Converting Accucraft K-27 to battery r/c

maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
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399
Bucks/Oxon/Northants area
#41
If you want the Sierra sounds to be triggered by remote use a relay output R/C switch, rather than a solid state R/C switch, on any spare channel.
The relays isolate the Sierra from the ESC circuit.
MRW dual relay switch
Hi Tony. Looking only at its the operational description, in the link you provided, it sounds similar to the "2 way switcher" that Fosworks list. I have used that successfully on another installation but using a Spectrum R/X, Mac 5 esc and a "My Loco Sound" card. However, that device will not work, specifically noted in the installation manual, with the Rx2 receiver that Fosworks supply to work with their Omni branded T/X. As I understand it most of the Fosworks range is derived/rebranded from the Peter Spoerer range of R/C products. I will raise your suggestion with Steve at Fosworks when I speak to him today. I think the key component is "relay" and I cannot confirm if that bit is present on either of the Fosworks supplied products for this purpose. Max

P.S. As a point of note I dialled the phone number on the back of one of the manuals supplied by Fosworks to get some clarification (I'd in ignorance ordered the wrong switcher for the presently discussed installation , see above) and found I had dialled the number for Peter Spoerer - What I got was a patient recorded message telling me he no longer supplied his R/C equipment range and suggests calling Fosworks, who now market that range :rofl:
 
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John S

John S

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#42
Max, thanks for the info about the "switch".

When you speak to Steve at Fosworks, would you be kind enough to pose this question to him, what is the voltage output at the switch when it is activated.

Wondering if it set by the REC, and would it be in the range of 4.5V to 6V?


Been doing a detailed study of the info that Mike sent me, there is an auxiliary circuit tacked on to deal with a DCC decoder interfacing with the "trigger" inputs on the Sierra, have an idea fermenting!;)
 
maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
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399
Bucks/Oxon/Northants area
#43
Will do John. And many thanks for your assistance with this. Would you like me to make Steve at Fosworks aware of your interest and skills or shall I stay schtum ? ;) Max
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
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#44
I would only install a DPDT CO if the need is to maintain Battery and Track Power. That has nothing to do with turning the Battery on or off or the charging circuit that requires the battery to be off to charge. A Smart Charger will tell you if it is in Charge Mode ie off. Why a Centre Off? Well to stop any possible flash over, just a belt and braces thing really.
Gotcha :nod::nod::nod:

I don't think I've considered battery and track power in one loco - I live too simply :mask::mask:
 
John S

John S

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#45
Will do John. And many thanks for your assistance with this. Would you like me to make Steve at Fosworks aware of your interest and skills or shall I stay schtum ? ;) Max
Interesting thought, guess it may help him in for future project development, problem solving and sharing between Hobbyist's and Manufacturer's has proved beneficial in the past.....;)


Doing a spot of creative tinkering... using a breadboard and an LGB 65xxx Sound Unit, creating a similar setup to the Input to the Sierra board, it's hairbrained rough and ready, though the end result is what matters.

In brief, when the RC Switch is on (Momentary) voltage passes through it to turn something on, in this scenario the LED part of the opto coupler, this then shines onto the photo transistor (which are electrically isolated) which then produces a resistance onto the "base" of the transistor, which is enough for the "collector" and the "emitter" to conduct, and thus produces a "ZERO Negative Potential" into input 12 on the Sierra which is GND, and to input 13 which is the trigger for the Bell, same principle as the REED Switch activating the "trigger" for the Bell, same then could done for 14, 15, and 16 to be operated from the Omni (assume has the capability to operate four separate switches).

To explain it another way, when a Magnet is hovered over a Reed Switch the contacts close, thus the circuit between GND and Trigger is complete, in the above scenario the ON part of the RC Switch to the "base" is now the Magnet, the emitter and collector are the contacts, so when they conduct the circuit is complete between GND and the Trigger.

109709_9a6056dfc503420a8293923df748e779.png
 
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maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
4,190
399
Bucks/Oxon/Northants area
#46
I have just spoken to Steve at Fosworks and got everything sorted out. It would seem it was not clear from the information I gave him at the outset that the Sierra Soundtraxx card, that is installed in my Accucraft K-27 was an older non-DCC version. One vital component, an Rx3 receiver, will be substituted for the supplied Rx2. My apologies to Steve for any impression I may have given that there may have been any lack of understanding and knowledge on Fosworks part in any of my posts. I have decided after discussions with Steve to go ahead, on my own account, and have incorporated a PWC/PWM linear converter (have I got that right John ?) between the Cobra esc and Sierra card. We now have the way forward.

John S - it looks as though Fosworks has the right "old school" switches in stock, though not listed, to operate the 2 sounds on the card that would benefit from manual r/c operation from the Omni transmitter rather than via reed switches. So there will be no need to incorporate those into the PWC/PWM linear converter that you are building.
 
Tony Walsham

Tony Walsham

Manufacturer of RCS Radio Control.
25 Oct 2009
2,063
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Casino, NSW
#48
If you want to hear the "at idle" sounds of a Sierra sound (Fireman Fred etc) and you are connecting any solid state trigger to the Sierra, you will need a common ground with the trigger and therefore must use an opto coupler on pins # 7 & 8.

