Line Following Robot

Hi All,

In this instructable, I will share how to make a Line Following Robot using a kit from Amazon. I used this kit to teach my kid how to do soldering. Typically these kits are straight forward, you get all material, components, etc with the kit... and supposed to work flawlessly...

But the one I got, have PCB design issues and had to spend quite some time on it to troubleshoot. I will be sharing how to troubleshoot such kits at the end of this instructable

• Kit from amazon.in Link
• Soldering Iron
• Cutter
• Paper Tape

• We get both Chinese and English language manual with the kit
• I have a habit to sort and arrange each component so that it is easy to find during assembly
• We need a circuit diagram as a reference for troubleshooting

• Start soldering Resistors from the middle of the PCB moving outwards
• Remember, LED, Transistors and ICs are sensitive to heat, one must solder these quickly
• I use paper tape to hold components in place and then solder
• The LDR and red LEDs are connected in reverse, such that they are 5mm below the nut
• Connect each motor and battery pack and mark the direction of the motor
• Mark +ve and -ve on each motor, keeping in mind that one motor should rotate in clockwise and other in anti-clock
• Using double-sided tape provided in the kit, stick the motors and battery pack in place

Case 1: LEDs don't switch on, Motors do not switch on

• Check if all the soldering contacts are proper
• Using a multimeter test circuit connection, resistance and voltage drops
• on my PCB I found that the ground was not connected to the leds and sensors
• I used a jumper wire

Case 2: Copper traces

• The PCB is not good quality, so check if that component is properly soldered
• The traces come out due to excessive heat
• May have to solder extra jumpers

Case3: Motor direction

• There is a possibility that when you switch on, the robot goes in a random direction
• This happens because the motors are going in a different direction instead of going forward
• Disconnect one motor and test the other motor is moving in the forward direction, if not, then reverse connection
• Then fix the other motor with the correct polarity
• There are 2 variable resistors to adjust the sensitivity, use them

• The kit comes with a small track on which you can test the robot
• Once happy use a large chart paper or cardboard
• Draw 15mm to 20mm thick tracks on it
• Switch on and play