Best way to power Uno and Devices

Need some quick guidance.

I will be installing my Uno in a small electrical enclosure, but I am not sure the best way to power everything.

I have the Uno (of course) and 3 other devices that are 5 volts. With the possibility to add more 5v devices in the upcoming weeks.

It seems the best voltage for the Uno is around 7-9 volts DC, and I can input that into the Vin pin. But how to I supply 5 volts to my other devices? I do not want to power the Uno from the USB port either. It would be great if I could keep everything hardwired.

I did find some LM2596 power modules, which I thought of installing multiple modules feeding them with one 24VDC power supply, keeping all the GNDS tied together.

Thanks

Instead of using the LM2596 buck converter and a 24V wall wart, why not use a 5V wall wart? Switching regulators are relatively efficient compared to linear converters, but 24V for 5V is a big drop and you’ll get efficiency well under its best-case efficiency (~80%).

Anyway, if you didn’t care about power conversion efficiency, it’s still more expensive to buy a bunch of LM2596 modules than buying a simple 5V power supply.

A 5V wall wart can supply 5V to as many devices as you want, as long the current draw from all the devices doesn’t exceed the current rating on the power supply. For example, this is ~$5 and will give you 2 Amps (just the first result I found, you might want to shop around):
http://www.amazon.com/2000mA-Regulated-Power-Supply-1-35mm/dp/B005CVNH1Q/ref=sr_1_1?ie=UTF8&qid=1427683870&sr=8-1&keywords=5v+dc+power+supply

Then you can supply 5V directly from the power supply’s 5V output to the Arduino’s “5V” pin, and from the power supply’s 5V output to all your other 5V devices. Does that make sense to you?

It depends on what the devices are and if they are connected to the Arduino. If they are sensors or very low power, then run them off the Arduino's 5v pin. If they are connected to the Arduino (motors, servos etc) then power everything from one high-current 5v supply.

ainbritain: Then you can supply 5V directly from the power supply's 5V output to the Arduino's "5V" pin, and from the power supply's 5V output to all your other 5V devices. Does that make sense to you?

That's what I had in mind to do but I wasn't sure if I could input voltage through the 5v pin of the arduino. I thought it was for 5v out only. I have a 5vdc 2amp wall wart laying here ready to use, but I didn't want to smoke my arduino with trial by fire.

I do have a few 12v solenoids that I would like to power through relays of course. I'd like to use just one power supply. If I use a 12v wall wart and then stepped the voltage down with one of the above LM's, would that be the best way??

dpslusser: I do have a few 12v solenoids that I would like to power through relays of course. I'd like to use just one power supply. If I use a 12v wall wart and then stepped the voltage down with one of the above LM's, would that be the best way??

That's the best way I can think of! What is your project?

SCADA system for my house :grinning:

I started with an Uno with a Ethernet shield posting Temp and humidity of my basement to xively

Then I added an Ultrasonic Level Sensor to my heating oil tank and posted that to Xively.

I never had it in an enclosure, it just sat in my basement on a breadboard. So I bought an enclosure.

Now, I want to add an LCD I2C 20x4 screen to display values. A moisture sensor on the basement floor controlling a solenoid for my main water supply in case of pipe break, and current transmitters in my breaker panel for monitoring power consumption in the house.

And the list could go on… :stuck_out_tongue_closed_eyes:

p.s. Temperature sensors outdoor, indoor (upstairs) and in refrigerators/freezers, furnace temp and run time. Creat HMI application on PC using OPC server monitoring modbus registers over RS485, and create historical trending.