I'm making this Arduino project and I'm at the point that I'm starting to design a PCB. But the problem I'm running in to it how to power everything. I would like to have two options, 1 power with a USB cord, 2 power with a battery. When use the USB I'm stepping up the voltage to 9 volts so the Arduino can run smoother, anyway that's what iv read. But I'm not sure what to do with the battery, should use have two different boost converters on my board from the USB cable and one for the battery, or step down the 5v from the USB to 3.7 volts and them back up to 9 volts. I would like to use the 3.7 volt lithium Ion batteries because they have a decent battery life. Or are there any other options out there. And if i install the battery (which would eb optional on the board) i would like for the USB power to charge to battery.
You can use a SEPIC (Single-Ended Primary Inductor Converter) the output powering the Arduino and you can diode 'OR' the two inputs, the higher voltage will automatically be selected and it will cover the fully discharged voltage of the battery and work with fine with a 9 volt or higher input. Replace the LED and resistor with the SEPIC converter.
I powering the Arduino through the vin. I looked up what the best voltage is to power the Arduino and it said 7-12 volts so i went with 9 volts because it in the happy middle.
#gilshultz I've never heard of a SPEIC Inductor converter. Ill look into it is seams to be a step in the right direction for me.
That is where you are getting confused. The Vin pin on an Arduino Uno sends the power from the internal voltage regulator, which can not produce much current mainly because of thermal issues. The best voltage you can use to power this is 7.5V, this reduces the amount of energy you have to burn off as heat, as well as being able to use the power jack, which has a series diode in the line.
Yah @bradley_waldner_mg , there are probably better ways to do this. I think basically everyone here agrees that powering the Arduino with 5V, through USB or through the 5V pin, is usually better than using the VIN pin.
My suggestion for you is to have one power option which is just connecting to the USB plug on the Arduino, and a second power option which is a lithium battery powering the 5V pin. I've made a few circuits to power an Arduino with a Li+ battery and a boost converter, and they worked great. It's totally doable.
Here's a circuit that I use all the time to power an Arduino on a 3.7V Li+ battery.
The RT9361A (or equivalent) chip works great for boosting the battery voltage to a nice regulated 5V. Notice that I use two of those chips in parallel, because they are only good for ~250mA each. Two of them connected this way provides the 500mA MAX that an Arduino can use in the first place.
I also included a little voltage divider (R1 and R2) to measure the battery voltage directly. You can just do an analogRead on that pin and see if the battery is getting low.
Will you be using one of the regular Arduino boards, and if so, which one, or will you designing your own board? I think some of the new-fangled fancy Arduinos or Adafruit development boards have a built-in battery charger, but I think those are primarily 3.3V devices. Actually, you might consider using a 3.3V Arduino like the Pro Mini if the other devices in your circuit will work at 3.3V, as that might simplify charging and regulation. So can you tell us a bit more about your project?
So reading all these responses. These best way to power the Arduino Nano is just through the USB port. But I would like to power is from a different spot because when using the project in the field i don't want to be able to connect to the Arduino (Ill have to take apart the box that its in to program the Arduino).
So stepping 5 volts to 9 volts is just a waste of time. So i should just use the 5 volts that i have on hand through the 5v pin and the 3.7v Li+ battery when i use to to the 5v pin as well.
I have powered some projects through the Vin pin with a 9volt battery and i have seen any problems yet. Figured that using the Vin pin frees up the 5v pin to power buttons and encoders.
This is my fist PCB project and it will have the Arduino nano integrated. I need a lot of these boards that's why I'm designing a PCB. And in the future I'm thinking of just use a micro chip instead of the Arduino to make the PCB board design smaller. But now i don't really have the time to do that sooo.
That's why i using the Form I'm hear to learn the best way to do things. So your saying i should just use the 5 volt i have on hand to power the Arduino through the 5v pin and power that encoder as well. I don't know i could.
If you have 5V supply and you need 5V for your devices, for sure you don't step it up and down just because arduino has single 5V pin. Just connect the wires of all 5V devices to wires of 5V supply.
Ok that make sense that now makes things easier ill just keep the volts at 5 and then when using a 3.7 volt battery i just have to boots that to 5 volts. And i wont have to fool around with 3 different voltages.
I think we still need to pin down how the battery will be charged - from a USB port on your computer, or from a dumb USB charger wall wart. And there should be something simpler than that video for the boost converter.
If you would be open to adding another module to your circuit, you might look on Youtube for videos on the J5019 module. It is a combination single-cell lithium charger and a boost converter. It could be appropriate if your circuit will be running on battery most of the time, with external power connected only occasionally to charge the battery. It has a microUSB power input port.
