Hello! we're a student building a line follower robot. And we're using the following parts:
TB6612FNG motor driver
ESP32 WROOM (could've use arduino instead, but already got this one from previous project)
x2 12v N20 Motors
3.7v 4500mAh Li-On
TP4056 (charging module)
x4 HW201 IR sensors
CN6009 Boost Converter
So what happened was, after we've assembled and to see if all connection are receiving appropriate voltage. Our motor driver became really hot to touch even after only a couple of second after turning it on. And from our initial analyzation, it might also damaged our ESP32 since the VIN pin is only receiving 3.2v instead of around 3.8v - 4v (we believe it should be around this range) plus the built-in LED on top was dim. We then test if there's a short between the motor driver pins and we've located that the VCC and GND has very low resistance when we compare it to another motor driver.
We're now having a problem as to what causes this issue. Below is our schematic and the pcb layout we're using.
This might also be a good time to ask for recommendations/advice if we overlooked something. We have very limited knowledge about arduino and our first time doing a line follower so an advice is greatly appreciated. Thank you so much!!
There is a serious problem with the circuit, but you have not posted enough information about the circuit or the motors to guess. The schematic is far from complete.
If this is a commercial design, please post a link to the product page and/or user manual.
If it is a design your group has put together, you need to provide the specifications and/or links to all of the modules and parts, including the battery, charger, boost converter and motors. The design should have been thoroughly tested before ordering a PCB.
2 to 30cm adjustable sensing range (on-board Potentiometer)
35-degree Detection Angle
LM393 Comparator Selection Output
Easy to use
Please note that the sensor sensitivity varies depending on the reflection surface applied
Specifications
Main Chip: LM393
Detection Distance: 2~30cm
Detection Angle: 35 °
Working Voltage: 3.3V~5V
Board Size: 31 * 14mm / 1.22 * 0.55in
Board Weight(1pc): 3g
20mA supply current
Pinouts of HW201 Module
Pin Name Description
VCC Power Supply Input
GND Power Supply Ground
OUT Active High Output
Motors:
Manufacturer Fielect
Part Number FLT20191204D-1062
Item Weight 0.634 ounces
Dimensions 3 x 1.9 x 0.1 inches
Color DC 12V 1000RPM
Material Metal
Voltage 12 Volts
Speed 1000 RPM
Battery:
Brand Name PKCELL/OEM
Model Number ICR21700 4500mAh
Battery Size 21*70
Battery type 3.7v ICR21700 Lithium battery
Capacity 4500mAh
Color green /blue /colorful
Cycle life more than 600 Times
If rechargeable Yes
OEM/ODM yes
We traced and etched the pcb ourselves. We managed to make it running with only a simple forward/reverse command from our previous test before switching to new layout. We've accidentally switch the output of the booster in our old pcb so we use jumper wires instead, but then decided to make new one for cleaner look.
Thanks, but there is still much needed information missing, for example, the details of the boost converter, and the schematic is incomplete.
A problem that most beginners overlook is that brushed DC motors briefly draw the stall current every time they start moving.
For your motor (datasheet) that is 0.67 Amperes, presumably at 12V. Multiply that by two gives 1.3A. The mysterious boost converter has to produce that by drawing about 1.3A * 12V/(3.7V * 0.85) = 5 Amperes from the mysterious square labeled U6 on your schematic. Note: 0.85 is a guess at the efficiency of the boost converter.
If the motor drivers are overheating, there is likely to be an error in the PCB, or defect in the soldering.
Aside from not labeling the U6 as our charging module (TP4056), what are other information I needed to add to our schematic? Honestly clueless going forward.
As one example of what is missing, the square labeled U6 cannot correspond to the naked TP4056 IC, which requires a number of other components to function.
Do you understand the seriousness of issue that I raised about drawing 5 Amperes from the square labeled U6?
Did you rigorously test the complete circuit before ordering a PCB?
Yes... I think. It's way above intended rating if our motor is drawing 5A.
What we've been thinking is to supply the battery directly instead and remove it if we need it to charge. Now for the testing, we only checked if we have a connection between the pins and traces and if it's receiving our expected voltages.
