3 Ways to power an Arduino Board – Do you know them?
First, using the VIN pin using the DC jack and also using the USB cable.. Each method has some quirks and limits that you wan na, be aware of when you start powering your Arduino. Stay: tuned., triumphant, music, Hey if youre interested in programming real stuff make sure to subscribe to our YouTube channel to get the latest videos we release. All right In our discussion here were gon na be using an Arduino UNO as the base example. Much of what we cover can be extended to other common Arduino boards., But in each case, youll need to double check for your specific model. Were gon na, be using the Arduino Uno electrical schematic to inform our discussion. And were gon na, be looking at the power section specifically. Now it seems like theres a lot going on here, but to simplify this discussion. A bit further were gon na, reduce it down to this block diagram.. This is something I can handle a little bit better.. So let me orient you to this little block diagram. Here. Weve got three items on the left: the VIN pin the DC jack and the USB.. So when you see USB port there, just imagine thats, where your USB cable plugs in. For the DC jack. Imagine thats where you would plug in your DC jack right And for the VIN pin thats just that hole marked on the Arduino power rail where it says VIN.. So if you stick something in there, that is where it would connect up in this schematic.
. Now, on the right side, we have the five volt and the 3.3 volt power pins on the Arduino power rail. In the middle of this schematic, weve got some components that well be talking about here, shortly. All right, so, hopefully, youre kind of oriented with this block Diagram. So lets start our discussion talking about powering with the DC jack. Lets say you hook up a wall, wart power supply or a battery pack to that DC jack. What happens? Well, it powers the five volt regulator on the board., So whats so special about five volts. What do we need a five volt regulator for Well that five volts is right in the range of what the micro controllers on the Arduino board need to operate.. The five volt regulator requires a minimum input of 6.2 volts and can take a maximum input voltage of 20 volts.. So the power supply that youre gon na hook up into your DC jack needs to at least be in that range for the voltage.. The sweet spot is more like seven to 12 volts.. If your power supply is much higher than that, then you end up wasting a lot of power on that five volt regulator in the form of heat dissipation.. Now the DC jack itself, physically its a 2.1 millimeter center positive plug. And its important that the plug you use is center positive, but just in case you accidentally use a center negative plug and accidentally reverse the polarity.
The circuit has a diode that protects against it.. Now thats pretty handy.. I think that diode is probably for people like me who just like to randomly take power supplies and be like quotHey. Maybe this will work.quot One more thing about that five volt regulator. It can provide up to one amp of current. Whats. The big deal about current Well heres, the deal. All the electronic stuff that you attach to your Arduino board, is going to consume current. Its gon na draw current.. In fact, the components on the Arduino UNO itself will be using around 25 milliamps of current.. So if you go attaching a bunch of stuff to your five volt power rail, that draws a bunch of current like say, servos that are gon na be under a high load, then youll be drawing more current than what the regulator is actually rated for.. And what that means is youll burn up the part, something which generally you want to avoid., So that one amp limit is something you wan na keep in mind. Notice that the five volt regulated power supply is what is feeding in to the 3.3 volt regulator.. So youve got your power supply at your DC jack that it could be anywhere from whatd. We say Seven to 20 volts right. It gets regulated down to five volts and then that five volts is what is going to power. Your 3.3 volt regulator, which will then output a regulated 3.
3 volts, which you can access at that 3.3 volt pin on the Arduino power, rail. Thats kind of cool.. Do you need a printed circuit board design software to move your prototype to the next level? Altium Designer is a great choice for designing PCBs, sharing or design with team members and even getting your design manufactured.. What really kind of blows me away about this software is that, even though its a super powerful tool, at the same time, its really intuitive to use. Theyve got helpful video tutorials built right into the software, so you can kickstart your learning process and actually get something. Made. Right now, you can get a free trial to Altium Designer, with our link in the description. Thats right. You can test drive this super powerful software with a free trial., Just check out the link in the description. Okay. So now lets shift to using the VIN pin. The VIN pin on the Arduino power. Rail is where you can hook a power supply line right into the board.. The voltage requirement is the same as with the DC jack, because youll notice VIN is supplying power to the five volt regulator as well.. In fact, powering with the VIN is almost exactly like powering with the DC jack.. But what you dont have on the VIN pin is any reverse polarity protection, because theres no diode protection there.. So you wan na make sure that youve connected positive voltage to that pin.
. Okay, one last thing I wan na talk about as it relates to VIN and using the DC jack. Notice that weve got this dotted connection between the DC jack and the VIN circuitry to what weve drawn out as a switch.. That switch is actually a P channel. Mosfet, which you can kind of think of as like a electric switch, either being open, where no current can flow or being closed when current is able to flow.. If the voltage above that switch is greater than 6.6 volts, then that switch is open. And when that switch is open, what it does is shut the power supply line from the USB cable.. Now there are a lot of details that Im going over rather quickly. Here. Were actually building an entire course at Programming Electronics Academy about how to power your Adruino, how to think about powering your Arduino project and the current inventory and all that type of stuff.. So if thats, something you wan na, learn more about check out the link in the description., So what does this mean? It means that if youre powering using VIN or the DC jack, then the power line from the USB cable is going to be disabled.. It does not mean that the deadlines from the USB will be disabled.. Youll still be able to send information over USB. If youve got it hooked up to your computer and youre doing some development, its just that the USB wont be providing any power to the board.
. So this is a good segue into talking about powering with the USB. Whats cool about USB is that it already provides a regulated five volt supply.. So the circuit skips over that five volt regulator and provides power to the Arduino board and is available to tap into at the five volt pin on the Arduino. Youll notice that it does also power. The 3.3 volt regulator., As far as current goes USB, can provide 500 milliamps for USB one and two and 900 milliamps for USB three.. Now Ive already mentioned that drawing more current than your components are rated for can cause damage to your Arduino aboard.. But what happens when you draw more current than your USB port can provide Well heres whats kind of neat about the Arduino USB power circuit. Lets say you draw more than 500 milliamps of current.. There is a thermal polyfuse in series with the USB port that will get tripped. When that fuse get tripped. It opens up the circuit until that polyfuse resets. Its there to protect your USB port. In case you accidentally overdraw current, which seems to me like a pretty good feature.. Ideally you wont be doing that in the first place, but hey stuff, happens., All right, that was a ton of stuff talking about VIN DC jack, USB port lots of stuff going on.. If youre into this kind of stuff – and you wan na, learn how to code real things that move and do stuff check out the Programming, Electronics Academy membership program in the description below.
. Also, if youre just getting into this Arduino thing – and you need to get your hands on some of the hardware check out the description for some links. Make sure to subscribe to our channel hit the bell to get updates when we drop new videos.. Finally, are you wondering about this picture here at the end, If you send us a photo of yourself working on an Arduino project to benchprogrammingelectronics.com, you might just see a rendition of you and your workspace right. Here. Thanks a ton and have a great one. Bye.
