Multiple RFID readers, external power supply issue

Projects General Guidance
1

Hi Arduino forum :slight_smile:

Im doing a project where I need 9 RFID readers connected to the same arduino.
Im aware of the communication and listening for one reader at a time, using SoftwareSerial for this.

The issue at the moment is the arduino cannot seem to power up even two readers, it loses USB connection.
So I decided to use an external power supply only for the readers, 9v DC capable of 1.4a.
I use a regulator for 5v to yeah, regulate the voltage :cold_sweat:

The first reader works smooth with the external power supply and reads at a perfect distance etc.
My problem is when I connect the second one, they both work. But the distance they both read is discreased immensely. I assume this is because of the power consumption and an error in the setup. How can I get the same distance for all readers as I have for 1 ?

NB: Im new to arduino and electronics, ill try to keep up :slight_smile:

The attached image shows the setup for two readers. Hope it makes sense :roll_eyes:

RFID reader ID12 datasheet: http://www.id-innovations.com/httpdocs/EM%20moudule%20SERIES%202007-10-9_wfinal%20v22.pdf

2

My problem is when I connect the second one, they both work. But the distance they both read is discreased immensely. I assume this is because of the power consumption and an error in the setup.

Yes they will. RFID readers generate a field and unless the readers are 2 meters apart or more then these fields will interfere with each other.
It's physics, nothing you can do, and it is not the power supply.

3

Grumpy_Mike:
Yes they will. RFID readers generate a field and unless the readers are 2 meters apart or more then these fields will interfere with each other.
It's physics, nothing you can do, and it is not the power supply.

Makes sense :cold_sweat:

Do you know if I connect more readers, if the distance will reduce even more ?