How to make a line follower robot without a development board | LDR based line follower robot
Hello and welcome back. In this project, we will learn how to make a line follower robot without a development board. I have used the LM393 Voltage Dual Comparator as the main component for that. Additionally, I used two Light Dependent Resistors (LDRs) and LEDs to detect black and white surfaces. This setup allows us to measure resistance changes based on the surface’s color. When the robot is on a black line, the light reflected to the LDR sensor from the LED is low, increasing the resistance. Conversely, when the robot is on a white surface, more light is reflected, reducing the resistance. We use these resistance values to control the robot’s gear motors via the LM393 Voltage Dual Comparator. I’ve also designed a custom PCB for this robot using JLCPCB, eliminating the need for messy wiring. Also, you can power this robot using two AA batteries.
How does work this robot?
When powered up this robot, one motor rotates forward, pushing the robot to one side. When the LDR sensor on that side detects the black line, the motor stops and rotates the other motor forward, moving the robot back to the other side. Then again when the LDR sensor on that side detects the black line, the motor stops and rotates the other motor forward, moving the robot back to the other side. The robot continuously repeats this process, allowing it to follow the black line smoothly.
What is the LM393
The LM393 is an integrated circuit featuring two internal operational amplifiers (op-amps). These op-amps are designed to perform various tasks using a single power supply or split power supplies. The LM393 is versatile and can be used in battery-powered systems, analog-to-digital converters, limit comparators, time delay generators, and more. It’s particularly useful for projects that require precise voltage comparison and control. For more detailed information about the LM393 and its applications, please refer to this link.
Features of LM393
- Wide Single−Supply Range: 2.0 Vdc to 36 Vdc
- Split−Supply Range: ±1.0 Vdc to ±18 Vdc
- Very Low Current Drain Independent of Supply Voltage: 0.4 mA
- Low Input Bias Current: 25 nA
- Low Input Offset Current: 5.0 nA
- Input Common Mode Range to Ground Level
- Differential Input Voltage Range Equal to Power Supply Voltage
- Output Voltage Compatible with DTL, ECL, TTL, MOS, and CMOS Logic Levels
- ESD Clamps on the Inputs Increase the Ruggedness of the Device without Affecting Performance
- NCV Prefix for Automotive and Other Applications Requiring Unique Site and Control Change Requirements; AEC−Q100 Qualified and PPAP Capable
- These Devices are Pb−Free, Halogen Free/BFR Free, and are RoHS Compliant
OK let’s do this project step by step. The required components are given below.
- LDR x 2 — Our store / Amazon
- 5mm LED x 2 — Our store / Amazon
- 103 Preset x 2 — Our store / Amazon
- DIP switch x 1 — Our store / Amazon
- Two-pin terminal x 3 — Our store / Amazon
- IC base 8 pin x 1 — Our store / Amazon
- LM393 voltage dual comparator x 1 — Our store / Amazon
- 47 ohm Resistor x 4 — Our store / Amazon
- 33k ohm Resistor x 2 —Our store / Amazon
- 1k ohm Resistor x 2 — Our store / Amazon
- 10 ohm Resistor x 2 — Our store / Amazon
- S8550 Transistor x 2 — Our store / Amazon
- 100uf capacitor x 2 — Our store / Amazon
- 3mm LED x 2 — Our store / Amazon
- AA battery holder x 1 — Our store / Amazon
- Nut and bolt — Our store / Amazon
- Gear motor x 2 — Our store / Amazon
- TT motor wheel x 2 — Our store / Amazon
Disclosure: These Amazon links are Affiliate links. As an Amazon Associate, I earn from qualifying purchases.
Step 1
Firstly, identify these components.
Step 2
Secondly, let’s order PCBs for this robot. For that, follow the steps below.
- First, go to the JLCPCB official website and log in to your account. If you are a new customer, please use my link here to register and get a $80 new user coupon.
- Now, click the instant quote button and upload the Gerber file. You can download it using the link below.
- Gerber file — Download
- I have ordered 10 PCBs with Red color. You can change it as you like. Then, select the build time and shipping. Finally, click the save to cart button.
Step 3
Thirdly, when you receive your PCB package, unbox it and solder the robot’s top side parts.
Step 4
Now, install the nut and bolt on the front of this robot. This bolt acts as a front wheel.
Step 5
Next, attach the LDR sensors and LEDs. Solder these components so that they are slightly below the bolt. For that, use the images below.
Step 6
Now connect the wheels to the gear motors. Then install them on the bottom side of this robot. Use pieces of double tape for that.
Step 7
After that, put the wires through the holes and connect them to motor terminals.
Step 8
Next, install the battery holder and connect it to the power terminal.
Step 9
Now, install the LM393 IC on the IC base. Then put the batteries into the battery holder and power on this robot.
Step 10
Finally, check the motor rotation direction. If it is incorrect, change the wire position. Also, you can adjust the sensitivity of this robot by rotating the presets. Now you can test this robot using a black line on a white surface. Ok, enjoy this project. The full video guide is below. So we hope to see you in the next project.
Troubleshooting
- Identify the health of components.
- Check the motor directions.
- Check the sensitivity values using presets.
How to make a line follower robot without a development board | LDR based line follower robot
