Fitting the DRS Bachmann Class 57/0 locomotive pair with Bif. LokSound V4. Decoders.
The sound quality and driving technique of the Legomanbiffo (Bif.) sound equipped Network Rail 57/3 was sufficiently impressive to prompt a switch to the same LokSound V4 fit on my two DRS Class 57s, used on the MOD nuclear train. The main changes required are due to the much less flexible function output arrangements of the ESU LokSound, when compared to the Zimo decoders. However, with fairly simple lighting arrangements on the Class 57/0, it is not necessary to provide an additional function decoder. Instead, discrete component buffer amplifiers will be fitted to enable the LokSound Aux 3 & 4 logic level function outputs to be used without recourse to the ESU adapter board, which is almost certainly too big for this application.
Class 57/0 at York station in 2008.
|The Planned lighting
Because the locomotives are used double headed within the train and occasionally in double headed light engine configuration, independent control of the (directional) lights at each end of the locomotives is a requirement. The following arrangement is therefore proposed: (FO = "function output")
(1) Directional lights at end one, activated by button zero. (Headlight FO to end 1 forward lights and rearlight FO to end 1 rear lights).
(2) Directional lights at end two activated by button 14. (Aux1 FO to end 2 forward lights and Aux2 FO to end 2 rear lights).
(3) End 1 driver's cab light activated by button 11 (Aux4 FO plus buffer amp).
(4) On lead loco 57011 only: Detonator flash LED activated by button 17 (Aux3 via buffer amp).
(5) On rear loco 57012 only: Connector feed at end 2 to enable some (dubious) effects in the front nuclear flask carrier, enabled via button 20 (Aux3 via buffer amp).
Revised Class 57/0 Interconnect:
The original Bachmann yellow marker light LEDs have been replaced with new pure white types to represent the real loco's current LED technology marker lights.
Alternative discrete buffer amp circuits: (Depending on which bits I have available when the decoders arrive.)
The N-channel MOSFET solution uses just a single surface mount (SOT23) size component per FO, which is small enough to fit on the main PCB, but just large enough for hand soldering with thin wires.
The NPN transistor circuit is believed to be similar to those on the ESU adapter board.
In both circuits, the load (which must include a suitable series resistor) is connected between the buffered output and common positive. The Aux3 and Aux4 decoder outputs are believed to be at ground voltage when off and at +5V (wrt ground) when active. They have very limited current handling performance. (The MOSFET solution was finally chosen.)
Programming the Decoder:
|Active Button Sound Slot
Assignments (& Lighting Controls):
Most of the sound slots (at least all of those I've checked) are set at maximum volume, so to make any of them sound louder compared to the diesel engine sounds, I've had to reduce the volume of the engine sounds in sound slot 1.
Motor Control Settings
Smooth running is achieved across the entire speed range, but I'm sure many other combinations will achieve the same result!
The Legomanbiffo sound project includes a triple detonator sound sequence. I've fitted a tiny chip LED on the frame of the front bogie near the bottom of the front wheel. The wires are fed up to the main PCB through the same holes as the wheel contact wires. The LED is connected to the Aux3 function output buffer via a 1k resistor. I operate the loco using PC control and I can briefly activate the LED using the Traincontroller software, at the same time as the detonator sounds occur. To see this in action on YouTube, click on the link immediately after the detonator flash photo below.
To watch a You Tube clip showing the detonator flash, click here.
I've also cooked up an electrical circuit that will produce similar results if computer control is not available. It consists of an astable multivibrator with the "on" time for the LED of around 100mS and off time between flashes of about 1.25 seconds. The astable circuit is held with the LED "off" by the third transistor, until a negative going output is provided by one of the decoder function outputs, which should be activated simultaneously with the detonator sounds.
If you build this circuit, the values of the resistors marked with a star will need fine tuning to get the timing right, as the tolerance of the electrolytic capacitors used, is very wide. The 680K controls the flash repetition time and the 100k is adjusted to provide just three flashes whenever the detonator flash is activated. The transistors are low power NPN devices with a reasonable gain (eg BC549C). The diodes are there to prevent reverse breakdown of the transistor base-emitter junctions and are ordinary small signal types (e.g. 1n4148). The idea is to modify the function mapping of the LokSound V4 decoder to trigger the function output from the same button that initiates the detonator sound. The button needs to be left "pressed" for at least the duration of the three flashes, before being re-set.
To watch a You Tube clip of the finished 57s with the MOD Flask Train, click here
Adding some useful ESU "logic functions":
Included in the ESU LokSound V4 are several additional features that can be assigned to any available control buttons:
Using the functions section of the comprehensive V4 manual, these steps activate the sound fader and the manual diesel notch control.
1) Volume fader: Fit to button 21: Set register CV32 to 3 then set CVN=CV429 to 8. Set CV133 to 75 for a little over half volume.
2) Diesel Notch-Up: fit to button 22: Set register CV32 to 3 then set CVN=CV445 to 2.
3) Diesel Notch-Down: fit to button 23: Set register CV32 to 3 then set CVN=CV461 to 4.
Revised Sound & Light Control Function list
|F0 End 1 directional running lights|
|F1 Sound On/Off and engine start/stop.|
|F2 Playable High Note Horn.|
|F3 Playable Low Note Horn.|
|F4 Buffer Clash/Buffering up when moving slowly.|
|F5 Air Release (Air Dump).|
|F6 Drivers door slamming.|
|F7 Compressor Startup.|
|F8 Spirax valves.|
|F9 Flange/Wheel Squeal Enable.|
|F10 Dispatcher's whistle.|
|F11 Driver's Cab Light|
|F12 Roof Fan/Cooler Group|
|F14 End 2 directional running lights|
|F17 Detonator flash. (Loco1 only)|
|F18 Triple Detonators.|
|F19 Set zero momentum (for test purposes only)|
|F20 Flask flash. (CV 0/291=12; CV112=10) Loco 2 only|
|F21 Volume Fader.|
|F22 Diesel Notch-Up.|
|F23 Diesel Notch-Down.|
|Supplier website links:
The photos of the models were taken using a hand held Canon Ixus 220. The photos of the real 57012 loco were taken back in 2008 at York Station.