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Input Devices

For this assigment i had to measure something, adding a sensor to a microcontroller board that i designed. First, I decide to do a humidity sensor for kids. My goal was the design to be a bit more attractive for kids be more interest on it. I based my ideia on a previous student project (Ranpura - 2016 ). The first challenge was to design and understand how it would worked. To design i used photoshop and the Ranpura's png; modifying the shape of it. After doing it i milled it but i noticed i had a scale issue. I went back to my design and i fixed it. With the board milled i soldered it. For better undertanding of the process i decide to test it first with a Arduino. I had a lot of trouble doing it.


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After it, i used the Arduino examples to program it in a way the arduino could read it. After running the code i had to change the buttons status to LOW because the way i put the resistors. To get a more stable and clear data i had to change a few times the resistor.


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I end up giving up about that idea and started to do the input of my final project. It started to testing a noise sensor with arduino. For that i conect one cable in a digital pin, one in the ground, and one in the votage. I used Sound Detection Sensor Tutorial for the coding and better undertanding of the sensor. The ideas was when the sensor detects noise it trigge the servo motor.


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it was hard to make it work but after i get the right code and with the right calibration, it worked and it attivate the sever mottor attach to it. After i made my board, i used a satshakit tutorial. The reason i chose this board is explained in my final project documentation. So i followed the tutorial to make the board on eagle. The first try i put the wrong microcontroller and it end up not milling correct.


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I changed the button as a normal button and not a reset one in case my imput didn't work. I end up forgeting to put a pin just for the reset pin but i was able to program it doing the reset it manually (touching the pin with the cable).


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After all ready one the eagle, exported to a png. To make the holes i had to use the photoshop. For the first try i use black background to white hole, it made the holes to big and i had to invert it on fab module. I used the 1/32 tool to do it. With all the files ready i milled the board again.


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I started soldering the Atmega328p , to do it i used flux to fix better it on the board. To learn hor to use i followed this tutorial:



After i soldered i test the pins and i realise the VCC and the ground were connect but was not the pins. So looking carefull the picture and was a really small connection under the microcontroller because of the milling. So i had to unsolder it and break the connection. After i resold it and soldered all the rest. I test again and i had to change a led.
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After all, i was finaly able to make my board.


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With the board ready i had to bootload it, two of my classmates had the same problem to bootload the board so i just followed this two tutorial to do it with a arduino:

- Nick Gammon




With the help the tutorial i was able to bootload without much problem. After that i connect the FTDI cable to send the code.



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I was able to run the same code and make the sensor work!


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Here is the file.