With infrared (IR) sensors, you can build a line follower robot. The construction and operation of this type is the post’s subject.
Clicking in the button below will open the post about IR sensors.
Line follower with transistors
It is possible to build a line follower robot with only 2 BJT transistors. The necessary materials are:
- 2 TIP122 transistors;
- 6 resistors: 2 of 47Ω, 2 of 330 Ω and 2 of 10 kΩ;
- 6 1N4007 diodes;
- 2 TCRT5000 IR sensors;
- 2 wheels and 2 DC motors with reduction;
- 4 AA batteries and support for 4 batteries;
This is the electronic part’s schematic circuit. When the phototransistor receives the reflected light from IR LED, the TIP122 transistor is in cut mode and motor stops moving. The 47 Ω resistor serves to avoid TIP122 from heating up. The diodes serve to reduce motor`s speed. If the robot goes too fast, it won`t be able to make curves.
This buttons opens the post about how to make printed circuit board.
The board after the processes of drawing, corrosion and piercing.
All components, with the exception of TCRT5000 were welded in the trails side.
The line follower robot ready. Follows a dark line in a light surface.
This is the test track, has 4.8 cm width.
Line follower robot kit
This is a D2-1 kit imported from China. These are all components, the board is the chassi.
The instruction manual shows the schematic.
This robot uses 2 LDRs and 2 red LEDs as sensors. Potentiometers are used to regulate the response of sensors. The sensor outputs go to the LM393 chip, which is a double-voltage comparator with two operational amplifiers. The operation of this component will be covered in a separate post. LM393 controls the 8550 transistors as switches and the latter controls DC motors, the D1 and D2 LEDs serve to indicate that the motor is on. This is the track test in opposite side of schematic.
This videos shows the follower line robots in operation.
This other video shows the assemble process.
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