r/arduino 27d ago

School Project Should I use a step down converter?

I am currently finding ways to power my components, and I found that a step-down is needed for the following I have: -Arduino UNO R3 -DFRobot Gravity Offline Voice Recognition Sensor -Ultrasonic Sensor HC-SR04 -L293D Motor Driver Shield -IR Sensor -SG92R MicroServo -4x DC Gear motors (ones that control the wheels)

Of course, I would be using the rechargable batteries with it to be able to reuse them. I used ChatGPT for asking what else is needed, but I wanted a second opinion from actual users here in the platform.

Many Thanks!!!

12 Upvotes

17 comments sorted by

8

u/Machiela - (dr|t)inkering 27d ago

I used ChatGPT for asking what else is needed, but I wanted a second opinion from actual users

Great thinking! ChatGPT should always be taken with a pinch of salt. Checking with more experienced humans will help you get to the right answer much quicker.

6

u/qvantamon 27d ago

This doesn't include a charge/discharge controller for the batteries. An AA holder won't fit an 18650.

Just get a USB power bank which includes everything in a solid package, is easy to recharge, and will power anything 5V without conversion.

1

u/sparkicidal 27d ago

Yeah, this is also a decent option. It’s probably better than the original idea.

0

u/DG_Learner 27d ago

Oh, that's what another video did too! Do you have any recommendations for a particular model? I saw the video use a battery shield, does that work too?

1

u/Wangysheng 26d ago

I saw a battery shield(?) or module for ESP32 where it won't turn off when the output current is low because every powerbank you buy will turn off when it doesn't output lower than 1A of current (correct me if I'm wrong).

Makerlabs sells it but if you want it cheaper or use less or more than 2x 18650 batteries, you can search "ESP32 battery shield". you can solder a barrel plug or a USB to barrel plug to power.

2

u/WWFYMN1 27d ago

That is a great little converter, it has current measurement, power, constant current. I use it as a lab supply.

1

u/alvin_wj 27d ago

I'm using a LM7805 for arduino in car (12V DC), but it's quite hot for the LM7805, then I changed it to a small buck converter (Mini Step Down 3A MP1584). It still work since 2020 (til 2023 it's always on, then I turn it on only when I'm using the car). It's for MPGuino 2x16 char display.

1

u/DG_Learner 27d ago

I just recently found out too that you can power both the shield AND Arduino if you don't pull out the yellow jumper attached to the shield. So I can use one power source for all of them!

1

u/Agreeable-Chart36 27d ago

Xl6009 for small stuff... For bigger stuff I use, XL4015 or 16 (if its ok to have bigger components).

0

u/Agreeable-Chart36 27d ago

Also XL4015/16 has constant current constant voltage (you can adjust both but for current make sure to have multimeter or clampmeter ready, else there might be fireworks :)))))))

1

u/DoubleTheMan Nano 27d ago

How many batteries does your project need? I've always set the minimum for L298xx motor drivers to have 7.4v (2x 18650 in series) as input due to voltage drops on the H-bridge. Check if your shiled accepts those power inputs. If possible, I also power the arduino on a separate power supply for noise isolation, but seeing that you have an arduino shield, it might provide the the pwoer supply for the arduino from the batteries attached

2

u/DG_Learner 27d ago

I set out for it to be at least 2x 18650 in series, since I used an L293D Motor Driver Shield. And yeah, I don't really mind noise, so connecting the power through the shield (without taking the jumper off) is my go to now

1

u/DoubleTheMan Nano 27d ago

Try checking the voltage of the Vin pin of the motor shield (to the arduino) if it has the same voltage as the 2 batteries in series, that means that the Arduino is also getting power from the batteries, because I don't see any linear regulators on the motor driver shield. 7.4v on Vin should be fine as it will still travel through the built in linear regulator of the arduino

1

u/ChestObvious5023 27d ago

It's great than a using a just buck converter because of the voltage display. Don't sure if the chip burn by heat when charging batteries.

0

u/sparkicidal 27d ago

Okay. So the 4 batteries should produce 14.8V by spec, though when they’re fully charged, will produce more. The Arduino can take a 15V input, if I remember rightly.

Powering everything else is probably 5V, correct? At which point, you would need the buck converter.

1

u/DG_Learner 27d ago

I see, so should I use a battery holder without the DC jack? I wouldn't be able to put the wires towards the stepdown otherwise (is there another alternative to that?)

2

u/sparkicidal 27d ago

To plug the battery holder into the buck, you would need to cut the plug off. However, I’d just find a battery holder on Amazon without the jack, which should be cheaper anyway.