For a university project, I got an M6E Nano Simultaneous UHF RFID reader and an original Arduino Uno R3 (which seems to have the same AC socket as the SparkFun RedBoard Qwiic?). I would like to improve the read power by - like in the documentation https://learn.sparkfun.com/tutorials/si … iderations recommended - hooking the Arduino up with an external power source (5V 2A wall adapter by LEICKE). However, the Arduino board, just like the RedBoard, seems to only support 7-12V input through this socket.
What is that part of the documentation about? Did I misunderstand something? The documentation shows exactly the setup I have. Is it still okay to use the 5V 2A wall adapter or will that break something? I am obviously terrified of destroying brand-new equipment on top of being quite new to the world of micro-controllers, so I would really appreciate some input here. Thanks in advance!
It should be fine; the main issue of concern is the voltage drop the from the barrel across the voltage regulator…supplying 5v barrel outputs 4.1v to the 5v pins on my Redboard…the good news is the m6e can use 3.7-5.5v https://cdn.sparkfun.com/datasheets/Sen … Reader.pdf
So…5v 2a barrel supply should be fine, you might get brown-out trying to read at full power (27dBm) but I’d guess even that works fine
Side note: underpowering usually results in things simply not turning on, overpowering is the scarier way to err because things become BBQ 
The question/issue about the power supply to the M6E has been handled already several times.
There is a “bit” more to it than the answer from TS-Russell, although he is mostly right.
Connecting a stronger power supply to the UNO R3, does not help. The UNO-R3 onboard power logic (including diode) and printpath can only handle 1A. The only way that works is by connecting to the M6E external connector a power supply that delivers between 3.7 and 5.5V. As you do that you need to cut JP1 on the back to disconnect the 5V from the USB connector
The power supply needs to be strong in handling bursts. The M6E is VERY sensitive to that. So look for a power supply with good capacitors, not a wall wart. From the M6E hardware book :
Power consumption may increase, up to 8.2W, during operation into return losses worse than 17dB and high ambient temperatures. This is with 5V supply.
You could also start by connecting a charged 3.7V LIPO. (the LIPO will NOT get charged by the board only discharged).
When running on 27dBM the M6E will get hot very quickly. So you need to consider a good cooling block. If not the M6E will bail out quickly at about 70C. Normally it will restore itself when cooled down.
With 27dBM you should use an external antenna. You will not get a lot of benefit with the on-board antenna
Last point: search in the forum viewforum.php?f=118. Many postings that can help u.