BUILD YOUR OWN PC OSCILLOSCOPE

Do you want to build your own oscilloscope then check out these links
using sound card


want faster one then check out this
using parallel port

refer pictures

INFRARED SWITCH

Hello friends !
I have finally managed long range wireless remote with a range of about 15 meters ! Infra-red switch/proximity detector/obstacle detector/remote e.t.c.

CIRCUIT DISCRIPTION
Transmitter:
I have used two ic 555 both in astable mode, one is used to produce a carrier of approximately 38 KHz nearly 50% duty cycle and the second another is used to produce data signal nearly 20 Hz alternate 1 and 0
Nearly 50 % duty cycle. The output of the data signal generator is connected to the reset pin of the carrier ic producing 38 KHz carrier to produce small bursts at the rate of 20 Hz.
Receiver:
Receiver is the most important part of this chain, I have used TSOP1738 (very sensitive) as the detector, read the datasheet before using it, the TSOP1738 is immune to unmodulated carrier 38khz infra-red, hence the 20 Hz data signal is used to modulate the carrier.The output of the TSOP1738 is given to a missing pulse detector which is basically IC 555 in monostable mode having time constant 1.1RC greater than 1/20 sec
Schematics and pictures are shown below

PARALLEL PORT INTERFACING

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Hello visitor !

This is my first PC interfacing project via parallel port, I have interfaced my RC car via parallel port .Although in this case I have managed readymade code for it ,you can also write your own in C language, it’s quite easy you have to use inport and outport instructions ,search on net for it.

You can control 8 bits at a time; here is the URL from where I got the code

Instead of the transistors used as shown in the site I have used ULN2003/ULN2803 as they prove cheap and easy to solder .Go through the data sheet of the above mentioned IC’s before soldering them .So what are you waiting for ?

OBSTACLE AVOIDING ROBOT

The above circuit is taken from robotroom.com. Visit the page for some interesting fun projects.


Hi junkers !
This is an autonomous robots which uses ultrasonic sensors (40 KHz), which can detect obstacles from 45 cm or less when ever it detects an obstacle it rotates its direction by 180 degrees .Well I am not providing any serious technical stuff because I am quite busy in my academics these days, but if you want to know it schematics more just plug on to Google for an hour or so. If you want to increase its range increase the power supply to 15 volts or increase the operating frequency above 40 kHz and for its faithful detection use more than one sensor.

My team-mates without whom the project would't have been possible:
1>DIVESH DAVE
2>SANKET GHOTEY
3>SAGAR GHOTEY

SCREWING WATER

WARNING: Imitating to construct this kind of boat may be dangerous. Self discretion advised.
This was our first attempt to make a boat totally from junk.We have used cell metal covering to build custom made propellers, ball pen refill and cycle spoke as crankshaft and two rusty motors one for propulsion and one for turning the boat. Styrofoam as chassis or base, an RF transmitter receiver and a 9 Volt battery. The basic catamaran design slices through when you don't have to turn.
Two of my friends with whom I shared the idea and motivation are:
1>Divesh Dave
1>Apoorva Karnik

STEPPER MOTOR DRIVER CIRCUIT USING D- FLIPFLOP

Hi junkers !
This is my first stepper motor driver circuit .At this stage I don't know microcontrollers. Hence I am using four D flip-flop in its logical circuit. Using a J-K flip flop IC to build a D-flip flop. First of all you should know some basics about stepper motor. The stepper motor is different from a DC motor
because of its following characteristics.
1>Its speed and displacement can be accurately controlled using timing circuit.
2>It generally has high torque.
3>Less efficient as compared to DC motor.
4>Easy to control using microcontrollers.
5&gt:Has mechanically robust and sturdy design.

There are basically 2 types of stepper motors.
1>Unipolar[5 wires](old design and easy to drive but heavy and less torque). Polarity of the coil need not to be changed in order to move the motor in one direction.
2>Bipolar [4 wires](new design and hard to drive but light and more torque). Coil polarity needs to be changed. i.e. you will need a H-Bridge driver to drive it.

These motors are quite costly nearly INR 250 and above (in Indian market). Hence a better way to get it is to get if from a printer service station or scrap market (electronics market generally printers).

The two logical ways the motor runs is as follows and to get more torque you have to excite both coils at the same time.
let the minimum torque be "X"
then the logic sequence is
[1][0][0][0]
[0][1][0][0]
[0][0][1][0]
[0][0][0][1]
now to get torque 1.44 times two coils are to be exited at the same time
therefore the torque increases to "1.44X"
[1][1][0][0]
[0][1][1][0]
[0][0][1][1]
[1][0][0][1]
component list:
ic 7473 JK flip flop-2
ic 7404 NOT gate -1
ic 555 timer ic-1
ULN 2003 stepper moter driver ic-1
5V power supply-1
12v power supply-2
LED's-4
resistors
10k-1
20k-1
capacitor 1 uF-1
PCB linear-1
Ic base 16pin-1,14pin-3,8pin-1.The circuit is quite simple. Basically a ring counter connected to a driver. The timing is controlled using IC555. A timing pulse is used to control the rpm of motor using ic 555 in astable mode (its operation is well discussed in IR remote control module) and a unipolar ULN2003 is used for driving the motor.

This circuit will work. Basically its a 4 bit ring counter connected to a motor driver. At this stage, I do not know how to use a schematic editor. I will post a better schematic once I learn to use it.

At all D connections of the circuit we connect the motor driver IC. Refer following link for generating a clock signal.

http://www.electronics-tutorials.ws/waveforms/555_oscillator.html

The astable output shown in link above is used as a clock signal.

Don't try to directly drive the motor using the flip flop signals. This is because the JK floip flop can source so less current (mA) that the voltage drops to zero when directly connected to motor.
Trouble shotting ?
1> The motor is just vibrating:
This is a verv common problem. To solve it you will have to increase the time period of the clock pulses.
i.e. decrease the frequency of timing pulses because the stepper motor take some finite time to rotate because of the rotor inertia.
2> The motor is running in zig zag pattern; check the logic sequence

MY BLACK BOARD CHALK CARVING