7

Electronics design

What I learned: I redraw a board, adding a button to turn a LED on and off.

Sources and inspiration used:

What I did: First as a group we tested the equipment to observe the operation of a microcontroller circuit board. What this board will do turn on and off a light while pushing a button.

I'm still a newbie designing, so I decided to build a simple circuit, with big routes (so it would be easier for me to weld. I looked on the Internet what each pin made for the Atiny45, so I could connect it to either the Led or the button. Once I managed to connect everything, I started to make the routes, it was difficult at the beginning because I had to be able to make paths that didn't overlap, and that was quite a task for me.

Then downloaded EAGLE, a PCB Design and Schematic Software from Autodesk. I chose to use Eagle from Autodesk to design because it is very visual and somewhat easy-to-use PCB design and schematic software. After that I used Neil's Hellow Board as inspiration.

This circuit has a TINY45-20-SMT, (is the micro-controller) Pinhead 1x08 (to connect it to power and also to connect it to the programmer so I can later on program it), two Resistors R1206, tact and a LED_1206 (to turn it on and off). I tried to use mods.cba.mit.edu to cut the circuit, but mostly with the drivers, so I had I used the milling machine. A tact is a button, so when pressed it sends information to the program to do different things, like to turn on a Led.

I also had trouble trying to cut the circuit, it wasn't well attached and it moved. When I tried to program the circuit I realized that the design was not the best, therefore I couldn't program it. But later on I was able to reflow the solder and program it. Sadly I didn't take any picture of that.

I used an internal oscillator, that's why I didn't use a crustal. I tried to use a Fab Modul, but I had trouble with the drivers and thats why I had to use the old version. I also calculated the resistance for my LED with the formula V=ri. In the data sheet I cheeked that the maximum current is 100 ma, and because I don't like working with the maximum of energy I calculated that a resistance of 100 could work with 50 ma because it has 5V, working to half it's capacity.

On the other side, the button has a high resistance in pull down mode, so when it is pressed the button read a HIGH.

Click on the image

to download file

Click on the image

to download file

Here you can visualize the Atiny Pinout

The resistors needed have a value of 220 ohms and 10 ohms (the number written on each is 2200 and 1002). The resistor above the takt has the value of 1002