I am a novice user of Arduino. I am not sure whether I can connect both USB and external supply through power adaptor to Arduino simultaneously. Would this burn the controller?
Lets study the schematic of Arduino UNO R3
The input from the power supply plug (PWRIN, the power jack) goes through a diode D1 (to prevent reverse polarity), and feeds a NCP1117 ...
The datasheet shows that current decreases at lower frequencies. Around 1 mA at 1 MHz running at 5 V. More like 5 mA at 8 MHz running at 5 V.
You can save quite a bit by using lower voltages as well, as you can see. For really big savings use a sleep mode. Read about Power saving techniques for microprocessors.
(Edited to add)
To amplify on my remarks, ...
The design assumes USB provides a regulated 5v so no further regulation is necessary. The power connecter is meant to accept a wider range of voltage and regulate it to 5v, and the kind of regulators used on the Arduino board need that much higher voltage to provide regulation. If you already have a regulated +5v source you can supply it to the 5v pin. You'...
Note: I wanted to point out that, even though my answer was accepted, the reader (you) should really read Anindo's answer first if you really want to save energy with any Arduino board. Once you address those items in your design, then you should read my answer and worry about how to set the MCU into low power mode.
Having said that, there are several ...
Realistically, the biggest power waster on an Arduino board is the linear voltage regulator on it.
As long as the microcontroller on the board, the LEDs, or any other peripherals, draw current, the linear regulator wastes power equal to difference between supply and board voltage x current drawn.
So, a first fix would be to disconnect the power indicator ...
The Arduino boards use a fair bit of power compared to other embedded systems with similar functionality.
There are three main factors:
The NCP1117 (datasheet) 5V linear regulator in the Arduino UNO
R3 (schematic) has a quiescent current of around 6mA.
The ATMega328P (datasheet) draws around 5mA @ 8MHz and 5V, and probably more than ...
Use a switching regulator such as the LM2596. You can get a ready board from eBay for about US$1.
Just set the output voltage to 5 V and feed the Vcc input of Arduino; this bypasses the onboard regulator.
The benefit is that unlike the linear onboard regulator, a switching regulator is very efficient which means less consumption and less generated ...
I made up a small torch locator which used an ATtiny85 powered from a button-cell (CR2032). It looks like this:
That currently weighs 5.9g. The battery-holder weighs 1.6g so you could save that by making a more light-weight holder (perhaps a bit of plastic for insulation, and soldering directly to the battery). The chip socket weighs at least 0....
The best way of doing this, if you want your USB connection to still work, is to remove the P-channel MOSFET T1 from the board.
You can't just disconnect the power from the USB port since that power connection goes directly to UVCC on the ATMega16U2 chip. That is used to power the internal USB peripheral (it goes to a 3.3V regulator inside the chip) and ...
You could read through the 200-page datasheet, and then mess with some confusing bit shifts and registers, but I recommend this library: http://playground.arduino.cc/Code/Enerlib
Also, if you're using an Uno or any one with a usb-to-serial chip, you could disable that or remove it.
A 555 doesn't have to generate a 50% duty cycle. Even if you do want to use a 50% duty cycle, the edge can be RC coupled into the interrupt to reduce the pulse width.
An Arduino can use a slow clock like a 32kHz watch crystal, then it's very low power indeed. This slow one can be used to wake-up your more power-hungry Arduino.
The lowest power and tidiest ...
The Arduino Uno can be powered via the USB connection or with an external power supply. The power source is selected automatically.
Put the external power through a voltage divider or transistor-based inverter and into an analog (divider) or digital (inverter) pin and check the appropriate value from the pin. Note that ...
Well, it depends on what you have attached to the Arduino. If you are using the pins to do things you will definitely require more current.
If you are only want to ONLY power the Arduino, then I calculated what I think it should be below. (You should also check with someone who owns this device for an experimental value, and not just a calculated value. )
Actually, Arduino is powered at 5V (the 5V pin and the ATmega328p are connected to the +5V rail in the board). The point here is where do those 5V come from. Basically, from 2 possible sources:
USB. The 5V line from USB is (or should be) already regulated, so it's feed directly (in fact it goes through a polyfuse) into the +5V rail of the board. The maximum ...
