Understanding NCE's BD20

[@isaiahfurrow7414]

I'm not wanting to do anything super fancy with my layout... but I do plan to have 1 "staging" track inside a tunnel, maybe 2 tracks... I'm looking for the most simple way to know if a train is sitting in a section of tra k that isn't easily visible.... Would the BD20 be a good way to see this, with just 1 or 2 LEDs like you show.... green would mean the block is open to be filled, red would kean there's a train in there ready to come out onto the layout... I'm also looking for the easiest way to operate a pair of switches, even by button control or .... but I want to he able to throw 2 switches that align the main, or the siding that goes through staging and back to the main in the other end...., using one control...and maybe have LEDs to show which track is aligned.... Basically all others switches will be manual machines, or ground throws, or something as simple as possible.... My railroad will represent a local small RR in my area, and where it has interchange with UP & BNSF.... I have an NCE power cab, SB5, and a Cab06.... hope to start permanent benchwork and add 2 UTP panels soon, as well as start laying some flex track for the main continuous loop....so I can run trains as I work on scenery and adding turnouts for all the switching sections....I think I can run the main with only the first 6 turnouts and about 40ft of flex track...

[@LS3Jack]

The DB 20 would work perfect for detecting a locomotive on the siding. You can also use some LEDs or a by color one will also work. To control your switches, I use tortoise controllers. you can control more than one turn out with a single switch by using to12 V power supplies. You can also add some LEDs to tell you the position of those also. I have a few videos on wiring for the switches and control panels. Here is a link to start you off with kzbin.info/www/bejne/eGe4n2Skppp0iaM. I hope this helps, if you need more information please ask.

[@bulldogdona3367]

Hello again, I've learned by accident you don't need the relay to switch the LEDs. BY hooking the anodes together to the same positive lead, hooking the green LED cathode lead directly to the negative (with the resister in series), then hooking the red cathode( with resistor in series) to the switched negative, the red LED will overpower the green when switched on, turning the green off as the red one lights. You may have to adjust resistor values on the red side to get it to work correctly but it works just fine. Apparently the red LEDs pull more current than the others pulling all the current from the circuit. It makes wiring signals easier. I'm using the simple relay system you described in this video to shut off a section of track to a diverging track to prevent a crash. I installed a homemade timer to keep the relay engaged about 10 seconds after train "A" leaves the BD 20 sensored area. Then the diverging track come back live and train "B" starts back up to continue on its way. I'm starting to experiment now with using more BD 20's and a mini panel to supply some more automation with throwing turnouts, ect. One improvement tends to lead to another.

[@LS3Jack]

Thank you for the information. Never thought of doing it that way and you are correct and thanks for the update.....Jack

[@scottkahn8974]

I wasn’t able to have the green LED ever turn off using a 1k resistor on both the red and green LEDs. I’m using 12V to power the BD20

[@bulldogdona3367]

@@scottkahn8974 Use 1 resister on the common positive side of the leds and switch on the negative side. Both leds need to be common to the same resistor or it doesn't work, I usually use the positive(anode) side. I have had the green dim but not go all the way out. If this happens I put an additional resistor on the green's negative side to help restrict the current flow to it. I usually power with 5 or 9 vdc and use a 500 ohm resistor but I assume 12vdc works the same. The trick is the common resistor restricts the current flow to both so the red will consume all of the power and the green goes out. Have done it many times on multiple layouts. In fact I just finished having to wire around that problem so I could light up both a red and green signal on the opposite ends of a gantry lighting system spanning 2 tracks leaving a turnout. After the train passes through I have a BD-20 firing a signal to a mini-panel changing the lights and switching the tracks on the turnout to bypass a station. The challenge there was to switch the lights whenever the turnout switched, either by the train or the cab or a mechanical switch. It was solved by installing 2 NCE snap-its, each snap-it powering 2 red and 2 green leds. A set of reds wired back to back on one end of the gantry and a set of greens wired back to back on the other end. Worked great once I figured it all out. Of course it took 3 days. I couldn't find a relay the snap-it would close to do it the easy way. Hope this works for you, if not let me know.

[@scottkahn8974]

Thanks for the clarification @BulldogDonA! I’ve followed your guidance and now it almost works! My green LEDs are 5mm 2.8-3.2V and the red are 5mm 1.8-2.2V. The red comes on and the green dims slightly when the block is activated, but the green is still almost as bright as the red! Perhaps my power converter puts out adequate amps to power both!

[@bulldogdona3367]

very G-good video. one if the best I've watched. you've got a new fan.

[@scentgrasslakerailway]

Thanks!

[@FredE528]

I’m testing sensors with my new Arduino Mega connected to JMRI with DCC++. I have a light sensor working well on my test track but not sure it will be reliable due to light variation in my garage. If you know, can I just swap the bd20 with light sensor? I’d rap the track power wire to the bd20 and power the db20 from the 5v and gnd pins on the motor shield. Thanks for your thoughts. Fred

[@stevieruc]

Hi Jack thanks for the great video...very useful, if I may comment though , you refer to the DB20 and your file on thingiverse is for a DB20, when in fact its a BD20. Hope other viewers find this useful. Subscribed for more videos. Thanks

[@donahrens1098]

Add a second resistor to the neg side of the green. You may have to experiment with the value. I'd start with a 4 or 500 ohm and go up if its still bright. Remember you can put resisters in series (end to end) and they will add resistance value.

[@scentgrasslakerailway]

Thanks for posting that info!

[@jolliemark6294]

Interesting....thanks for sharing....Jack

[@scottkahn8974]

Can you re-post the 3D print file for the BD20? I could not find it on Thingiverse...

[@LS3Jack]

I just did a search for "DB20" and it came right up. Try that and if that does not work I will repost it.

[@cousinvinny7990]

i have an arduino 3 aspect code on my uno that works from ir sensors i can upload for all to browse what i am interested in is how you got the bd 20 to work with arduino for sending the logic to the arduino( signal sensing) and maybe the coding

[@LS3Jack]

By using pins 1 and 2 on the DB-20 and tell the Arduino when the locomotive is in that block. The sketch (code) can be found in my video kzbin.info/www/bejne/j5bGooGZn72tepo. Hope this helps.

[@TBL_stevennelson]

Nice Video's