My Model Railroad with Electronics

[xrunner]

How about designing a current source switchable by TTL or 3V signal but capable of being powered from 12-15V AC/DC?

Yea that's a possibility.

Here's a short video of the traffic light project -

[Alana]

Something i made quickly as a request from polish railway modeler's forums:


Chips: 3x4011
Layout: passing siding on which every train needs to stop - thats why "expect stop" on main signal

I know its easier to use atmega or PIC but person who asked it would have to receive one programmed from me and almost everyone can solder few chips together when provided with schematics.

[xrunner]

Nice. Is something on the tracks controlling the lights or is it going to be a manual thing for the operator?

I finally got back to my traffic lights. I have them installed now but not wired up. That's the next step - wiring the electronics up under the table. Hello back pain.

[Alana]

Thats a proof of concept - i wanted polish style signaling using only TTL/CMOS logic and i got a working device. Implementation depends on the person who gave me this task.
But i have 2 unused gates that i could use for RS circuit to get what i saw in signal box. "Go" is set by push button and signals are automatically set to stop by passing train. The latter can be achieved by simple home made current relay using one of those glass tube signal relays and should work for both DC and DCC.

There is one more thing i noticed. Polish modelers like to use modular design and travel with their modules to exhibitions or meetings away from home. In such setup its better to have something typical like 4011 or even electromechanical relays because its easy to get in any electronics store and easy to fix in few minutes using just a multimeter and soldering iron.

[Alana]

My DCC system:


function decoder i'm trying to test
DCC ministation schematics and manual
DCC Gen - page contains alternate firmware for DCC ministation that i find more usefull, aslo a great resource for many DCC related things

In attachment - homebrew booster system. I found several of those chips in latest dumpster dive and decided to use them in this el-cheapo setup.
And... Dave - this project did not work

[xrunner]

Nice work Alana. It's good to understand DCC at that level.

Here's the final traffic lights in operation, and a pic of the Arduino mounted under the table. I will try to make a video of it today or tomorrow.

[xrunner]

[Alana]

Nice stuff, especially assembling those traffic lights in 1:160 scale. What are dimensions of signal head?
Have you thought of moving your traffic lights driver from arduino to some proto board with just atmega 8, oscilator, 7805 and those led driver circuts either now or when its completed?

[xrunner]

Nice stuff, especially assembling those traffic lights in 1:160 scale. What are dimensions of signal head?

Thanks - About 8 mm x 3 mm.

Have you thought of moving your traffic lights driver from arduino to some proto board with just atmega 8, oscilator, 7805 and those led driver circuts either now or when its completed?

Naw, not really. There's $9 Arduinos out there now so I'm not really concerned with using the whole thing for a project like this.

[Alana]

sory about sound - made it today at model railway exhibition.

Cars belong to one guy there and i was asked to fit lighting and for this one - forward lights for push-pull operation. DIY consists of making electric pickups and assembling 2 DDC decoders using schematic from http://www.dccdiy.org.uk/index.html [page fails to load ATM] and programing those PICs.
I may be doing more of them but probably based on different schematic and PIC program. This programing seems to be experimental and has only basic functionality and trying to change any configuration except decoder address crashes programing.
One day i may do my own DCC decoder but at the moment I'm into simpler and more useful things like block occupancy detector and reverse loop for DCC.

[rpm750]

DCC is from what I understand an open platform. There was a standard setup from the beginning and any manufacture of decoder will work on another manufactures Control system. The functions from decoder to decoder are the same as well.


It's a cool system, 12vdc with a super imposed AC signal on top of it. I work in the Instrumentation field and we have something similar called HART communication, which is over a 24v, 4/20mA loop.

[Alana]

This is last night job - big thx to EEVblog IRC chat guys who helped to debug it.

Idea is that i have DCC controlled switches for "on the carpet" style layout that i can re-assemble as i want when i want. Switch is Piko 55227 and switch machine Piko 55271. Switch machine had to be modified with simple solder blob to bypass internal cut-off switch.

Code for PIC is this: http://usuaris.tinet.cat/fmco/dccacc_en.html#dcc2coilh --> 2 turnout decoder but the same electronics will work with at least 3 other programs from that page.
My work: making it into nice small smd board you see in the video and debugging it [bad case of "i hope your next project does not work"]

And i have re-designed few boards from that webpage for my friends at model railway club so if someone wants protel files for them i'm open.