Help for diagram of a line following robot

[Bob-Sto]

Hello everyone,

My project is to build a line follower robot from scratch, but with shaky electronics skills. I would like to have your opinion on the electronic diagram of the robot.

The robot has:

3 sensors (VL53L0X)
An OLED screen
A compass (HMC5883L)
5 sensors (QRE1113GR)
2 encoder motors

Thank you in advance for your help !

[hermit]

This forum is more about using the Kicad software than actual electronics. That said, if the schematic makes sense to you and any one else that needs to use it, that’s a good first step.

[3Dogs]

First thing - the VL53L0X is probably the wrong sensor to use.
It measures distance, not reflectivity.
You want a simple LED / Photocell, or a video camera.

[gmc]

You might have better luck posting on a general electronics forum like eevblog, but looking at the schematic the few things that stand out:

• The caps for the crystal on the atmega328 should be 22pF. 100nF is way too high and will cause issues.
• Add a resistor inline to the QRE1113 between pin 1 and 5V.
• Add some 100nF decoupling caps around the uC and HMC5883

[SteveT]

You sound like a university student - am I right?

If so, where did you get the schematic? Was it given to you by your lecturer? Or is it one you found yourself? Do you have to design the PCB as well?

Having to design and build the electronics, the mechanics, as well as writing the code, sounds a bit much for an undergraduate project. Perhaps you could tell us more about the context of the work?

[Bob-Sto]

Yes I am a French student, I created this diagram alone and I would like to have it checked then move on to the next stages of designing my robot.

[SteveT]

In that case go to EEVblog - there is a concentration of electronics experts there. Once you’ve got the design sorted you need to prototype it and test it to make sure the design is good.

When you are satisfied that your design is correct and works, then you need to think about designing a PCB. Come back here and you will get loads of advice.

[bertrand_meneroud]

you need to add decoupliung caps everywhere.
you should have One 100nF caps between your logic supply and the ground next tot each logic power supply pin of each chip.
You also need a bigger cap (at least 470uF) decoupling the power supply of the L290N (again close to the power supply pin of the chip.

You should have pull down resistor on the input line of te L298N, to make sure the motor is OFF, when you a reprogramming the processor.