DCC block detection

[Anonymous]

Has anyone here tried the Digitrax BD4 block detector yet? It's not that expensive, and I'm considering it for some hidden track I'm about to lay. I don't plan on doing full-bore signal control and the like -- just hooking up some LEDs to the control panel to let me know when a block is occupied. Though I do like the idea that at some point I can expand it to run signals.

Any opinions on this one, or on an alternative for DCC block detection?

[rrinker]

Rob Paisley has a nice one, if you don't mind assembling a simple electronic kit - comes out to only $4 per block, too. This is the one I plan on using. http://home.cogeco.ca/~rpaisley4/DccBODvt5.html The problem with diode-drop detectors is that any undetected sections should have the same kind of diodes installed so the voltage across blocks is consistent.

--Randy

[Anonymous]

Thanks, but these days putting together circuit boards is a bit more than I'm capable of (and has never been a strong point of mine, anyway). [:)] But I'm curious about your comment about 'diode-drop detectors' -- are you saying that about the BD4, or about Rob's home-brew detectors?

Actually, the more I look at it the more Rob's detector looks like a variation on the NCE BD-20, which is a single-block detector rather than a dual-block detector.

[Adelie]

I've got a BDL-168 wired up right now, and intend to use more of them as I get track laid. The one I have is wired to the staging area and my intent is to do about what you have described-creating a control panel so I can "see" what tracks are occupied and what is open. My staging area is visible, but the control panel idea is more convenient than poking my head down to the openings in the fascia.

Thus far, I have been happy with the results of the BDL-168, which I think is essentially four BD4s with a Loconet connection. It includes a test block containing five LEDs (one to tell you the detector is on, the other for the four detection blocks in that circuit). I just received some resistor wheelsets from Tony's (plan on putting on wheelset in each caboose to allow it to detect both the front and rear of the train). I have not had a chance to install them or even set them on the rails to see how well they work. But from the detection end thus far, everything seems to work as it should.

So, while it is too soon to declare victory, things seem to be heading in that direction without any snags thus far..

[rrinker]

Well, if you can solder in decoders... the only components on Rob's detectors that you have to be careful with at all are the two transistors. You can add one part to his list, a 14-pin IC socket, and not have any concern for the IC (although the 556 is pretty robust anyway). However, I won't twist your arm [:D]

By diode-drop detectors I was referring in this case to the BD4. Yes, the NCE BD-20 is also a current transformer design. As is Bruce Chubb's DCCOD, but IMO it is overpriced - $7.50 just for the blank PC board and transformer for ONE block, plus you have to buy the rest of the parts.

I guess I'm just cheap [:D] And not afraid of PC boards - I built my own Locobuffer using Hans Deloof's blank board. $4 per block is just too appealing - it's like I can't afford NOT to add detection. For preassembled, the BD4 is about the best deal going.

--Randy

[Anonymous]

Yea, and the BD4 works out to about $6 a block from Tony's, so I may get one just to play with it, since I'm putting in an order for a PSRev and a decoder for my new Proto 2000 GP9 anyway.

Mark, thanks for your experience with the BDL-168. I may consider one of those for my staging yard, which will be the last track I lay. It would be overkill for my current needs, though, since I just want to monitor 3 hidden mainline tracks to see where the trains are and make sure they're clear of an unavoidable hidden switch or two.