Hey guys, I've been doing plenty of research into building my own version of a BD20 for block detection on my n scale layout. So far I have found the following article from A-train systems regarding a DIY bd20 using the easily available 1000 wind current transformers from Aliexpress. https://www.a-train-systems.co.uk/projects.htm#BlockDet I was wondering if anyone out there had purchased the boards from OSH Park and made one? I have about 30 to make and would rather buy in bulk than just a few items to make one to test, so hopefully someone out there has had a crack already and can let me know if its worth the effort? Cheers Chris
I did test several concepts for current transformer block detection and the only one giving sufficient signal amplification, selectivity and sensitivity was the one provided by JLC entreprises (I think based on a design by dr. Bruce Chubb). You can find the schematic and full description in this article. From his concept I designed my own pcb. If you are interested I can send the schematic (pdf) by pm. EDIT: but in general this concept of block detection is the best possible solution for its purpose. All sorts of diode etc detection systems just do not work properly. This idea does, and without interference with the track DCC signal.
Thanks Erik, Does your version produce an analogue signal that needs an Arduino or the like to compute or a digital signal? scratch that. Just had a good read of that article and the answer was right there.
Well, I ordered a small sample of these and finally got them made and had a test run. So far they work great, plenty sensitive enough to detect a stationary loco on the track. Haven’t tried a resistor yet - but then don’t plan on fitting any to my wagons. worked well with a very simple arduino sketch. Next step is to get the network up and running and see how it interfaces with JMRI. can highly recommend them. Just ordered another 30 boards and so far it’s cost me about $70 including all the components. Bargain!
