i have a RFID reader that has 4 outputs and each one puts out 5v and 16ma max. i want to have the arduino turn on an led when the reader sends a signal to the arduino but i am worried that the arduino will pull more than 16ma and fry the output (this has happened) so my question is will the arduino pull to much current from the reader
Do you have a link to the RFID reader in question? Typically, if it says it supplies 16mA max, it means that it has some limiting mechanism is place. However, if you want to light an LED using that 16mA of current, you should choose an appropriately sized current limiting resistor, based on the voltage drop of the LED you are using.
On the other hand, if the output from the RFID reader is simply a signal, and the Arduino reads that signal, and triggers another pin to light an LED, the Arduino will draw very little current (the pins are high impedance pins, which means they are high resistance, which means low current).
i thought the reader would have something to limit it too but if something draws to much current it frys the output to where you cant turn it on or off anymore
it will be 6 LEDS to each reader output
i have a RFID reader that has 4 outputs and each one puts out 5v and 16ma max. i want to have the arduino turn on an led when the reader sends a signal to the arduino but i am worried that the arduino will pull more than 16ma and fry the output (this has happened) so my question is will the arduino pull to much current from the reader
You have a little misconception about Arduino I/O pins. When a Arduino pin is set to be a digital input pin it draws almost no current at all as it's a very high input impedeance, so no problem wiring them to digital outputs from your device.
When a Arduino I/O pin is programmed to be a output pin, then that is where you need to be concerned about how much current any external devices tries to draw from the Arduino output pin. 40 ma is absolute maximum, but 20-30ma is the recommended max.
Lefty
I'll repeat myself.
Do you have a link to the RFID reader in question?
What is the reader outputting? Typically, they output serial data. Why would be attaching 6 LEDs to each output?
basically this whole setup is for meetings or conventions that have many people, that have to get to specific meetings. so i am making an led light stack red, green, and yellow, that will tell a person with a specified tag to their name whether they are going to the right meeting or not
red (error)
green (correct meeting)
yellow ( wrong meeting)
the reader uses a 15 pin gpio for signals/inputs
i do not know what type of data it puts out
Is this RFID reader some top secret device? If it is, you're on your own interfacing it with an Arduino.
If not, post a link.
http://www.buyspeedwayrevolution.com/
that is the reader
that is the data sheet for the reader page 35 is the gpio data sheet