Matia

I bought old used computer parts to build a working computer, I think in total it was about $60~75. List of components that I bought Asus p5kpl/1600 Mothboard Intel Pentium E7500 Nvidia GeForce 9600GT 500Watt Power Supply 160GB HDD 3x 1GB DDR2 RAM Computer Case Since the grapnics card didn't have the thermal grease on, I putted on. Then I installed CPU and the RAM to the motherboard.and then I putted the thermal grease on. When I was trying to install the motherboard, it didn't fit well because of the pins hitting something, So I desoldered the pin and bend it a bit. . After that Installed the grapnics card and the PSU. When everything was ready I tried to boot the system, but it didn't seem to work because I didn't hear the beep sound from the beeper. I googled for some answer and it told me to try to boot with only 1 RAM module installed, I tried it and it made the beep noise, but there was another problem, I bought this DVI to VGA adapte...

In order to build 555-timer-beeper you will need theses components - 555-timer ic - 1 mega ohm resistor - 1killo ohm resistor - piezoelectric buzzer - 100uf capacitor - jumper wires - Small batteries The circuit is a basic 555 timer astable mode. In this configuration the IC sends a brief pulse to the buzzer every few minute.

How it works This Line Following robot uses IR sensors to travel on the line. IR sensors work by using a specific light sensor to detect the light wave length that the sensor wants, which is Infrared(IR). The 3pin IR module that I've used has an IR LED that produces light at the same wavelength that the IR sensor wants. When an object is close to the sensor, the IR light from the LED bounces of the object and back into the sensor. This results in a large jump in the intensity.Since the sensor works by looking for a reflected light it can detect how bright the object is. For example, If  the an object white it will reflect more of the IR light than a black object. So it is possible to make the sensor return the value of the brightness, but in our project we are just looking for the black object which is the tape. Finally, what this all means, is that the IR module will detect if the floor is black or not and if it is black it will stop one of the wheels, which it will make the rob...

In this project, I used inverted switch. So when the door opens, it release the button and activates the circuit. The circuit is also very simple. 2 volts battery in series connects to the LED-strip that goes to the button and finally the button goes back to the LED strip. When the door closes it presses on the switch witch deactivates the circuit and when its released it activates the circuit.