you have to choose the machine conected to your laptop, in my case I chose the Roland Mill (.rml). Then click on the calculate button, and it show the trajectory of the mill machine to make a printed circuit board. But when I tryed to work with the SRM-20 with the fabmodule I had troubles and I didn't get to work with the SRM-20. There are some parameters:

                tool diameter(mm) = 0.4
                overlap(0-1) = 0.5
                intensity(0-1) = 0.5
                number offset= 1
                image threshold (0-1) = 0.5
                dut depth(mm) = 0.1

                Speeds: plunge = 2.0 mm/s
                        feed = 2.0 mm/s

Finally I use the lpkf mill machine and use the software in windows, this was a bad experience. however I made the pcb, like I show below.

At the end, after learn soldering superficial electronic devices I show below the pcb with the electronics components. The pcb is shown below, the dimension of this board is 45 mm x 40 mm.

I have any problems to mill the board, one of them was the board was not level and this meant that the router does not do a good machining depth and I did many boards until the routing was perfet. Another problem was the soldering, because I worked with a tin soldering station, and it's really dificult.