Hi, I'm making a rover-like device which will eventually use 4 of the 9g servo motors, one 28by-j48 stepper motor, and one ultrasonic sensor.
At the moment, I only have one servo, stepper, and ultrasonic hooked up through the arduino's 5V outlet and it runs fine. But, I'm assuming adding the other 3 servos will make the current draw too high if it isn't already.
Right now the Arduino is powered from a USB power bank with output of 5V 1.5A and capacity of 3000mah.
Questions:
What are my options for powering this mobile rover? especially when the other 3 servos are added.
Do I need a second power bank (one for the Arduino, and one for motors) or can I run a single power bank into some kind of power distributer.
Also, is 5V too low for the power supply? And do I need something more like 9V?
I've attached a picture of the only power distributer I have.
Basically, what are my options and what do you recommend?
I would advice against powering any type of motor through the Arduino regulator. Figure out what will be max current you'll be drawing. Is it below the powerbanks 1.5A? Great! Not? Might need to add more LiPo's.
What kind of Arduino board are you using? I will assume Nano, Uno or Mega. You can run the arduino on 5V perfectly fine, but not through the Vin pin (that requires 7V min). Instead, supply directly to the 5V pin. Do this ONLY if you're 100% sure your supply is 5V. I'd also recommend going through a diode for protection.
Also, those little breadboard power supplies are usually unfit for anything drawing more than a few 10s of mA, in my experience.
therazer009:
Is there a benefit to supplying the power through the 5V pin on the Arduino vs using the USB input or the dc jack?
The Arduino will not work, or at least not reliably when supplying 5V to the DC jack or the Vin pin. Due to the voltage drop across the regulator, at least 7V or preferably 9V is required.
Ah okay. Is there a good way to distribute the power into jumper cables for the Arduino and motors? The power bank I'm using only has a USB output, so how can I distribute power between all of the devices+ the adruino? I checked and the current should be more than enough for my purposes.
therazer009:
Ah okay. Is there a good way to distribute the power into jumper cables for the Arduino and motors? The power bank I'm using only has a USB output, so how can I distribute power between all of the devices+ the adruino? I checked and the current should be more than enough for my purposes.
Thanks for the help!
The most straightforward way? Get yourself a soldering iron!
So cut open the other end of the USB cable and wire it in? Should I use a capacitor to ensure the voltage or would that cause a voltage drop? Is the diode just for ensuring the correct direction of voltage flow?
In my experience, no cap is needed with power banks. I would put a diode (something like a 1N4148) between the supply and the Arduino's 5V pin. That way, you don't blow up your arduino if you connect its onboard usb without connecting the powerbank.
Another question, I looked up the 1N4148 and it says its maximum forward carrying capacity is 300mA. I have some 1N4007 diodes which have a max of 1A. Isn't this too small for the power bank which has 1.5 A? I know the current is going to be split many ways between the Arduino, motors, sensors, etc. But, eventually, I may use a power bank that delivers around 2.5A. I suppose the 1N4007 would still be plenty fine for this, but won't the voltage drop from the diode be too much, or is the Arduino okay taking something like 4.1V through its 5V pin?
The problem was that I don't want too much current draw from my Arduino when I add more motors later. Everything was being powered straight through the Arduino. I don't have much of any electrical experience though so most of the things I'm saying are based on what I've heard or read.
therazer009:
Another question, I looked up the 1N4148 and it says its maximum forward carrying capacity is 300mA. I have some 1N4007 diodes which have a max of 1A. Isn't this too small for the power bank which has 1.5 A? I know the current is going to be split many ways between the Arduino, motors, sensors, etc. But, eventually, I may use a power bank that delivers around 2.5A. I suppose the 1N4007 would still be plenty fine for this, but won't the voltage drop from the diode be too much, or is the Arduino okay taking something like 4.1V through its 5V pin?
If you put the diode between the powerbank and the arduino, and connect all motors directly to the powerbank, the diode will only see the current drawn by that Arduino itself. So no problem using a 1N4148!
therazer009:
The problem was that I don't want too much current draw from my Arduino when I add more motors later. Everything was being powered straight through the Arduino. I don't have much of any electrical experience though so most of the things I'm saying are based on what I've heard or read.
You might look at an electrical schematic for your arduino. Been a long time since I looked at one, but there was somewhat of a power auctioneering setup where the arduino got its power from the line in thru a regulating chip, or directly from the USB connection, with the preference being the USB source.
TimMJN:
If you put the diode between the powerbank and the arduino, and connect all motors directly to the powerbank, the diode will only see the current drawn by that Arduino itself. So no problem using a 1N4148!
Okay, but there won't be any noticeable amount of voltage drop across the diode using 1N4148? I thought if I'm supplying power through the 5V pin that it has to be pretty much exactly 5V, but maybe a little less is okay too as long as it's not more than 5V?
zoomkat:
You might look at an electrical schematic for your arduino. Been a long time since I looked at one, but there was somewhat of a power auctioneering setup where the arduino got its power from the line in thru a regulating chip, or directly from the USB connection, with the preference being the USB source.
I think if I'm supplying power into the Arduino through either the USB, DC jack, or Vin slot, there will be some amount of voltage drop due to regulators and whatnot. So, I was going to power into the 5V slot which doesn't have a regulator so I can directly power the board with no voltage drop since my power source is only 5V to begin with.
therazer009:
Okay, but there won't be any noticeable amount of voltage drop across the diode using 1N4148? I thought if I'm supplying power through the 5V pin that it has to be pretty much exactly 5V, but maybe a little less is okay too as long as it's not more than 5V?
I've powered arduino's from powerbanks like this a few times, never had any problems!
