A 3.3 volt supply generated by the on-board regulator. Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). This pin outputs a regulated 5V from the regulator on the board. You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin. The input voltage to the board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). If using more than 12V, the voltage regulator may overheat and damage the board. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may become unstable. The board can operate on an external supply of 6 to 20 volts. Leads from a battery can be inserted in the GND and Vin pin headers of the POWER connector. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. The power source is selected automatically.Įxternal (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The Mega 2560 can be powered via the USB connection or with an external power supply. You could of course use a DC-DC step down / Buck Converter to take 12V to some lower voltage outside the board. Why is the Vin pin not supplying 12V? Do I need to put an extraneous transistor in that as well? I don't see how limiting the current the Arduino supplies changes the voltage it's supposed to output.The MEGA does support 12V DC input in the Jack - a big chunk of the power will get dissipated by the regulator as the MEGA converts down to 5V so that might have some unwanted heating effect depending on what you need to power through the board. Why is the Arduino trying to fry itself by supplying more current to the device than it's supposed to? What kind of transistor are you telling me to buy - 12V 40 mA and 5 V mA? I am literally following setup guides that show this exact same wiring diagram and code. Modulating voltage should modulate the speed (and therefore volume of air) of the fan? The tiny fan I'm using has 3 pins, one of which is just a useless signal pin that just notifies a computer that it's working - the third pin (signal) on the fan is not connected to anything. It's not a 12V fan, it's a single 5V fan? If you got a computer fan with PWM speed control (the 4-pin ones) the extra pin is for PWM speed control, and you can put 12v across the fan and use 5v PWM on the PWM speed control pin, and then you don't need additional components. If you used an N-channel MOSFET on the low side of the fan, and put the high side onto +12v, you could run the fan at a full 12v (I don't think all of those fans will even spin at 5v) You need to use a transistor to switch high current loads. Stop doing that before you burn out the pin driver. Oh yeah, there's no way you can power a 12v fan that typically uses that type of connector via an Arduino I/O pin, even with 5v, it would draw far too much current (which is what is happening, that's why the pin isn't able to provide a whole 5v). put your main code here, to run repeatedly:ĪnalogWrite(fan1Pin, 250) //Should be linear relation between 0-5V and 0-255 analog output.Ĭorrection: Vin is only supplying 4V when it's supposed to be supplying 12V. put your setup code here, to run once: This pin is PWM enabled for analog output 0-255 Sketch: const int fan1Pin = 5 //Output pin for the fan. It measures 3.23V for DC and square wave is just -000. I am placing it at the exposed yellow wire and the black wire at the base of the fan. I'm using a multimeter set to measure DC voltage and the square wave. Pin 5 (on the PWM side) is an output going to the red (+) terminal on the fan, black (-) terminal is hooked up to breadboard bar wired to the arduino's ground. There's a 12V power supply to the board in addition to USB. Need to see your wiring diagram - have you other stuff connected ? How are you measuring the voltage ? And your sketch - something is wrong but it’s not obviousĪttached picture of wiring setup.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |