Can I ask somebody to sanity check my wiring before i potentially fry my rather expensive board 
I feel it’s correct (using the hookup guide as reference) and double checked, but a fresh set of eyes surely can’t be wrong!
Everything is supposed to be powered by an external power supply (5v 2A) by adding in the power supply to the breadboard line.
On the mega side 5v from external power goes to 5V pin. 3,3 V pin goes to low side of level shifter.
Pin 10 & 11 is serial pins (I’ve used this before for software serial in another project). Both of them goes to the high side of the level shifter on a channel each.
On the level shifter we have 5v from power supply to high side and the 3,3 from the mega mentioned above.
On the M7E side 5v from power supply goes to VCC pin.
TXO and RXI pins are going to low side of level shifter.
Everything is connected with common ground.
From what I can see, it looks correct.
1 Like
Nothing went up in smoke, so that’s the good thing 
The module is scanning (or at least that’s what it is printing in the serial monitor), but it fails to pick up anything from the external antenna. If I switch to usb mode (unplugging from the arduino) is works perfectly fine.
Could the failed scan in the arduino be caused by the low read power - even it the tag is virtually laying on top of the antenna?
don’t set it too low, but it should work on 5dbM.
For test, remove an RX or TX wire to make sure it detects the M7E correctly. ( With the removed wire it should give an error message of course)
Also try moving and turning the tag slowly across the antenna.
If i remove the rx and tx wire (or even just switch the pins in the code) it does throw the error message as expected.
It doesn’t matter how I turn the tag around on the antenna, it’s rather strange really - unless I’ve messed up the pins somehow 
Alright I hooked up the external power supply to everything and then it started to scan it perfectly fine. I guess the power delivered from the 5V Mega from the USB wasn’t sufficient to make reading work correctly!
The u.FL connection for the antenna looks a bit caddywompus as well, you might re-seat that (in the photo it looks tilted/a bit high…might just be an optical illusion from the lens taking the photo, as the board looks curved too lol)
Yeah it does seem a bit odd, perhaps the tape is pushing a bit too much down. It reads fantastic though, il really surprised how far it reads even with just 500 power 
