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I have situation where i need to capture wiegand26 signal. I use it on single twisted pair. But i get a lot of AC noise in UTP cable Cat 6. Shield is not connected anywhere. The VCC for is from wall AC/DC adapter 12V/1000mA. My tester battery is low so it shows 20V with no load... I guess batteries, but i will check again and change it ASAP :)

I added also 10k ohm resistor to pull signal to ground, but it doesn't. The lines in idle is (or should be) +5V. On data transmit it should be 0V.

This is the setup

Edited: Added supply. enter image description here

at the Arduino side i get this

enter image description here

I need to lower the trigger level and i would like to ask if this setup would work. As i understand it should trigger at about ~2.5V? enter image description here

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  • \$\begingroup\$ adding a comparator won't help you here, you need to try to address the issue. I've designed Wiegand receivers but never had to reach 200m before. I'm currently suspecting a power supply issue on the reader side. Where is the supply for the reader in relation to the reader? \$\endgroup\$ – akohlsmith Aug 4 '15 at 18:45
  • \$\begingroup\$ Reader you mean sender? Supply is near Arduino, so it goes by 2 pairs (+,-) and one pair (D0,D1) goes back to Arduino. I don't know how they lay in the ground, so i can be not correct about the length. it can be 100m+. The supply is problematic i guess. i should change it... Tomorow i will \$\endgroup\$ – Martynas Aug 4 '15 at 19:00
  • \$\begingroup\$ and also why it doesnt pull the signal to gnd? \$\endgroup\$ – Martynas Aug 4 '15 at 19:02
  • \$\begingroup\$ Try putting a local power supply at the sender. make the grounds common just as you have now, but you want to power the arduino locally (power supply near the arduino) and a second supply at the sender. I'm suspecting that the voltage at the sender is inadequate, or perhaps the cable resistance isn't allowing enough current through. Let's tackle the easy problems first. Also, if you bring the sender very close to the arduino (for a test) does it work? \$\endgroup\$ – akohlsmith Aug 4 '15 at 19:28
  • \$\begingroup\$ Yes i should eliminate problems one by one, but its sometimes hard to think... 1.5h of sleep today :)) I will try to troubleshoot tomorrow. \$\endgroup\$ – Martynas Aug 4 '15 at 20:26

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