Powering Arduino Uno

Hi,

I’d like to power my Arduino Uno with a 12V SLA battery and also include a basic SPST power switch between the Arduino and battery for ease of use.

The Arduino has the following connected:

2 Lm393 IR slotted speed sensor modules
2 Potentiometers
2 IBT-2 BTS7960 drivers. The Motors are powered by the SLA battery

I have the Pololu D24V25F5 5V 2.5A step down voltage regulator, here.
Could I put a power switch between this and the SLA battery then connect this module to the 5V and GND pin on the UNO? My only concern is the 5V pin currently has several wires spliced into it, to power the various components listed above. Would I just splice the powered 5V cable into these other 5V cables?

Or would it be better to buy another step down regulator (7V?) connected to the barrel jack of the Uno?

Any guidance would be greatly appreciated.

Michael

What is your concern, exactly? None of those components should draw much current at 5V. Use your multimeter to prove this. Even so, there's no reason not to distribute 5V from the DC-DC converter if that's convenient, or route it via the Uno board if not.

No point using a regulator to make 7V for the Uno's on-board regulator when you have a 5V converter and can bypass it. Convertors are almost always more battery efficient than regulators and generate less heat. Only in very low power circuits is a regulator going to be more efficient than a convertor.

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Can you post a diagram, or picture of a hand drawn diagram, of how you have your power supply configured and where you want to put the ON/OFF switch?

Thanks.. Tom... :slight_smile:

Thanks for the replies and apologies for not being clearer, I'm new to this.

The confusion is that the 5V pin on my Uno is occupied by a jumper cable which (due to lack of 5V pins) I've spliced into in order to connect the motor drivers, potentiometers etc all to that single pin. Same for the Ground which has a single jumper wire which I've connected all the grounds to.

Now that I don't want to power the Arduino with the PC USB cable anymore, do I just connect the VOUT from the step down regulator to that jumper cable plugged into the 5V pin? I've attached a diagram to explain things better.

The diagram also shows how I intend to wire the switch.

Many thanks,

Michael

Yes that looks fine. But first measure the current drawn by each component and post the results anyway, so we can check there definitely won't be a problem.

mikeoz, have you ever looked into Arduino Nano board and a breadboard to fit it in? You can have many 5V and ground holes when you jumper the power and ground rails to the 5V pin row of holes.

Also check out the Arduino Micro that can be programmed so the PC sees it as a game controller, mouse, keyboard or any combo of those as a standard HID.

If you get either one, make sure it has pins installed unless you like to solder pins. You can save a few $ soldering your own, sticks of pins are cheap by the bag.