hopefully the pins should not exceed the current draw from the USB power supply because they are only receiving voltage from the pots and buttons.
Quote from: operators123 on Feb 15, 2014, 11:12 am hopefully the pins should not exceed the current draw from the USB power supply because they are only receiving voltage from the pots and buttons.I don't understand what that means.
i cant figure out how exactly you plan to connect the arduino and the leds on your project. but i shold work in general. i did so powering a motor with an extra battery and one battery for the arduino-board.you have to pay attention, that you dont connect the two +5V together!
Couple of observations, then:You need to hook the ground shown to the Arduino ground, else (for example) the output from the pots' wipers will have no meaning. A bit like imagining the sound of one hand clappingDo you mean the LEDs to be on all the time?- if you intend to control them from Arduino there will need to be some switching mechanism like a transistor whose base is connected to an Arduino digital pinYou'll need a resistor on one side of the button as a pull-up or pull-down (or use the internal pull-up via code) else when it's closed you'll short 5v to ground. Have a look at the circuit and sketch here
I left the resistors out the diagram because I was too lazy to add them
Now, the potentiometers are presumably at least 10k each, so even ten of them in parallel would come only to 1k and draw 5 only mA.
The potentiometers are supplied from the 5V Vcc line on the Arduino. This is not only for safety - ensuring that the voltage from the wiper cannot exceed that 5v supply voltage, but also so that the readings are always relative to that voltage and read the same for any given position.
Encoders will probably need to be powered from the Arduino Vcc as well, unless they draw significant current (more than 10 or 20 mA).
Now all that said, if your 5V 3A supply is a switchmode design and fully regulated, preferably with a "crowbar" circuit to shut it down should it fault and exceed 5.6V, then you can use it to feed Vcc on the Arduino. Otherwise, it sounds as if it is primarily for powering the LEDs. If you intend to use the LED strips which do not employ integrated IC drivers, you probably want to use 12V instead. You will require some sort of driver circuit to switch the LEDs from the Arduino.
I thought encoders were not connected to vcc, only GND and two digital inputs (interrupt pins for best performance right?)
My 5v/3a supply is a power cable that's used to power a Cisco device or something like that, it looks like a laptop charger cable I guess, just says 5v/3a on the box.Feeding it to Arduino is something I considered, (through VIN and GND pins) I was just unsure as to whether this would damage the atmega2560's pins if I'm drawing about 1A from the power supply, or whether Arduino would regulate this down to 500ma.
I must point out the fact that because the LED's are on the same PCBs as the pots and buttons, this means that I want to only have 1 vcc and 1 gnd rail for each pcb. (having two would get too complicated)