Just a bit of an update and my take away so far. Some new questions at the bottom.
1. What is the price point people would find reasonable for this product? In the simplest implementation I can do right now the bridge would allow control of up to three LC/+ locomotives from your Cab1/2. the hardware needed to accomplish that, however leaves plenty of room for expandability.
2. Is it worth while to increase the initial cost of the bridge to make it expandable to control more than three LC/+ engines? I am not entirely certain, but expect that it would add around $10 to the cost to provide for expandability. In exchange it will cost about half as much as the first bridge to add another module to control three more engines.
It looks like most folks think $50-100 would be a reasonable price, with $150 being top end. Since my expected parts cost is well over $50, I don't see that as a possibility. I need to design a proper PCB and price out parts for the final design before I'll know exactly how much it will cost to build each unit, as well as knowing some of the other things below to settle on a final design. I have 2 major options at this point. I could use an expensive microprocessor that would allow for expandability and other features, or I could use an inexpensive one that could only ever control 3 engines. I need to test some compatibility with LCS before I can fully commit to one option or the other (more on that below). In any case, Right now, based off known and estimated parts and labor costs, I'm expecting I could offer the basic, 3 engine model for around $120 and the expandable version for about $140. I hope to reduce those estimates, but that's where I am right now.
3. If an expandable design is chosen, how many LC/+ in total should it be capable of supporting? I think I can manage up to 24 total LC/+ engines from a fully expanded bridge before another "master" unit is needed. I won't know for sure until the code is written, but may run into other issues with a single master device controlling so many engines. Would a unit that can only be expanded to control 12, or 6 total engines be acceptable?
It looks like 18 engines will be the limit at this time. I may have to reduce that to 15 or 12 as I write the code, but with what I have so far, 18 seems to work. Of course, if someone needed to control even more LC/+/FC engines at once, they could use a second bridge device that could support up to another 18 engines. perhaps worth making note, you don't need the bridge to have a channel for every LC engine you own, just however many you want to run at the same time.
4. Are tactile, physical buttons and switches on the device for programing preferred or wanted? The implementation i'm currently working with uses the cab1/2 remote for most programing with perhaps 2 buttons on the bridge it's self. Do people prefer to use buttons or switches on the bridge to program it, or is it ok to program from the Cab remote?
It looks like some folks prefer the physical switches and buttons, but it's my estimation that more people would prefer a lower cost and the ability to control more engines. Since everyone that will use this product has a cab1/1l/2 i'm going to make the programing from the remote. I already have that part of the program code working right now. At the moment the bridge has a set of dip-switches to set its programing address, but I may do away with those as well. at present the programing method is as follows.
ACC =>
(Two digit bridge programing address) =>
AUX1 => (Number 1-9, for which LC Channel you want to program) =>
AUX1(LC 1-9) (AUX2 for LC 10-18 (adds 9 to number pressed) ) =>
ENG =>
(Two digit TMCC engine address desired) =>
SET
This sequence is pretty straight forward on the CAB1. Is it equally simple on a cab2?
5. Is there anyone in the Metro Detroit area that has a functional layout with Legacy AND LCS that might be willing to volunteer some time to help do some testing to insure the bridge is fully compatible with those systems? (DCS as well would be nice.) It is my intention for the bridge to be installed with the 9-pin serial port on the command base, and for any additional serial devices to then plug into a second serial port on the bridge device. I can think of no reason this won't work, but need to test it. It would also be nice to test the bridge with Legacy and DCS for compatibility. Once any obvious bugs are worked out, I'll probably look for a couple "beta testers" to try the device on their layouts.
On to the new stuff: