1. Design a termperature board
2. PCB soldering
3. Temperature PCB programming
4. Selft evaluation
5. File download

1. Eagle software.
2. Milling machine.
3. Electronics components.
4. Welding station.
5. A AVR o FabIsp Programmer.

For this assignment I need to measure something: add a sensor to a microcontroller board that you have designed and read it

I decided to make a termperature board using fab academy tutorials

As I explained in assignments before, for design a electronic board I recommend to use a eagle software, now it is free you only need to have a autodesk account.

On Academy Input device tutorial teach you how to make a temperature board but I decided to re-draw that board, one change that I've done was "grounded board"

You can see the final design on the next picture

The components that are necessary to make this termperature electronic board are:

1. NTC sensor.
2. Resistor 10k Ohms.
3. Attiny 45.
4. FTDI connector.
5. AVR connector.
6. Capacitor 1uF.

On the list the only new component that I don't know is the NTC sensor, others are same components for other applications

This sensor has one thing on particular, resistance decreases with increasing temperature.

NTC stands for “Negative Temperature Coefficient”. NTC thermistors are resistors with a negative temperature coefficient, which means that the resistance decreases with increasing temperature.

They are primarily used as resistive temperature sensors and current-limiting devices. The temperature sensitivity coefficient is about five times greater than that of silicon temperature sensors (silistors) and about ten times greater than those of resistance temperature detectors (RTDs). NTC sensors are typically used in a range from −55°C to 200°C.

Read more http://www.resistorguide.com/ntc-thermistor/

Read more http://www.amwei.com/news.asp?news_id=88

I made my PCB in the CNC milling machine

Finally temperature electronic board look like next picture

I use the data sheet of attiny45 to know the features of ADC (Analog Digital converter)

I can understan how de analog chanel is configurate

On this point is necessary to download next files, they are on fab academy webside:

1. hello.temp.45.make
2. hello.temp.45.c
3. hello.temp.45.py

Them, it's necessary to write next comand if you are using FabIsp:

- sudo make -f hello.temp.45.make program-usbtiny

and Finally run python program with:

- python hello.temp.45.py /dev/ttyUSB0

1. What worked:
   • I programed my temperature board with success
   
   
2. What did not work:
   • I had some problems with the calibration of sensor, because the example program did not explain clearly, how implement the equation of thermistor on the program.
   
   
3. Things to improve:
   • Put the zero and spam setting on the board
   
   

File download