Hi geeks,
I have 2 rfid readers, one can read tag to 3 centimeters and one only 0.5 cm.
I look than the pcb are the same, but 3 capacitors are not the same.
Can i have the value from the polarised capacitor C8, C12 and C20.
Regards.
Check C2 and R1 mainly. C2 should be 22nF. R1 should be 22R.
Yet, mainly focus on the power supply. As mentioned at the bottom of its page:
The USB cables and ports affect the read distance of MOD-RFID125. The board has no input voltage regulator and the main chip is powered by 5V taken directly from the USB. Furthermore, the board consumes considerable amount of current, around 150mA and sometimes even slightly more. Consider that:
- some low quality cables use wires made from materials with very higher inner resistance which also drops the voltage; some other cables are simply too long and also drop the voltage
- after some USB hubs this 5V voltage might drop significantly, because low quality materials with high inner resistance were used which means that the current consumption raises
- some USB ports simply do not meet the USB standards
- consider using USB-CAP between the reader and the USB port that would help sudden current surages