Task
- Individual Assignment: measure something: add a sensor to a microcontroller board that you have designed and read it
- Group Assignment: probe an input device's analog levels and digital signals
Indivisual Assignment
Input Devices
An input device is any hardware device that sends data to a computer or microcontroller, allows us to interact with and control it. The most comman example of an input devices on a computer are the keyboard and mouse ,in our case we will use some sensors or switch as our input device
For the start I chose switch as input device,to operate onboard led.
I design this file in eagle for designing I refered the datasheet of ATTINY45
In my input device board I used PB4(port B pin no.4 )for led , I used pull down resistor in between ground and switch
How switch works as a input:
When the switch is closed in the circuit, the input of the microcontroller is logic 1,but when the switch is open in a circuit, the pull down resistor pulls down the input voltage to the ground (logic 0 or logic low value).
For design & milling processs I followed the Eletronic design week
After milling I got the board like
I used simple program of ,when switch is presses led will on and when button will pressed again led will be off
the program for this operation is.
Error and solution
after uploading the program I got error led doesn't gets on after rechecking I understand that the button is not connected to IC pin then I connect it with jumper wire to pin no.PB3.
and it works.
Project part coverd
My aim to use this fingerprint sensor,because I want to used this as my input fot final project. Gt 511c3 fingerprint sensor because I want to use it in my final project
This sensor is one chip module with optical sensor & fingerprint algorithm ,I am using this sensor for verification of authorised user to the open the door of the key holder,so this is the first step towards it
First I download the libarary from intrnet for fingerprint sensor,then I connect this with arduino for trial, and programmed it for enrolling
Then I decided to run this sensor using my "hello Board",so I connect it with my board but error has occured
The error says "Serial is not declared"it means Attiny 44 doesnot includes serial libary,so to resolve it i wrote the programme by replacing the "serial " by "myserial" command .one more point I got ,while running this program on arduino this programme occupies more than 3 KB of memory ,so decided to move on next IC.
As we know Attiny 44 consist only 4 KB of programming memory
In my final project I want to use One fingerprint sensor,one lcd,around 27 switches so all this operations will consumes more than 4 kb space so I decided to used "Atmega 328" Ic as it consist of 23 GPIO pins and 32 KB of flash program memory.I designed and milled it.
Group Assignment
Then I used one LDR sensor module with my hello board
LDR
A photoresistor or light dependent resistor (LDR ) is a component that is sensitive to light. When light falls upon it then the resistance changes.
I connect this sensor's pin same as IR sensor and output looks
this sensor can detect at what distance object is, so for interfacing I connect it to "hello board"using FAbISP then I used arduino as ISP for programming then I used programed it and results on serial monitor and seriaI plotter
Changing values as per light intensity,on serial monitor
Changing values as per light intensity,on serial plotter
This week's group assignment is probe an input device's analog levels and digital signals other sensors hence we used sensors like ultrasonic sensor and LDR to measure physical quantity using Microcontroller board.
Ultrasonic sensors
As the name indicates, ultrasonic sensors measure distance by using ultrasonic waves. The sensor head emits an ultrasonic wave and receives the wave reflected back from the target. Ultrasonic Sensors measure the distance to the target by measuring the time between the emission and reception.
Summary
- I learnt about input devices.
- I understand the concept of serial port,programme memory.
- I learn how to check and display the result and graphs on serial monitor
- I leaarn how to select sensor and microcontroller as per our application