Or it can be done as shown above by John S. One opto coupler per sound trigger.
Sierra themselves showed a circuit on how to do it.
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
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#49
Gotcha :nod::nod::nod:

I don't think I've considered battery and track power in one loco - I live too simply :mask::mask:
It does make a lot of sence if you are doing a DCC Loco to Battery Power as then you can use a DCC System to do any CV Revisions, also will work on a DCC Line if you want it to. My first DCC Conversion will not have the option as it is a rubbish runner on DCC Track Power anyway ( Train Line Pffifi), but subsequent ones will have the dual option.
 
John S

John S

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#50
Board constructed, passed voltage tests, motor test have to be done tomorrow, have a weather warning in these parts, restricted vehicle access on the A38 across the Tamar Bridge, long and convoluted detour around the A30, day job beckons with an earlier start time.

109775_02e8042030e10f87f4019f445c88a5b6.png
 
maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
4,190
399
Bucks/Oxon/Northants area
#51
If you want to hear the "at idle" sounds of a Sierra sound (Fireman Fred etc) and you are connecting any solid state trigger to the Sierra, you will need a common ground with the trigger and therefore must use an opto coupler on pins # 7 & 8.

Or it can be done as shown above by John S. One opto coupler per sound trigger.
Sierra themselves showed a circuit on how to do it.
Hi Tony very much appreciate your suggestions. However, I am a simple soul and the terms - "common ground", "solid state trigger" and "opto coupler" are meaningless to me . And I do not posses or know where to find Sierra's schematic to do this.

I know what I want to achieve - converting my track powered Accucraft K-27 to r/c controlled battery power, while retaining all the sounds, at idle or voltage induced and otherwise and to overcome some operational shortcomings that have shown up on my line as built that are not exhibited by any other of my track powered locos. Hopefully without messing around too much. If that cannot be done then I will just bin the conversion and live with it as a DC track powered loco. Max
Board constructed, passed voltage tests, motor test have to be done tomorrow, have a weather warning in these parts, restricted vehicle access on the A38 across the Tamar Bridge, long and convoluted detour around the A30, day job beckons with an earlier start time.

View attachment 245331
Wow ! Great stuff. Thank you, very much appreciated. No hurries. Max
 
John S

John S

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#52
Motor test complete, adapter board does what it should.

Non technical explanation to how it all goes together, first off how the existing RC Switch you have can be used.

109847_bf9f5ae73854d54d4dee2cab75b10d1e.png




The Sierra Battery Adapter Board......

109845_7941597021a75e324be63d46f232fea5.png
 
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maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
4,190
399
Bucks/Oxon/Northants area
#53
John that is wonderful. Thank you. However, I have returned the switches you are showing at Fosworks suggestion as I'm told they will not work with the Rx3 (or the Rx2 for that matter) in this application. Alternative connectors, "of an older type", are being sent by Fosworks for use with the Rx3 to connect directly to the Sierra card. Or that is what I understand. These are not listed on their site so I cannot tell you what they are or how they work. I'll post pictures here when I receive them. I am becoming very confused. Max
 
John S

John S

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#54
Ok no worries about the switches, case of wait and see what appears from the postman.

I'll post a picture for you on what should connect to where, to connect the Cobra to the Adapter Board and from the Adapter Board to the Sierra.
 
John S

John S

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#55
110157_527452fcdbdbe076f3cb2b03a00cde73.png


110159_02007d98d4409c435518f5b07c3f96f9.png


From the notes, the Battery Connector on the Sierra Card can be troublesome, softly, softly approach should be used, if for instance the onboard battery is plugged in, I'd suggest leaving the plug & socket alone, sniping the wires to the battery and splicing on new cables to the Sierra Adapter Board.

If troublesome, please send to me and I'll concoct or fashion a more robust connection.

There is a reference on the t'internet to use the connections marked 2 & 4 to connect up an external supply, only one result is guaranteed if this is followed!

Puff the Magic Dragon will look tame compared to the amount of smoke that will bellow out of the Sierra Card!


The Good Lady going on the Bus to Exeter taking it with her to the Post Office, then it's at the mercy of Royal Mail!.......
 
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maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
4,190
399
Bucks/Oxon/Northants area
#56
Thank you John. You are going to have to give me a little time to inwardly digest this :happy::think:

First thing that meets my eye is it appears we are doing away with the Sierra's 6v lead acid power supply and replacing with the loco's 18v as a common supply. Is that so ? This will do away with the Sierra's tender mounted switch and mean I can get rid of its wiring, grounded on the tender's chassis at one of the speaker mounts. I will also need to replumb the voltage controller in the tender, for the rear facing light, that is similarly grounded on the same speaker. I think I can work that all out.

There are 2 pairs of wires on the MOT outputs on the Cobra, 1 pair can go to motor, 1 pair to the Sierra. There are 2 pairs of wires on the +ve & -ve input terminals on the Cobra, 1 pair are the inputs from the battery, the other pair are in effect "tapped in" wires (in parallel to those from the battery) that can be wired as shown, via the card you have supplied to provide 18v power (instead of 6v at present) to the Sierra - so there is no need for the additional wires to tap into the as you have shown in the first image. Am I right ? Deep breath.

I'm somewhat filled with trepidation with regards the "Puff the magic dragon" metaphor :smoke::eek: but I'm not planning to change anything there as one wire on the volume control is on 4 (as well as 1 & 3). I shall gird my loins and proceed with caution. Max
 
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Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
22,682
2,773
North West Norfolk
#57
Thank you John. You are going to have to give me a little time to inwardly digest this :happy::think: First thing that meets my eye is it appears we are doing away with the Sierra's 6v lead acid power supply and replacing with the loco's 18v as a common supply. Is that so ? This will do away with the Sierra's tender mounted switch and mean I can get rid of its wiring, grounded on the tender's chassis at one of the speaker mounts. I will also need to replumb the voltage controller in the tender, for the rear facing light, that is similarly grounded on the same speaker. I think I can work that all out. I'm somewhat filled with trepidation with regards the "Puff the magic dragon" metaphor :smoke::eek:. I shall gird my loins and proceed with caution. Max
Never let the magic smoke escape :shake::shake::shake::shake::shake:
 
Tony Walsham

Tony Walsham

Manufacturer of RCS Radio Control.
25 Oct 2009
2,063
35
Casino, NSW
#58
BIG SNIP!!
There is a reference on the t'internet to use the connections marked 2 & 4 to connect up an external supply, only one result is guaranteed if this is followed!

Puff the Magic Dragon will look tame compared to the amount of smoke that will bellow out of the Sierra Card!

SNIP
Yes, that can happen if the battery supply is over 12 volts.
The # SSI-12v5 after market Opto coupler device I used to make for Sierra sound pcb's was designed by Sierra and permitted up to 12 volts to be fed into the Sierra pcb to replace the 6 volt battery. PDF instructions The 12 volts was provided by a proper 12 v regulator.
+ 12v on terminal # 4 and - on terminal # 2.
If you used only 6 volts you could not get a Sierra diesel sound to ramp up to notch 8.
 
maxi-model

maxi-model

UK/US/ROW steam narrow gauge railways 1:1
27 Oct 2009
4,190
399
Bucks/Oxon/Northants area
#59
So we are reinforcing the warning - do not use terminals #2 & #4 on the Sierra's board to apply power from an 18v source ? As I have mentioned there is not much risk of this in my mind as they are already taken up with another function, along with #3, to provide for the Sierra's volume switch. But as John has set it up on the card he is supplying me with, to pass and then input power at the point shown on the schematic, it is perfectly ok ? Max
 
John S

John S

Registered
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#60
Thank you John. You are going to have to give me a little time to inwardly digest this :happy::think:

First thing that meets my eye is it appears we are doing away with the Sierra's 6v lead acid power supply and replacing with the loco's 18v as a common supply. Is that so ? This will do away with the Sierra's tender mounted switch and mean I can get rid of its wiring, grounded on the tender's chassis at one of the speaker mounts. I will also need to replumb the voltage controller in the tender, for the rear facing light, that is similarly grounded on the same speaker. I think I can work that all out.

There are 2 pairs of wires on the MOT outputs on the Cobra, 1 pair can go to motor, 1 pair to the Sierra. There are 2 pairs of wires on the +ve & -ve input terminals on the Cobra, 1 pair are the inputs from the battery, the other pair are in effect "tapped in" wires (in parallel to those from the battery) that can be wired as shown, via the card you have supplied to provide 18v power (instead of 6v at present) to the Sierra - so there is no need for the additional wires to tap into the as you have shown in the first image. Am I right ? Deep breath.
I'm somewhat filled with trepidation with regards the "Puff the magic dragon" metaphor :smoke::eek: but I'm not planning to change anything there as one wire on the volume control is on 4 (as well as 1 & 3). I shall gird my loins and proceed with caution. Max
Correct, the Sierra 6V Battery is no longer required. The voltage regulator is now no longer required and can be removed (likewise the one for the front light is also not needed). The Sierra Card has two onboard regulators, which take care of the supply for the internal electronics of the card and provide a fixed voltage output for the lights on 6 & 5 (NEG) and 4 which is the Positive out.

That will certainly make for easier connecting everything together.
The Battery Pack will be supply 18V, to the adapter card, which performs two functions,
1) Reduces the input voltage from 18V to around 7.29V* to supply the Sierra Card for it to operate correctly, sound, lights, triggers.
2) Converts the PWM in from the Cobra, to a linear DC voltage for the "chuff" etc, on inputs 7&8 on the Sierra Card.


Steady as you go, one step at a time, and it may surprise you, it is a lot less complicated than it appears!

*Technical note for the curious! The regulator as per the original schematic is set to around 8V, it varies slightly based on the value of the 5% resistors used to regulate the output, which is protected by a 1N4xxx diode which drops the voltage by 0.7V.

To keep the equilibrium from the original circuit, the 1N4xxx was changed for a 1N5xxx type, which reacts faster to a short circuit and has a minimum voltage drop, the DC to DC converter voltage output was adjusted to suit the original specification.
 
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