Input device

Task to do-In this week we have to measure something by adding sensor to a microcontroller board and we have to design that .

What is input devise-
Sensing and controlling current flow ,temperature,humidity is a fundamental requirement in a wide variety of applications .Devises which we use to sense parameters like temperature,current,humidity,light..etc and which provides this parameter to controller board in proportional signal form are called as input device.

What I have decided - I decided to make sensory system to measure current.I want to use it in my project as a input to microcontroller. I searched for current sensing with arduino and I got some ideas.
I found some information about current sensor ACS715.It's details are as below.
operation principal-    hall effect based
current direction-        accept uni direction current inpu
output-                         133mV/A(output is 500mv at 0current)
operating voltage-       4.5v to 5.5 v
error-                           +-1.5%

I searched for other IC's available for current sensing and Its circuits
I found some tutorials for projects based on current sensor . 

circuit diagram of acs715















The ACS712 current sensor is based on the principle of Hall-effect. According to this principle, when a current carrying conductor is placed into a magnetic field, a voltage is generated across its edges perpendicular to the directions of both the current and the magnetic field. This voltage is known Hall voltage and its typical value is in the order of few microvolts. The Hall voltage is directly proportional to the magnitudes of current and magnetic field. So if one of them (I and B) is known, then the observed Hall voltage can be used to estimate the other.

 I have used current sensor to measure load current .If load draws more current from the supply, current sensor will detect it and give alarm. And accordingly action can be taken.

 So as per pin connections- I provide battery ground supply to motors ground supply.Then connected positive supply at 1st end of current sensor and
and at 2nd we have to connect remaining end of motor.

This ACS715 has 3 wires-1.vcc
2.Gnd 
3.out 
So this sensor transfers current to voltage form.
I wrote program to buzzer when current exceeds than certain limit.
After connecting sensor to motor it gave readings as follow at no load condition.

amp=2.53
amp=2.50
amp= 2.54
amp=2.47
amp=2.50

When there was full load it showed
amp=4.3
amp=4.50
amp=4.53
amp=4.43
amp=4.2
amp=4.57    

For learning another sensors I go through ultrsonic and IR sensors.Both are obstacle detectors.

I edited my hello word board for input,output in assignment 6 as per requirement and Also made another input board but used hello word for actual programming as I did not got time to solder another one.The board designed for input and output is as below

 

Ultrasonic sensor:
Ultrasonic sensors are transceivers which convert ultrasonic waves into electrical signals and vice versa. Active ultrasonic sensors generate high-frequency sound waves and evaluate the echo which is received back by the sensor, measuring the time interval between sending the signal and receiving the echo to determine the distance to an object. Passive ultrasonic sensors are basically microphones that detect ultrasonic noise that is present under certain conditions, convert it to an electrical signal, and report it to a computer. Ultrasonic sensors are used in wide applications such as medicine, measurement of distance, length, depth etc.It has 4 pins vcc,gnd,eco and trigger.we can short eco and trigger or we can keep it separate
I have used ultrasonic sensor basically for detection. I have used it to detect obstacles and flashing light.


IR Sensors:
An infrared sensor is an electronic instrument which is used to sense certain characteristics of its surroundings by either emitting and/or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion. The infrared sensors are the sensors that detect/measure infrared radiation or change in the radiation from outer source or inbuilt source. Also sensors that use the property of infrared radiations to detect the changes in surrounding are termed as infrared sensors.It has 3 pins vcc,gnd and output


In this assignment I learned various types of sensors,types of sensors,How to use them and their programming.I understood how to calibrate sensor and learn how to choose sensor by seeing its datasheet because for sensing the same thing we will find various rage of sensors but we have to choose the right one by its specifications Resolusion,accuracy matters alot while choosing the sensor.I learned all this in input device assignment


Download all files of input programm(Current sensor,Ultrasonic sensor)
Download eagle files for board I used (edited hello world)
Download eagle files for input board
Download input board png