week 6

to do this week task i will use autodesk eagle

eagle sketch file

Redraw the echo hello-world board, add (at least) a button and LED (with current-limiting resistor check the design rules, and make it

first i will do a sketch in eagle following the circuits showed below

to know what connect in which pin we are going to read the micro controller datasheet

in the schematic we will wire all the components

after we know the schematic and the components we will set the board parameters. the tool that we own have 8 mil diameter so for the design rules in eagle we will set this values to know what our modela milling machine can or can't do

finally we place the components and route the board to export the images that we will use in the modela milling to make the pcb as we did for the week 4 assignement

we solder and test the board

here you can find the links to download the files that i use

eagle boar file

week six

Electronics design

this is the circuit for the power regulator so we can connect batteries and it will regulate the voltage to 5 v used by the microcontroller the regulator uses two ceramic capacitors to filter the energy and make it stable for the microcontroller.

this is the circuit to connect a led to one pin in the arduino or the microcontroller, thanks to the led we can see digital outputs change from enabled to disabled. we use a resistor to limit the current in the led. here

here we have an image that shows that the voltage in the led variates depending of the color. using the ohms law we can calculate the limiting resistor

this is the button circuit that will work as an digital input so we can change the behavior of the board depending of the button state and how we program it. it uses a resistor that will set a state continuously in the input. the button will change the state in the input when pressed. we can configure the default sate with a pull up or pull down resistor. at left we have an image that shows both configurations. setting the pulldown resistor the default state will be ground or logic "0" changing to 5V or logic "1" when the button is pressed. setting the pullup resistor the default state will be 5V or logic "1" changing to ground or logic "0" when the button is pressed.

this is the icsp (in circuit serial programing) port configuration to be able to program the microcontroller. thanks to this pins the programmer can communicate to the microcontroller and write the code in the microcontroller memory

png to cut the board

png to mill the circuit

Carlos Pérez Ramírez