I have always been fascinated by robots especially one with the wheels because they are cheap, easy and fun to make and play around with. Recently I came across a circuit in one of the books. It was a light sensitive led circuit based on 555 timer ic. I modified the circuit just a little to make a cheap light seeking robot. Let's see how i did it.
Step 1: Materials
To build the bot you will need the below mentioned components.
1. 2x 555 timer ics
2. 4x 10k resistors
3. 2x LDRs (Light Dependent Resistors)
4. A breadboard if necessary
5. Some wires
6. 2x motors (with wheels)
7. 2x 0.01n capacitor
8. 9v portable power supply
And you may also need a messy workbench.
Step 2: The Schemetics
The schematic diagram of this robot is very simple to understand. As I had mentioned earlier I just modified a circuit from on of the books to create this one. Make sure that the motor you use DOES NOT draw a lot of current.
Step 3: Chips On The Board!
Insert the ICs as shown in the figure. There will be a small notch or dot on every 555 timer ic. Make sure that the dots on both the chips should face upwards if you are going to build the robot as per the breadboard layout given in this instructables. Connect pins 8 and 4 together. Then connect pins 6 and 2 together.
Step 4: Power Source Layout
Connect pin1 to the negative rail on the breadboard. Connect pin8 to the positive rail on the breadboard. Do the same with the second chip.
Step 5: Resistors!
Now the most important part. Connect a 10k(brown, black and orange)resistor between the pins 8 and 6. Connect one more 10k resistor between the pins 7 and 6. Do the same with the next chip.
Step 6: Capacitors
Now connect a 0.01uf capacitor between the pins 1 and 5 of both the chips.