Reed Switches, non powered for direct connection to a Feedback Module.
Data sheet for Littlefuse Reed Switches
Protected Reed Switch fits snugly under LGB sleepers and have survived the harshest of weather extremes.
LGB 17100 adapted for connection to a Feedback Module.
Using a non powered Reed Switch whilst fairly reliable in operation for connection to a Feedback Module for DCC Automation, can be limiting.
Occasionally, the Reed Switches will 'bounce' and produce false triggers sending spurious requests to the Feedback Module, and being non powered does limit the potential for Automatic Operation, as is, all the Trigger Requests are sent to the Feedback Module, which then actions the requests and activates the appropriate devices connected to the DCC system.
Powered Reed Switches, benefits, eliminates false triggers, plus has the ability to produce a 5V TTL Logic Output, for connecting to a wider world outside of the DCC System.
Powered Reed Switch circuit on a strip board PCB, two resistors, diode and a capacitor, and a regulated 5V supply.
Power can either sourced from the DCC System or from a separate DC source.
Using the LM2596 DC-DC Adjustable Voltage Module to provide a steady 5V for operation, bridge rectifier, also a 104 capacitor across the + and - inputs from the bridge rectifier, has been known for these modules to oscillate on the output side.
5 Volt voltage regulator circuit designed for connecting micro processors and equipment with low tolerance to noise and voltage fluctuations.
Modified 5V Module, for DCC use, kit of parts or ready assembled, remove or replace the L7805 with a RECOM 5V (as above) voltage regulator, remove the two capacitors and replace with a 104 capacitor and a 220uF 35V capacitor, remove or replace the four 1N4007 diodes that are the bridge rectifier and replace with four UF4007 Ultrafast Diodes.
Being powered, requires an additional circuit, in the form of a Optocoupler, the Feedback Module input is a zero negative potential to a Input Contact number and GND on the module.
The two strip board PCB's connected together.
Orange and Black out to the Feedback Module.
Reed switch in an inactive state, i.e OFF.
Reed Switch activated i.e ON, continuity test to show connectivity from the Reed Switch and that the Optocoupler is function correctly, with the correct output for direct connection to the Feedback Module.
Connections to the wider world!
Just one example, Switch debounce circuit, CD4013BE 'D' Type Flip-Flop circuit, operating as a Toggle On/Off switch, controlling a DPDT Relay.
Most of the circuits shown in Blog Postings, were constructed as basic 'building blocks' to work with a variety of input devices, the outputs were tailored to whether the connecting device required a Positive or Negative input, pick and mix!