Hall Effect Sensor and gain circuit

Hall effect sensor with op-amp gain circuit( 70 - 100X) to facilitate DC and DCC current detection

Schematic

Arduino

Because we have a DCC/DC mixed environment, we need a micro-controller to monitor track voltage and when voltage drops below a set threshold, occupancy status will be latched. The controller will latch the "busy" signal for a set amount of time, or when voltage is above a threshold value to return to normal operation.I designed our own block detectors as an inexpensive alternative to purchasing remade modules.

PCB Build

Image Added

(Still waiting for J4 screw terminals to arrive - this is what connects back to the CMRI node)

Image Added

Quick and dirty, but using the same current transformer that the NCE version uses (1:200 turn ratio)

• LED1 electrically does not have a polarity as it voltage is AC and swings positive and negative

Wiring

Install on the red wire side of the feeder.

20 Jul 2022 TODO: Add example of installed detector.

Demonstration

This video demonstrates over-current  and reset using a 2A high current short in parallel with a 200mA load across the track. Over-current LED comes on and resets with 200mA load on the track after the short is removed.

BOM

Single wire through current transformer is xx" long