Numerous excellent posts (here and here) describe how to use a smartphone to control model railroad locomotives, frequently using a “standard” DCC throttle or “station” as an “intermediary” that interlaces DCC commands from multiple sources and applies the resultant DCC power/signals to tracks that are picked up by one or more locomotives’ wheels electrically connected to a DCC decoder.
After reviewing these posts and understanding how this technique works, it’s a nearly effortless step to replace “DCC on the tracks” with wireless DCC transmissions to multiple locomotives. This “dead-rail” (battery-powered, radio-controlled) technique allows multiple locomotives to be simultaneously controlled from multiple throttles, be they smartphone apps or “standard” DCC throttles.
To be more specific, with minimal effort, it’s possible to use smartphone apps, such as WiThrottle, in conjunction with standard DCC throttles to control multiple dead-rail locomotives equipped with RF receivers from CVP (Airwire), Tam Valley Depot (DRS1 MkIII and MkIV), QSI (GWire), and OscaleDeadRail (ProMiniAir). Using other apps is also feasible, but I will confine this post to my personal experience and give you a specific example of how I accomplished this goal.
Of course, you will need to load a smartphone throttle app such as WiThrottle, and other apps are also for Android and iOS. For communication from the smartphone app to a standard DCC throttle, I selected the Digitrax LNWI WiFi Interface that connects via LocoNet to my Digitrax DCS52. Similar solutions are available for NCE DCC throttles using WiFiTrax and numerous other DCC throttle purveyors.
Finally, a ProMiniAir transmitter (abbreviated PMA Tx), interfaced to the DCS52 Track Right/Left output by a DCC Converter, is used as the dead-rail transmitter. This transmitter is compatible with multiple dead-rail receivers such as CVP Airwire, Tam Valley Depot (Mk III and Mk IV), Gwire, and the ProMiniAir.
The ProMiniAir transmitter is not merely a passive component in converting track-DCC to wireless DCC transmissions. It attempts to add a sufficient number of DCC “Idle” messages to the transmissions to keep CVP Airwire receivers “happy.” Otherwise, CVP Airwire receivers will not likely respond correctly to wirelessly-transmitted DCC. This feature makes the ProMiniAir transmitter unique among similar products that convert track-DCC to wireless DCC transmissions.
Putting it Together
The photo below shows the connections. If you think about it, the only aspect that is different from using track-based DCC and dead-rail is that the Track Right/Left output from the DCS52 throttle is connected to the ProMiniAir wireless transmitter (via the DCC converter that provides the ProMiniAir with 5V power and logic-level DCC) rather than to actual tracks – that’s all!
I will now walk you through the steps I used to create the demonstration below.
Connect the ends of the LocoNet cable to the LNWI and the LocoNet port on the back of the DCS52. Plug the power into the LNWI, and connect the smartphone to the network provided by the LNWI. Then select the WiThrottle app, which has excellent instructions for choosing a locomotive’s address and configuration. In our case, we use the app to select DCC address #5000, a Z-5 with a ProMiniAir receiver connected to a Zimo MX696KS DCC decoder.
You connect to the LNWI’s WiFi server on your smartphone with SSID Dtx1-LnServer_XXXX-7, where XXXX is a unique number for each LNWI unit. Upon opening your WitThrottle app, it usually automatically connects to the LNWI; if manual configuration is necessary, you connect to address 192.168.7.1, Port 12090.
Then we use the DCS52 throttle to select our Cab Forward with a ProMiniAir receiver connected to a LokSound 4 L decoder at DCC address #4292. Once you turn on track power (which sends DCC to the ProMiniAir transmitter instead of the tracks), the DCS52 throttle will start interlacing DCC commands for locomotives #5000 and #4292, sent out wirelessly by the ProMiniAir transmitter. See the photos below that demonstrate this interlacing.
Once you power on the locomotives, they listen and respond to DCC commands that match their DCC address, as shown in the video below.
I hope you will agree that allowing one (or more!) smartphones/tablets and “standard” DCC throttles or control units to control multiple locomotives by wireless is not complex at all, and that’s part of the power and appeal of dead-rail.