ATMEGA16

COMPONENTS:

4 wire resistive touchscreen,

Avr developmentboard,

graphical Lcd screen.

DESCRIPTION:

      4 WIRE RESISTIVE TOUCH SCREEN      

                      The PSP touchscreen is a 4 wire analog resistive touchscreen. This means by touching the screen at one point, a resistance between each edge is formed for both the x and y axises. As you move your finger or stylus across the screen the resistance changes between opposing sides of each axis. By applying a voltage across each axis, a changing resistance results in a changing voltage. Thus a simple ADC on a microcontroller can be used to find x and y positions.

The four pins control 4 buss bars located around the peripheral of the touchscreen. In order to read either an x or a y position, two opposing bars need to be powered and a third orthogonal bar is used to measure the divided voltage.

This configuration means that the voltage, ground, and sense bar need to be continually switched in order to quickly read x and y positions.In our code v will need to switch between the x and y pin assignments in order to quickly read the x and y positions.

For this use 2 pins of port A as adc input and 2 pins of port D for +5V. Then write code such that it gives digital value of the x and y coordinate of the touchscreen on the lcd screen when the touchscreenscreen is touched at a particular point.

ALGORITHM:

FOR X-CORDINATE :

Declare x1 and x2 as output pins.

Declare y1 and y2 pins as input pins and take adc input from the pin connected to the adc port.

 FOR  Y-CORDINATE:

Declare y1 and y2 as output pins.

Declare x1  and x2 as input pins and take adc input from the pin connected

to the adc port.

INTERFACING WITH ATMEGA16 :

            In here connect x1 and y2 to the adc port of atmega16. In atmega16 full port A is adc port select any two pins as the required pins.

For x2 and y1 use pins of port D for giving high logic.

In order to read the value the DDR(direct addressing resistor) of resp. pin of port A is kept low. However while taking output the value of DDR is kept high like consider while measuring X coordinate : the DDR values of x1 and x2 are high and the value of DDR of y2 is low.

Also for PORT specifications consider while measuring X co-ordinate : the PORT  pin value of x2 is high and the value of PORT pin of x1 and y2 is low.

When code is written it is written in such a manner that it reads x value and then the y value so we have to continuously between the DDR values and the PORT values.

 PHOTOS OF LCD READING ADC VALUES:

BELOW ARE THE PICS FOR THE RESP. TOUCHS MADE ON THE SCREEN

1.

2.

3.

4.

Our Aim behind Building “Newton In Heights” was to Design of an Instrument which could give Dimensions & Deformation of any terrestrial structure, mainly for the application of the civil engineers for getting the dimensions of any building or structure.

Newton in Heights is an instrument which can be used to measure dimensions of any terrestrial structures like height, length, width, angle of inclination etc. The basic construction of this instrument is easily operable and rigid in nature. There are many instruments available in market which can measure the dimensions of structures like Theodolite and Total Stations but major drawback in using these instruments is there high cost, complexity and difficulty to operate.

If measuring is done manually it is very tedious and time taking job which can be done in the fraction of second using this device. Our main objective behind designing this is to measure all dimensions from a remote distant place and thereby creating basic block structure using the co-ordinates in any structure designing software like AutoCAD, etc. with simple calculations considering minimal cost, maximum accuracy and minimal human intervention.

Our Approach

• To Reduce Human Intervention during Surveying
• To Reduce Cost Of the instrument as compared to Theodolite & Total Station
• To Build an instrument considering college level experiments & field work
• To build a device that has maximum accuracy , minimal cost & minimal human interventions

Our Objective

• To calculate height, length and width.
• To calculate the degree of deformation in the structure.
• To calculate the angle of inclination & elevation.
• To locate the (x, y, z) co-ordinates of the basic block structure.
• Design the block structure based on the co-ordinates in any structure designing software like AutoCAD.
• To operate the device using wireless remote control.

……………………Stay Tuned for the Video Of  The Newton in Heights…………………………………………

Video:-

Things Required/Used:- Two Servos, acrylic sheets, ilabs development board, An Joystick and a good Labirinth game(I could not find a good labyrinth game so instead of using a Labyrinth game a mobile phone with motion sensor and Labyrinth game in it was used, thanks to Tushar for providing his phone and let it to stick it to moving platform without which the video would have been incomplete)

The Code is not really that difficult if you have worked with Servos before its really easy to understand but for those who dont know about servos I would like to give just a little bit information about them.

A Servo is basically a DC motor with restricted motion (90, 180, 270 deg commanly used) which has circuitary to control its rotation angle in that restricted limit. The Servo used in this Project was a servo with 180 degree angle control(As shown in above image). The Servos have three wires one data, one ground and one supply. Servos angle in very small increment can be controled properly by using proper pulse width at 50Hz frequency. The frequency is set to 50Hz and angle is controled by proper pulse width (or duty cycle) given in data sheets of Servos.

The Build consists of two servos connected to a moving platform and the moving platform is connected to fixed base using connector which was made using empty refil and paper pins. Most of the body part is made up of black Acrylic.