If you power the Arduino with an external power supply the on board regulator has to dissipate the voltage difference between input and 5VDC at the total current you draw from the board.
As Klaus Warzecha wrote in an answer to another question
The Arduino is just the brain, not the power station.
If the output voltage of your power supply is 12V, then ...
Nowadays, most smartphones come with a charger that is linked to the USB plug of the phone.
The charger for my HTC says: 5V, 1A, I guess this voltage must be regulated (but I haven't checked it has the charger is sealed).
The charger itself has a female USB socket on which you can plug any USB cord to link to your Arduino.
IMPORTANT! I have never tried it ...
The link you provide looks rather old and I don't think it applies to UNO Revision 3 as it has more pins than on the diagram you show.
I suggest you rather take a look at this Arduino UNO link which contains uptodate information about the UNO; in there you will see that for R3, the "power rail" has been extended and has the following pins, left to right:
Yes you can. It still leaves the data/ground lines intact, it just doesn't bridge the 5V line.
Arduino Uno Schematic v.3:
The USBVCC is directly from the 5V on the USB jack (well, technically there's a fuse there). It then goes through a transistor (T1) that only allows power through when there is no power coming from the 5V regulator (that regulates the ...
The problem is most likely that the system is going to sleep while it's still sending the serial data.
Forcing all the serial data to be sent before you go to sleep should fix the problem (serial data is sent in the background using an interrupt so as to keep sketch slowdown to a minimum):
LowPower.powerDown(SLEEP_1S, ADC_OFF, BOD_OFF);
The best solution for you is to use LowPower library which does not require any external parts. It supports up to 8 seconds sleep. If you need exactly 10 seconds you can write a loop with 5 cycles and call powerDown with 2 seconds sleep.
If you still want to use external interrupt, see this for some chip options.
Also, see this article for some good ideas ...
There are three power supply pins on the Arduino Uno and on the Mega:
5V - Labelled as 5V. Can be used to power other 5V devices.
3.3V - Labelled as 3.3V. Can be used to power other 3.3V devices.
Vin - This also referred to as the 9V pin that is shown in the schematic. This is used to power the Arduino board itself, usually using a 9V battery.
Once your project is working and you need to deploy to "production" environment, you can opt to replace the Arduino with a bare meta ATMega328 or any of the ATTiny family chips. This will get rid of all the power eaters on the Arduino board you don't need.
Arduino board of 9V block battery - 56 mA
ATTiny85 bare on 8 MHz without sleep modes etc - ...
The Arduino doesn't require 5V.
The Atmel chip on the board requires somewhere between 1.8V and 5.5V, the Arduino just happens to have chosen 5V as a good common widely used voltage to run at.
If you provide a voltage within that range to the +5V pin the board will operate. There's a couple of caveats though:
Anything below about 4V will mean the 3.3V ...
Unfortunately there is no one "clear cut" answer for all you ask.
There are some hard limits, though, which you can get from the main chip's datasheet:
Operating Voltage: 1.8 - 5.5V
But that's not the whole story. The minimum voltage depends on the clock speed of the chip, as shown in this graph:
But wait, there's more. The Arduino also contains a 3.3V ...
You are already using a differential signalling system that doesn't care about ground levels, so you don't need to worry about that side of things.
As for power distribution - a strategy known as point of load regulation is what you want. That is where you supply a higher voltage (but lower current) power feed to one, or in this scenario more likely a group ...
In electronics circuits, a major point in connecting two circuits and make them "talk" together is to ensure, at the minimum, that they have a common reference of voltage (typically called GND and defined as 0V voltage).
On Arduino, GND pins can be used in 2 situations:
to directly power the Arduino with an external supply which cannot be plugged to USB or ...
I would personnaly suggest an ATtiny 45/85. It is pretty much a small AVR with 5 GPIOs. You can program it with the Arduino IDE and use the Arduino as ISP. If you can design you own custom PCB, a SMD version of the ATtiny is small, low and compact. The total circuit to make the ATtiny function is also minimal.
Also, at a low clock speed (0-4MHz), you can ...
You decide which rails are positive and which are negative when you connect them to the + an - from your power supply or battery.
A breadboard isn't polarised per se. It's just a bunch of cross-connections inside a perforated plastic case. No active or passive components inside.
Some manufacturers may choose to paint indications regarding where to connect ...