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[Input Devices]-

Tasks for the week:

Assignments:

• -Measure something: add a sensor to a microcontroller board that you have designed and read it:

• -group assignment:

  Measure the power consumption of an iutput device

Measure Something

This week's assignment is to add input devices to a microcontroller board . As part of it, I designed a microcontroller board with temperature sensor .

Actually its kind of overwhelming for me to design a board by myself since I m not for the electronics background. My intention was to try couple of intput devices by myself. So I referred the board designs that Neil provided to design my board which integrates both of them. I used Attiny 44 microcontroller for mine. So there is quite a good amount of overall change involved in this design. This allowed me to figure out the needed changes all by myself.

There are number of sensor available on internet but i choose LM35 for my final project to measure temperature of heat retention box .

Reading data sheet of LM35 and attiny44:-

Electronics device which can get analog signal from out side and send to the controller and process it in digital signal (serial monitor in hexadecimal value) it know as input devices. Basically such kind of devices are get data from environment status and doing work as controller programmed language. This types of input devices are know as sensors.

Controller: (ATtiny44)

For this week I'm using Attiny44 micro-controller for controlling the sensor, For my final project i will use temperature sensor (LM35DZ) for detecting the temperature and after get this data out output device will be stops. Before going to schematic design first I read datasheet about Attiny44 and figure out how i design my schematic

Sensors (LM35DZ) For this week i used temperature sensor, model LM35DZ. this is the give most accurate data from the other sensors have. First i read the data sheet and take some clear info about the LM35DZ.

Sensor LM35

1-LM35-temperature sensor datasheet

Description

The LM35 series are precision integrated-circuit temperature devices with an output voltage linearly-proportional to the Centigrade temperature. The LM35 device has an advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to subtract a large constant voltage from the output to obtain convenient Centigrade scaling. The LM35 device does not require any external calibration or trimming to provide typical

Features

Calibrated Directly in Celsius (Centigrade)

Linear + 10-mV/°C Scale Factor

0.5°C Ensured Accuracy (at 25°C)

Rated for Full −55°C to 150°C Range

Suitable for Remote Applications

PCB board design:

PREPARING THE BOARD:

After understanding the ATtiny 44 then I prepared the schematic of the circuit using Eagle. and mill and cut the traces. To fabricate board I referred Electronics Design assignment

Note:-Some times the auto routing option keeps the traces thickness at 0.25mm which is not desirable for board milling. Hence it is always recommended to check the thickens of the traces by converting the board to .dxf format. Open the dxf file in Auto CAD and check the width of the traces as shown in th below image.

Milling and Cut Traces:

Milling and Cut Traces:

After finishing my routing I was exporting my eagle file into the png file. I Milled that board by using modella machine. As I mentioned earlier in Electronics Design assignment .I was using 1/64 bit for milling and 1/32 for cutting the board.

Final Milling and Solding:

List of components

Attiny 44
LM 35
1k SMD resister
10k SMD resister
resonator
Green LED
Male connector

I had some problems with my schematic design. Due to wrong package selection i can not solder part i have chosen hence i used two jumper wires. because The trace was not going from the trek of the IC was to small.

Programming

In programming I decided to use Arduino board as ISP to program my input device. and arduino IDE as GUI. because i have use arduino board and IDE in Embedded programing assignment

Interfacing of Attiny44 with LM35

First I connected the Arduino board to my computer. I uploaded sketch Arduino as ISP to make the Arduino board as a programmer to program my Board. and then connect input device :

	I soldered jumper pins at the arduino program.

LM35 (ACTIVE)±0.5°C Temperature Sensor with Analog Output with 30V Capability

Once the uploading gets completed the window as shown below will give as message that uploading is completed. This completes making the "Arduino" board as a programmer. I disconnect the board with my computer

I have written the below code for the operating the temperature of the board.

fest time high temperature and then change temperature sensor-	After change temperature sensor-

The testing of the temperature can be seen in the video:-

-group assignment:

Measurement of temperature sensor using arduino, Oscilloscope experiment:

Measure analog Levels and digital signal. (using DSO- Write about you understanding)

These include a variety of sensors, switches, controllers etc The input devices we had chosen to work with were various sensors, and the methods by which the data from the sensor could be analysed. The methods known to us were..

	The oscilloscope can be adjusted so that repetitive signals can be observed as a continuous shape on the screen. A storage oscilloscope allows single events to be captured by the instrument and displayed for a relatively long time, allowing observation of events too fast to be directly perceptible.
	A particular sensor basically measures the relative difference between the parameters specified to it, for instance, the example shown below is of a Sonar sensor which generates high frequency sounds(above 20Khz), and then calculates the distance from which it reflects.

Learning Outcomes-

In this assignment I learned about Input Devices which is really best for experiment the Input Devices and ,Programming Good experience in gurp work.

To download my files click here