The joint used to connect moving platform to fixed base was made using straitened safety pins and empty pen refill.(Below are some images of joint).

Joint below fixed to base

Joint with attachment made of acrylic to connect to upper base.

The Joystick gives ananalog values of angle of Tilt in X and in Y direction, which is used to control angle of those two servos so tilting joystick in one direction will tilt the moving platform in same direction(The angle of tilt of Jotstick to moving platform can be adjusted by changing value of one variable in program for smooth operation or for increasing or decreating sensitivity). Below is the image of Joystick used.

Important Advice do not apply much pressure while drilling in Acrylic or it may break, happened with me and if possible use drill with less vibrations.

Image of final version  with body integrate with  ilabs development board inside built and joystick fixed to base.

Images after built was completed and Harshad sir and Rishikesh sir enjoying Playing with Labyrinth game…

HARDWARE :

Remote:

1) Accelerometer

2) iLabs CC Module (ATmega8+CC2500)

Console:

1) 5*7 LED Dot Matrix ( 4 )

2) iLabs CC Module (ATmega8+CC2500)

3) Microcontroller ( ATmega16 )

WORKING :

A microcontroller pin may output 5V that drives a single LED through a resistor and to ground.

The LED array arranges LEDs in rows and columns. The LEDs in the grid have their two connections, their cathodes and their anodes, connected to the other LEDs. By making these connections correctly, a microcontroller can drive any one LED on while leaving others off.

The LED at column 1 row 1 would be turned on if positive voltage is applied at C1 while ground is applied to R1. That single LED (C1 R1) would light up.

If, in addition to that, R3 was also at ground potential then the C1 R3 LED would also light.

You might work out that if we were to also light up the C3 R1 LED, that the C3 R3 will also light up, even if we do not wish to see it. There is voltage on C3 and ground on R3, so the LED is going to light itself.

To avoid that problem we can pick either a row or a column to light at a time. In this project, I control one column at a time. The microcontroller displays a pattern on column 1, and then quickly moves to column 2 with a different pattern. The microcontroller moves through all five columns and then continues to cycle over and over. Done slowly this is rather odd looking as only one column is displayed at a time.

But if the cycling happens quickly, then it appears to the human eye that the entire display correctly displays character.

I have connected columns of upper two LED grids to the respective columns of the lower LED grids and the rows of the right LED grids to the left LED grids. After these connections, the fours LED Grids together, can be considered similar as a single 10*14 matrix, conceptually similar to a 5*7 matrix.  This combination was necessary as, if not done, the number of pin outs would have exceeded the pins available on the microcontroller (ATmega16).

The remote consists an accelerometer IC, microcontroller and a CC2500 module. The analog output from the accelerometer IC is fed into the microcontroller. The internal ADC of the microcontroller converts the analog signal to digital which is then spend out wirelessly at the frequency and baud to rate through CC2500 module.

Aim:- To generate fast PWM and also to create menu driven program using LCD so on time changes are possible without having to plug it to computer again and again to make small changes

Components Used:- AVR Atmega 16 development Board, 16×2 LCD , Transistor(2222A), Connecting wires, RGB LED.

Working:-

Now the most important thing, you should know what an RBG led really is,

RGB stand for colors Red, Green, Blue and LED for Light Emitting Diode, it has four terminals out of a single LED one common(May be common anode or cathode) and other three Terminals to turn on particular color in LED.

The LED used in this experiment is of common anode mode(shown in Schematic given below) that is anode is common to all three. So to turn on a particular color on RGB LED we have to complete circuit by giving ground to cathode terminal of that color (Anode is always energized through 22 Ohm resistor).

This is done by using NPN Transistors (2222A), three cathode terminal of RGB LED is connected to tree different Transistors to their collector terminal and emitter is grounded, hence when we give positive pulse to base of transistor(2222A through 1K ohm resistor) cathode of particular color connected to that transistor gets grounded(as Transistor goes from Cut Off state to Saturation state) completing circuitry and remain on as long as positive pulse is given(To know more about this action just google Transistor as a switch)

Now as we don’t want to produce only RED, GREEN & BLUE color but produce wide range of different colors by mixing this basic color  so we are using PWM(controlling ON and OFF time of each color)

For this purpose PWM is generated on three pins(PD4, PD5, PB3) which is fed to base of three different Transistors through 1k Ohm resistor, and LCD is used so that real time changes are possible and also to see what values of PWM gives which color . For example if we want to create purple color we will mix Red and Blue color and adjust their intensity to get proper purple color.

Few photos of prototype:-

A complete view of prototype.

Closer View to Components on Bread board

(The LED is fitted with a syringe plastic cap just because  it looks good you can try a variety of different things like in video  a cylindrical paper roll is used )

Now as this was just a prototype the final product was completed soon after experimenting.

In final product instead of using Bread board a zero PCB is used (to avoid loose connections) and fixed tightly to acrylic board using nuts and bolt. Now you can just put variety of things on top of  it what you like to make it more attractive.

Project Members:- Pratik Sakode & Pratik Deshmukh.