INPUT DEVICES

Goals:
measure something: add a sensor to a microcontroller board that you've designed and read it.

At the lab:
For this assignment I am going to measure the data coming from an accelerometer. First of all I will design the accelerometer board and then I will connect it to micro controller that I also designed.I want to read the data coming from the movements of the accelerometer and process it in a program.

I am using the following accelerometer: the ADXL345 from Digi Key. It is not so tiny as the one in the inventory but I'll try to use the one in the inventory in the near future after Fab Academy. The process of soldering this accelerometer it was quite painfull anyways. I explain everything in the Final Project.

The following pictures shows the design board that I have made for the accelerometer board and the stuffing of the components:








I had some problems soldering this board, at some point I realized I used the small pads for the capacitors and I had to solder some tricky capacitor in a way that does not look very alligned but at least works perfectly ok.

For the micro controller board I designed an ATMGEGA 328 based Arduino board.In the final project I am explaining the design process of this board and the different iterations that I had to do before arriving to the final design. Once I have them both I will connect them via serial and use an Arduino script to receive the data from the accelerometer. Let's see what happens.




After changing the values of speed in the script, I can get all the data without problems. This is a short video showing the data that is coming constantly from the accelerometer board. Only the X axis. As you can see the data is rapidly entering in the computer as the accelerometer is moving.




I also made an Input-Ouput board that is written in the Output assignment. It's an step response board and all the files and explanations are written there.

What I learned
I learned a lot about electronics. Making an accelerometer board from the very begining was a hard task for me. Also, I don't know why I choose to use one of the most difficults electronic input devices of a board: the really really small components. I face the fear of electronics with a tiny accelerometer, a very small component, probably the smaller of the whole invetory. That's why I had to use another one. The soldering part was the most difficult but with some patient I could do it. I recommend to start designing electronics with bigger components.

You can download all the files related to this week here.