Powering issue at 5v on the Simultaneous RFID Tag Reader

Hi,

I am having trouble with finding the correct powering for the board.

In the guide it says its best to power the board externally with 5v.

But when i do that the reader can’t find any tags.

When i hook it up at 3.7v then the reader works without any problem.

I find it verry strange that on the higher 5v the board does not seem to scan anymore and on a lower voltage it does, but when you go to 3.3v then the power is not sufficient for the board.

But the problem is more that most boards have 3.3v or 5v pins. So in not 1 case this works for me.

Allthough i also power the bord with 5v at 3amp.

The only way i see the board working with 5v and no problems, is if you hook it up at the USB to SERIAL and view the scans in the software application.

I also cut the JP1 jumper like mentioned in the tutorial.

The board is now running at a gain of nano.setReadPower(2000); and it’s running on 3.7v which then has no issues.

Thanks for the help!

What is the current rating on the 5 volt power supply you’re using? From your symptoms it sounds like your 5 volt supply is not able to provide the needed amount of current.

YellowDog:
What is the current rating on the 5 volt power supply you’re using? From your symptoms it sounds like your 5 volt supply is not able to provide the needed amount of current.

Hi,

The power supply i am using is 5v and 3A.

This should be more than sufficient, because I measured peaks of just over 1A with the RFID reader.

The problem you describe is very well known. It happened a lot to me and as YellowDog described the root cause is the power supply. The issue with the power supply is not 1A… it is peak loads in very short moments/spikes. When you connect a 3V7 LIPO it will have enough capacity to keep 3v7 for those peakloads as it tries to read the tags. You can try to add extra strong capacitors to handle those peak spikes.

paulvha:
The problem you describe is very well known. It happened a lot to me and as YellowDog described the root cause is the power supply. The issue with the power supply is not 1A… it is peak loads in very short moments/spikes. When you connect a 3V7 LIPO it will have enough capacity to keep 3v7 for those peakloads as it tries to read the tags. You can try to add extra strong capacitors to handle those peak spikes.

Hi Paul,

Thank you for the verry clear explenation!

With a Lipo battery attached it indeed works!

What type of capacitors should be sufficient for handling the spikes?

Best Regards,

janhemelaers:

paulvha:
The problem you describe is very well known. It happened a lot to me and as YellowDog described the root cause is the power supply. The issue with the power supply is not 1A… it is peak loads in very short moments/spikes. When you connect a 3V7 LIPO it will have enough capacity to keep 3v7 for those peakloads as it tries to read the tags. You can try to add extra strong capacitors to handle those peak spikes.

Hi Paul,

Thank you for the verry clear explenation!

With a Lipo battery attached it indeed works!

What type of capacitors should be sufficient for handling the spikes?

Best Regards,

Unfortunately it was short lived and I think it was just luck. After restarting the RFID reader it is still the same problem. If I provide exactly 3.7 volts with the Nordic power profiler, the reader works. in other cases still not.

Weird…

what reading power to do you apply ?

is the M6E getting hot ?

is the LIPO you use fully charged ?

Did you cut JP1 when you connect an external power supply ?

As for the capacitor, take one that has very low internal resistance. There a number of articles on internet about that focussed on fast discharge/enery power. e.g. https://capacitorsuper.com/supercapacit … esistance/, https://www.edaboard.com/threads/how-to … or.141111/