Above photo is my Gosford complete with the Overhead. Click on the photo to see the Main North Album at Flickr

Thursday, July 4, 2019

Audible Warning & Announcements for NCE EB1 Circuit Breakers.

To let modellers know they have a short circuit and not a loss of power, when their loco stops, I've fitted a Jaycar Piezo Buzzer to a few of my NCE EB1 Circuit Breakers.
As of about 2020, there is a new version of the EB1s that provides a 1.5 Amp Trip Current to work with the Power Cabs. 

Early version of the EB1 with Links to adjust Trip Current - middle bottom of photo.
Jaycar XC-4424 Piezo Buzzer connected to the the early EB1, shown below.

The Piezo Buzzer connects as shown to Terminals 3 & 4 of the Terminal Block with the "S" Lead of the Buzzer connecting to Pin 8 of the Chip as shown above.

Later EB1s, easily identified with a DIP Switch to set the Trip Current.
These later EB1s shown below with my 2 lead 5.0 Volt Buzzer mounted on the Terminal Block that's used for a remote Reset Switch and LED.

The Piezo Buzzer draws 29 mAs at 5.0 Volts and I wasn't sure if the chip could supply this extra current, I didn't want to blow up the EB1. 

My mate Andrew suggested using a NPN transistor like the  BC639 that I had on hand, to operate the Buzzer mounting it along with the Buzzer onto the Terminal Block as shown.

The Transistor connections are:
Base to Terminal 3 of the Terminal Block (Output from the Chip for the external LED).
Collector to Terminal 1 of the Terminal Block (Circuit Board Negative).
Emitter (centre lead) to the Buzzer Negative.

Buzzer Positive to 5.0 Volts at the circuit Board Feed Through, shown right.

With Operators running in both Broadmeadow (lower deck) and Werris Creek (upper deck), where lots of shunting/marshalling trains can be done at the same time, a buzz from either of the EB1's that are located in the same area, it's hard to determine which District is shorted without looking at which EB1 has a flashing LED. This ia a bit hard for a visiting Operator to know where to look. Yes the trains stop when there's a short but with Stay Alive they don't stop straight away. See below.

During a recent Operating Session, Operators asked what's the buzz noise in the Trainroom when running trains and another Operator, while setting up his trains in Gosford, felt he caused a few shorts as others were having trouble with running trains through Gosford. The Gosford EB1 did not have "noise" (Transducer). The easy fix would be to isolate the track used for setting up trains - I'll do that one day.

I wondered about another solution by having an "announcement" when a power district was shorted. I'm into recycling my train stuff even if it's 30 years old. Many years ago a I made a Digital Voice Recorder from the December 1989 Silicon Chip magazine, used with my son's Lego trains.
I found the Board along with a lot of other junk under the layout, I spent an afternoon mucking around with it to see it would work for the "announcement" solution. While it provided 4 announcements, each triggered separately, I was not happy with it.

Since seeing Dave Lowe's Arduino Presention at the 2018 Modelling the Railways of NSW Convention, I bought an Arduino Uno and a Stepper Motor from Jaycar to "try" and motorize  a Turntable from an article I saw in AMRM. Nothing done yet with that project.

Browsing around at Jaycar when I'm there for electronic components, I saw a 10 second Record and Playback Module for the Arduino. I checked the details on-line and thought I'd try one instead of using the kit above, but I did not want to use the Arduino Uno to make my announcements work. I needed one of these Modules to play around with.

Jaycar Record Playback Module XC4605

Shown below attached to an NCE EB1.

The Record Playback Module needs 5.0 Volts D.C. (not 12 V) and I needed to trigger it from the EBI instead of the Arduino so I need to use a Relay but a conventional "coil" type one would create more "circuitry" in my simple logic, so I thought I'd use a Solid State Relay from Jaycar, see:

Jaycar PCB mount Solid State Relay SY4090


The Record and Playback Module comes with a Microphone installed.
Connect an 8 Ohm Speaker.
Provide 5.0 Volts DC and a "triggering mechanism" where both are normally supplied by the Arduino.

I soldered a 5.0 Volt 3 Terminal Regulator to the Capacitor on the EB1. I have since found that the EB1 has a 5.0 Volt Regulator already installed. I'll connect to that in the next EB1 upgrade.
I connected DCC to the EB1.
Press the REC Button while yelling your "announcement", to get the highest volume, numerous times until the "REC" LED extinguished (10 secs).

Pressing the "PLAYE" or "PLAYL" Buttons provided the "Short Circuit in Werris Creek" message.

Triggering the Module.

EB1 (default) Operation:
EB1's LED ON= Power to track. LED Extinguished = Short.
When there is a short. the EB1 disconnects the power to the track for 2 seconds then re-applies the power. If the EB1 still senses a short after 16 milliseconds then power is removed again for 2 seconds. This cycle keeps repeating until the short is rectified. Note the EB1 "settings" can be adjusted, see the Manual.
The Module has to be triggered each time the LED extinguishes.

Connections for the Solid State Relay are:
Pin 1 to the EB1's Terminal Block position 3.
Pin 2 to the EB1's Earth at Pin 8 of the 12F683, the IC adjacent to the Terminal Block.
Pin 5 and 6 to the "PLAYL" Switch. Note: Pins 5 and 6 connection are polarity conscious.

Now we know the the Operator in Werris Creek (upper deck), has to correct his "action" etc.

The Record Playback Module, Solid State Switch and the 5.0 Volt Regulator for the modification cost about $17.00 at Jaycar plus the EB1.

If using sound decoders, don't forget to to program the EB1's CV 135 to 4. For more details see the EB1 Manual AND Mark Gurries's page on the EB1

The completed "announcement" EB1 fitted behind the Fascia at Gosford. The Record and Playback Module is held to the EB1 with a Cable Tie and connected an 8 ohm speaker. The volume is more than loud enough with an old Traino 44 speaker with an easily made enclosure from some 27 mm (o.d.) conduit, 50 mm long.

The 6 Pin Solid State Relay "located" between the two boards, held with two links:
Solid State Relay Pin 1 to the EB1 Circuit Board Terminal Block's Pin 3 and
Solid State Relay Pin 2 to Pin 8 of the the adjacent PIC12F683 chip.
Solid State Relay Pins 5 and 6 (Blue and Yellow wires) are connected "across" the "PAYL" Switch of the Rec Play Module.
The 5.0 Volt 3 Terminal Regulator can be seen on the R/H side, soldered to the EB1's 470 uF Electrolytic Capacitor. Simple and it works.

The announcement of a "short" as a slack Operator runs against an incorrectly set Point in Gosford, see below.

If you want to make some of these "Annoucement EB1s" phone me on 02 9402 8929 for more details. I will take further photos as I make more of these "Annoucement EB1s".
I have made 5 of these Annoucement EB1s, all now using 5 Volts from the EB1 5 Volt Regulator, saving using a separate 5 Volt Regulator.