Hi,
I would like to power Arduino UNO from 4AA rechargeable batteries
I wonder if there is a way to do it without risking the board (I understand that connecting the power supply directly to 5V pin can harm the regulator)
There is a safe way to do it ?
And, what is the minimal voltage that Arduino UNO can handle ?
Thanks!
The Arduino will run from 5 V down to about 1.8 V (at reduced clock speed).
Use of 4xAA NiCD or NiMH without a regulator is not safe, because the voltage can exceed the recommended maximum of 5.5 V.
The safest approach is to remove the voltage regulator and use 2 or 3 AA rechargeable batteries and the internal 8 MHz clock. It is easy to remove the regulator on the cheap Pro Mini boards from ebay.
Can I power the Arduino UNO from 5v pin and connect it and the ground to the regulated output of the l298N bridge motor when the setup is 2WD chassis that includes two motors, 9g servo and ultrasonic sensor and powered from 4AA Sanyo eneloop batteries?
Should it works that way ?
No real experience with RC cars, but everytime I see this same question pop up in this forum I wonder if people read datasheets.
The motor bridge mentioned "looses" ~2.5volt@1Amp motor current.
If you power that chip from 4.8volt, you have only 2.3volt left for the motor.
If you use a 5volt or 6volt motor, you should have 7.5 or 8.5volt available.
That would also make it easier to power the Arduino (Vin pin).
Leo..
It is rarely a good idea to power the Arduino from the motor power supply, unless you fully understand the phrase "power supply decoupling" and can build a circuit to do what is needed.
I wonder if there is a way to do it without risking the board (I understand that connecting the power supply directly to 5V pin can harm the regulator)
I've powered my old arduino directly from a 7805 regulator chip. The on board regulator chip was only dropping 12v to 8+v (the on board LED was noticeably brighter than usual, so I checked the voltage on the 5v pin with a multimeter). No apparent harm from using the external 7805 regulator chip, or operating the arduino at 8v for a short time.
operating the arduino at 8v for a short time.
A minor miracle that it survived at all, but it was undoubtedly damaged.
Eladh:
I understand that connecting the power supply directly to 5V pin can harm the regulator
You "understand" wrong then.
You really have to be careful what you read on the Internet.
Here's a thought.
Use a step-up power convertor like this to bring the voltage up to 9 volts or so. Then just power the Arduino through its regular power connector.
https://brainy-bits.com/shop/components/step-up-power-converter/
This one is just an example, you'll find several others on the net that would do the job just as as well.
Here's a thought.
Wastes battery power stepping up then down, so you replace them twice as often.
jremington:
Use of 4xAA NiCD ... without a regulator is not safe, because the voltage can exceed the recommended maximum of 5.5 V.
1.2 V * 4 = ?
1.2 is the nominal voltage. A freshly charged NiCD cell can be 1.5 V or higher.
1.5V * 4 = 6