I'm back with a new and different project. I'm building a DCC system in a box to power my home NTrak layout as well as to take to NTrak shows to improve operation. Rather than do a step-by-step how-to I've gone a different route focusing on why I made the choices I made, and what things you should think about while building your DCC system. This is a multipart effort, it will take several blog posts and YouTube videos to show all of the details. I've shot a lot of footage, and I'm just starting to turn it into articles. In real life I'm about 90% done, and let me tell you the final product is going to be great! The series kicks off with my "givens and druthers" article and a teaser video. See: http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/5/13_DCC_and_Portable_Layouts.html http://www.youtube.com/watch?v=pkAOkhpPor8 I've also gotten the first segment done, which is all about how I'm powering my box. I think you'll find I'm doing something a bit unconventional for a model railroad by borrowing from the Ham Radio community. http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/5/21_DCC_in_a_Box_1_Power.html http://www.youtube.com/watch?v=Cg72SiWUeZU I'm starting a thread on each of the major forums to try and keep all the comments and questions in a single thread. I may be a little coy until the entire set of segments is up, but rest assured I will answer any and all questions. As always, I also want to know how your DCC system is set up. I encourage folks to make video responses and post them on YouTube, or write on your own blog and link in one of these forum posts. At the end of this project I'll post a wrap up article in my blog with links to all the videos and articles I can find.
The second installment is here, talking about command stations, boosters, and power management. See the blog post and YouTube video! http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/5/23_DCC_in_a_Box_2_Command_Station_and_Boosters.html http://www.youtube.com/watch?v=AJzwkkaKdYg
Another installment, this time on RRampMeters and monitoring your DCC output. See my solution to panel mounting them! http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/5/25_DCC_in_a_Box_3_RRampMeter.html http://www.youtube.com/watch?v=GDrmqLCc59s
A new blog entry on LOCONET http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/6/4_DCC_in_a_Box_4_LocoNet.html Complete with a new video http://www.youtube.com/watch?v=LXcnaOA2Brw Thanks for following along!
Final Assembly, and an unintentional cliffhanger! http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/6/10_DCC_in_a_Box_5_Assembly.html http://www.youtube.com/watch?v=JOzshbWBlIc
DONE! It's done, mostly! This video and blog post documents the completed project, and I'm really happy with how it turned out. There is however still one minor problem, which I describe in this video. http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/7/5_DCC_in_a_Box_6_Complete!.html As I state in the video there will be one more follow up video with the nitty gritty technical details of the problem I ran into. That video is done and ready to go, I just have to write the blog post to go with it. I think there's a good chance I will have it up tomorrow.
I now have up the electronics detail on my problem. As I stated in the completion video, there is a problem where the high amounts of capacitance in the Digitrax boosters are interacting badly with my MOSFET based electronic switch in the power strip. I think I have a solution, but I need some electronics gurus to look it over and make suggestions; or at least check that my work is right. http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/7/6_Too_Much_Capacitance.html
Leo, The concept is good, but there are some problems with the implementation. See my posts over on that other website or on your blog for details. Short answer for the viewing public: The N-MOSFET is wired up backward, but it won't work anyway. You need a P-channel MOSFET to make it work. Also, the R/C values are OK but might want some tweaking for better performance.
Nice work, Leo! Cupple o' comments: 1) The dual exhaust fans are a good idea, but unless you are going to operate with the back off, you might want to add an air inlet (lower right side or bottom would do). 2) It seems that you are going to mount the PSX-4s out at the layout. This means long DCC runs (albeit on #10 cable) before getting to the PSX, plus whatever runs there are on the modules. The possibility of DCC signal degradation has long been an argument against centralization of boosters (although it still seems to work - go figure). An alternative (if you like cabinetry), is to add support for "Remote Booster Boxes", putting a DB200+ (with a "MOS-FEET" thingy), RRAMPmeter, UP5 and PSX4 in a box and use the 30 ft extensions to feed it with 14 VDC (white line PP configuration). Add Booster common (green wire, which could be included as a 3rd wire in the 30 footers) and LocoNet and you're done. This model would also work with individual AC supplies (MF615, etc) if you don't mind extra AC plugs and/or the battery backup feature was not important to you. I actually kinda like the 14VDC distribution version as it saves on AC plugs, which are always in short supply at the venues, and 30 ft of #10 is cheaper than a MF615 (although not by much).
I didn't show them because I thought they would be boring, but there are in fact two inlets the same size as the fans on the opposite side. Looking at the box from the front, the two fans are on the upper right side, the two intakes are on the lower left side. Nice to see someone paying attention though! Having read a lot about this problem I really think it is a non-issue. I think the problems in the past have been driven by various wiring problems, from using small wires (e.g. 18ga zip) and bad connectors (CJ's) to running the lines parallel to AC power for long distances (say, a whole row of modules when we still had power strips on them all). I think by using #10, unbroken wire, laid not near other things it will just work. Indeed, on some level I think I hope to prove that!
I have found a solution to my problem and will soon be documenting it with a video and a long blog post. In the mean time, something to keep you interested in my DCC progress, the installation of an MRC sound decoder into a Kato P42! http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2010/8/21_Kato_P42_MRC_Sound_Decoder_Installation.html
Whee! It's been a long time since I posted on this, but I finished the project and made the remotes, and now have them working with JMRI. Check out the last two blog posts! http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2011/1/24_DCC_in_a_Box%2C_The_Final_Solution.html http://www.realityreduced.com/Reality_Reduced/Blog/Entries/2011/1/26_Power_Management_and_Feedback.html
