I’m building a small Arduino robot project (a fire-fighting robot), and I’ve made a wiring diagram in Fritzing. Before I go further, I’d like to ask if my connections are correct and safe.
Setup:
Arduino UNO
L298N motor driver with 4 DC motors (3–6V) powered from 2 × 18650 batteries (≈7.4V)
A relay module (5V, 1-channel) to switch a 12V mini water pump (powered from 3 × 18650 batteries, ≈11.1V)
Sensors: flame sensors, ultrasonic module (5V)
A small servo for scanning
Could you please check if everything is connected correctly?
Do I need to add or change anything in the wiring to make it work safely and reliably?
Here is the Fritzing diagram I made (see attached file). fire mashine.fzz (223.1 KB)
There are a number of problems (and some bad parts) in your sketch. It is easy to make connections that don’t connect in breadboard. As a result it is a good idea to route schematic to make sure the circuit works as you expect. Several of your parts are breadboard only which makes that more difficult. A google search of the form “frtizing part part_description” for the LM298 and the gear motors should find parts that have schematic (both the current ones are breadboard only.)
In breadboard I right clicked on a ground connection (the scale here is not easy to see that though) which shows (as does schematic) that the battery is not connected.
The LM298s have no schematic connections so appear in the middle of the drawing and would need a part with schematic implemented to work correctly. The battery shows a connection on one side but not the other.
The second battery has no connections (due to the no connections in breadboard.) Neither the LM298 nor the gear motors have schematic implemented, there is a LM298 part that does and I expect the gear motors have one somewhere too (but I don’t know where, the google search should find them.)
Once you have replaced the misconfigured parts routing schematic will help check that breadboard is correct. If you don’t already have the LM298 board an alternate motor driver would be both lighter and smaller (which is important for battery life.) The LM298 will work, it is just not optimal (it uses bipolar transistors rather than MOSFETs in the H bridge which is inefficient and reduces battery life.
