WEEK 13

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WEEK ·13·

INPUT DEVICES

INDIVIDUAL ASSIGNMENT

1. measure something: add a sensor to a microcontroller board that you have designed and read it

1. MAKING THE PCB FOR A LIGHT SENSOR

To make the PCB we use the machine Modela and the Fab Modules that already is installed in the computers of the FabLab Esan.

This is the Traces file.

This is the border file.

First we will do the traces. We upload the file by clicking load.png, then in the top menu we choose mill traces 1/64 and we make make.path, 0.1 error (pixels). Then place make.rml to calculate the time. This plate is quite small so it does not take long (8.6 minutes). Before starting, you have to place the origin point.

Once the milling process is finished a screen like this appears where the drawing of the board is totally in red color.

This is how you see the process of milling the PCB

The PCB this week is small compared to other boards.

For this board you need: 2 resistors of 10k, pins for Ftdi, Isp, Attiny of 45, capacitor of 1uF3 and 1 sensor of light.

This is how the PCB looks once soldered. The white piece is the light sensor.

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2. PROGRAMMING THE PCB (LIGHT SENSOR)

To program the PCB we need a 5v FTDI And our week 4 FabISP. I bought an FTDI and it worked for uploading the programm

To configure the sensor you have to do the following: have the .c and .make files in the same folder, from that folder right click and open the Terminal. On the terminal place the following: hello.light.45.make program-usbtiny to upload the program.

The process takes some time.

Finally, a message "done. Thank you" appears and the program is now uploaded to the PCB.

The next thing is to execute the Python file to visualize what is being sensed. The blue part shows the amount of light reaching the sensor.

Here the figure shows that there is no light reaching the sensor.

To run the Python file I had to switch from FTDI. The one I bought did not allow Python to run. The FTDI 5v. from the Lab worked without problems.

This is another test.

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3. HALL EFFECT SENSOR

For my final project I designed a board for a Hall Effect sensor. My final project is a suspended lamp that has movement up and down. The hall effect will serve to define the up and down stops. In this image you see the .sch file worked on Eagle.

In this image you see the .brd files of Eagle. It is a very small board and easy to make, it only has 3 components.

Export the files as .png This is the interior file for mill the traces.

This is the edge .png to cut off the traces.

Opening the FabModules installed on a FabLab Esan computers I could mill and cut out the traces. In the image you can see the configuration of parameters

Milling the board takes about 4 minutes and cut it out about 2 minutes.

To mill the traces i used a 1/64 drill bit.

To cut off the board i used a 1/32 drill bit.

Then i soldered the components. The black one is the hall effect.

I did a programming test using Arduino.

This is my electrical scheme of my final project. I did two Hall Effect sensors.

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DOWNLOAD FILES