Hi guys,

Well thanks to Brian and his wonderful UBW design and firmware I was able to get up and running on my first ever PIC project in very short order. Thanks Brian for such a great learning tool!!

I also used Brian's code to help as an initial structure to my own, gradually removing bits of the UBW code I no longer needed, but keeping enough to *really* help me in my debug+learn mode

It's been some time since my last post - I've been busy with PCB layouts, prototypes and so on - I thought you might like to see what I've been up to

Here's the first prototype on breadboard (I was too stingy to buy a UBW from Sparkfun)... very ugly but it did prove a concept:



Then here's the first single-sided PCB made at home:




And finally we get to version 1.1, near-to-final design:



And finally... what's all this for?? Here:



...which just goes to show you can combine two favourite hobbies

BTW: I already have orders for 60 of these... so commerce from hobbies is possible too Will have more details on my website in due course for those interested.

Regards,
Paul[/url]

Paul,

That is so unbelievably cool! Your boards look great. Can you describe more about what it is (exactly) it does? I'm a little bit into MR myself - I tried to get into the DIY DCC scene a few years back but not much came of it. UBW sure is an easy and powerful way to prototype things.

Thanks so much for sharing-

*Brian

Hi Brian,


Thanks! I used ExpressPCB's software as it's sooo much easier to use that everyone else's favourite Eagle. Then I printed the designs onto Press-n-Peel Blue, ironed them onto the blank PCB and etched in ammonium persulphate... easy

Of coure I will have larger quantities made for me - last I did PCB design I used a 486 running Windows 95 about 10 years ago to do a large 4-layer board that used a 68000 cpu. PICs are *way* easier to work with


I too dabbled in DCC recently, think it was the only way to go. What I discovered surprised me:

* DCC is expensive - $100's to buy throttles, boosters etc. and THEN you need to equip each loco. In my case, N-scale, this is quite a bit more expensive than for HO, O etc. with prices here in Australia of $AU90 per decoder.

* DCC is hard to control - when working alone on my small layout it was easy to manage one loco, but DCC's main advantage is in handling many simultaneously. Trouble is, the human mind is NOT For an individual running a layout DCC is no more advantageous than DC. Of course when you have 10 of your best MR friends around DCC can be a lot of fun.

Then I re-joined my old MR club and the case against DCC got worse.

* Many of the members are over 50, with a good many over 70. These folks have many locos, with more than one of them having 200 or so. DCC converting them all, or even an interesting subset, would be prohibitively expensive.

* The club funds itself through exhibitions to the public at shopping malls etc. This requires automated running of 20 or more trains to make them appealing/enthralling for the audience. DCC is little help here, as you either need 20 volunteers manning the layout for 7 days straight, or you need a computer and a whole bunch of software/programming effort.

Automated control of the 20 or so locos on current layouts has hitherto been done *electromechanically* with dozens of telco-grade relays running on 48v wired into a kind of primitive computer (us Aussies are clever that way - it's amazing what we can do with fencing wire ) All this required kilometres of wiring back to a central console/rack and is prone to breaking oddly.

My goal was to improve upon this with modern digital control in a totally expandable fashion. Our new layout *could* run 50 locos if we could control them well... and would be a stunning display as a result.

The controller shown provides full digital control of the regulated rail voltage using digital pots and a linear regulator... providing complete software control over simulated inertia. The USB interface is used for field updates of firmware and event reporting/control to a computer for centralised control.

The RS422 serial bus, opto-isolated inputs and relay outputs on the board allow for what I call "emergent control" Basically you plug as many of these together as you like to fully automate a DC-based layout, without need for a central computer (though the addition of it allows some clever things). The protocol running between the boards allows for semi-automated and manual control as well.

A variant of the board uses an RFID readers for sensing RFID tags under locos and DB lookup on SD-card flash memory allows programming of individual loco characterstics including acceleration, braking and running speeds (and sounds later.) This board also handles the RS422 protocol and is inserted into the control loop to allow controllers to be sent loco-specific data.

Wireless hand-controller versions will allow for semi-auto and manual control/intervention, with the wireless base station again inserting itself into the control loop.

All digital I/O is expandable to allow for controlling larger numbers of signals, points and so on.

<whew!> When I describe it all like that it sounds like a lot Much of the cleverness is in firmware and the protocol the controllers use to talk to each other. The proof will be in the pudding as they say, but the thought of 50 trains running around a layout without human intervention is exciting to say the least.

Regards,
Paul

I thought it was time to show you the new double-sided PCB version of my UBW-inspired controller. A few bugs still in the layout, but it's a good deal easier to build and more robust than the initial single-sided prototypes. I've made 60 of these for the pre-production run.

The one shown is presently partially built as I follow my bring-up procedure and debug the many lines of code it now runs I'm running the RS-422 links over the RJ45s at 1Mbps with multiplexing on the inputs. At the top is a switchmode power supply for the 5v which runs so cool it doesn't need a heatsink (yay) though there is provision for one as it's better to be safe than sorry! The board takes any old ac or dc voltage from 15->24v (15vac typical.)

The heatsink you can see is for the 3A digitally-controlled linear regulator for dc motor control. Relays for outputs and AC compatible opto-isolators for inputs. The 74HC595s and 597s allow for a great deal of i/o expansion (32-64 bits each is easy.)

Let me know if you have questions.
P.

Here it is:

Very nice! I haven't done any model railroading since I was a kid, but this makes me want to pick it up again. Maybe when I retire...

nice job who did you use for the pcb's?

Thanks - I used ExpressPCB (www.expresspcb.com) The only downside to using their very simple and quick PCB layout software is that it outputs a binary format that is not Gerber. This prevents you from using other PCB fab companies, but when I did an extensive survey of costs I found ExpressPCB to be very close to most of the others... especially if you need more than 20 units.

I ordered 20 units of a PCB the other day with their 2 day manufacturing turn-around option and received the boards in Australia 5 days after placing the order. Not bad really...

P.