Posted By Steeeeve on 01/12/2009 8:35 PM
Bob,
A lot of those features require a bi-directional operation. Not many DCC decoders have this do they?
Yes, a lot of them do, but not all.
I guess I should work up a chart of features and what they require. I'll do that later and post it on the blog. Thanks for pointing that out. Very good question.
There are quite a few features that do not require any feedback at all from the trains. (auto dispatch and release, context sensitive function controls, Novice mode helpers, etc.)
Most features require feedback from a loco, or at least a car immediately behind the loco. A couple cars could be used with several non feedback locos.
For 95% of the features there is no requirement to put feedback on every loco, only the locos where you want the added features that require feedback.
There are two features require feedback on both the loco and caboose, observation or FRED equipped freight car. Those are (1) anticollision/collision warning, and (2) broken train detection.
There is also at least one feature that works better if there is feedback from the last car in the train (caboose, observation or FRED). On the ALLY, I use F4 to change the position of the next turnout ahead of the loco.I find this is one of the handiest features and is used much more than I thought it would. I don't have to read the number off the turnout and key in a stationary address. It is really useful at night when we can't see the numbers even though I painted the numbers in white on top of the LGB turnout motors. It will also toggle the next turnout BEHIND the loco when backing up. That is handy sometimes. Other times it is a disaster when backing up. The problem is, the next turnout behind the loco might be under the train. In order to find the next turnout behind the TRAN we have to have feedback from the caboose. I don't have that working yet. Before I could fix it, I had to implement the ability to have locos automatically be aware of the last car in any train it was pulling. I did get that capability finished about three months back but it opened up so many other features that I really wanted and haven't gotten back to the "turnout under the train" problem. For now, we go back to the old way and just key in the actual turnout if the turnout behind the loco is not the same as the turnout behind the caboose.
So far, only Zimo and Digitrax have bi-directional decoders and receivers that can provide location information to a robotic processor. We need to that can tell us when a car or loco passes a way-point. The two systems are not interchangeable. However, you can add the Digitrax receiver to any brand of DCC system. You may be able to add the Zimo feedback to any system too, I'm just not sure about that. It also appears that a couple of the features I've implemented in software are also implemented in hardware by Zimo, but the Zimo solution seems to require Zimo decoders for those features.
You can add a fairly inexpensive function decoder (Digitrax) with feedback to any existing motor decoder. (Less than 20). Or, for not a lot more, you can add a sound card with feedback . (Less than 60).
There are other ways to provide way-point information, which is all that is needed to implement all of the features. RFI tag readers or bar code readers will work, but RFI would be better for outdoor use. The cost advantage of these will depend on the ratio of the number of way-points to the number of pieces of rolling stock and locos.
To implement 90% of the features you would need three way-points ( tag readers or feedback zones) for a mainline that is a complete loop, or two for a point to point mainline. You also need a way-point for each entry to or from the mainline. For a reader (RFI or bar-code) you will need a separate reader for each entry / exit to the mainline. For decoder feedback, you can use one feedback zone for all the sidings.
An example:
A layout with one loop of track, three passing sidings, and one, multi-track yard needs the following way-points to do all of the features I listed.
[*]Three way-points on the main. [*]Two way-points for each passing siding. (for a total of six) [*]One way-point for the entrance to the multi-track yard. [/list] For each way-point you would need either a reader for RFI, or an insulated rail joiner for feedback.
Let's assume readers cost approximately 75 each.
Lets assume decoder feedback receivers for four zones is 200 and insulators to form the way-points are no cost..
That makes the hardware cost of creating the way-points 450 for readers or 200 for feedback.
Now, how much for each car or loco?
All of the features require at least the loco to report its location when it passes a way-point. doing it with readers cost a few cents per loco. If your locos already have decoders with feedback, like Zimo or Digitrax, then it cost nothing. If you have to add a bi-directional function decoder then it cost approximately 20 per loco.
From that, we see that the base cost for RFI is 250 dollars higher than using bi-directional decoders, so at 20 dollars per loco we could add bi-directional to twelve existing locos that don't have bi-directional capabilities. To add bi-directional to new locos without decoders the added cost is zero if you use a motor decoder that already has bi-directional or add sound using a sound decoder with bi-directional.
There are a few ways to cut cost. For example, I put a sound decoder in a cattle car. The sound card has bi-directional built in. The sound card can either play cattle sounds, (the same ones the LGB cattle car plays) or generic steam or diesel sounds. When a visiting loco without bi-directional, runs on the ALLY, I can put the car behind the loco to provide the feedback in addition to generic steam or diesel sounds if needed. The card cost less than 60 dollars. You could use a couple such cars coupled directly behind any loco that did not have a bi-directional decoder. You could go even cheaper by installing feedback only decoders in a couple of boxcars, or add a four function light decoder to a passenger car and make sure it is directly behind the loco.
I visited a large HO club layout. They ran mostly Digitrax and had a Digitrax system. They already had block detection for their signaling system. All they would need to add all of the features would be the receivers (RX4). In their case, all it would take is 50 dollars plus come old computer and a 60 dollar interface (PR3). Then they would need to enable the bidirectional feature in any locos that have Transponding.
At the other extreme, I belong to a local club. Their large N scale layout runs on DC. They even use RAPIDO couplers and manual turnouts. Talk about the dark ages!
Since the club would need an entire DCC system and decoders, the only cost added bi direction cost would be the bi-directional track-side hardware, about 200 above and beyond the cost of the usual DCC system and decoders. The added features would be on a laptop connected when we want to use them or a old donated PC.
Since they use N-Track modules, there are plugs on every module. I could take spare hardware from home, build a wiring harness, and run all my N scale DCC trains on their layout with all of the added features except for throwing switches. I was going to make three "Y" adapters so that I could just plug in my harness, disconnect their DC pack (they have a cutout switch) and run DCC with the added features. Being technophobic, they don't want me to do it for fear it will "DESTROY" their railroad. Oh well!
It was somewhat of a surprise to me to find that in N and HO there are a LOT of cars and locos that already have feedback. One very popular brand in the smaller scales is Kato. Their DCC equipped locos, cabooses and passenger cars are lighted by decoders made for them by Digitrax. All I have to do is enable feedback by changing a CV. SoundTraxx Tsunami decoders are reportedly now including bi-directional via Transponding, although I have not tried their newest card.
For the smaller scales, especially N, there is a lot of excitement about the new SurroundTraxx system. I implemented the new features on the ALLY so that it can co-exist with SurroundTraxx and will work without any additional feedback requirements beyond what SurroundTraxx requires. In addition, once my SurroundTraxx system arrives, I think that the new position tracking routines will be able to reduce the need for the larger number of zones that the SurroundTraxx requires. I think I will be able to send virtual zone messages to the SurroundTraxx system to supply it with the zone messages it needs to make it follow the trains. To me, this seems to be a very cost effective solution. Imagine, the SurroundTraxx system can install virtual sound cards in up to 100 locos. If we add together all the cost for SurroundTraxx, feedback and the added features, we are looking at adding better than SoundTraxx quality sound for somewhere between 5 and 25 dollars per loco based on 100 locos. depending on what you already have. I worked up my budget bases on all my locos, N, HO and G (55 total) and came up with a cost of 11.32 per loco for sound.
B0B
