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WMH-20 Harnessed Wi-Fi Locomotive Controller

WMH-20 Harnessed Wi-Fi Locomotive Controller with Capacitive Power Maintenance


You can install this model locomotive Wi-Fi Controller in many HO scale locomotives so that you can drive them using hand-held throttles supporting the Hoffman WiThrottle protocol as used by JMRI. Examples are WiThrottle on Apple IOS, Engine Driver on Android and the popular TCS UWT-100 Universal Wi-Fi Throttle.
You can also drive using the simple throttle web page generated by the module or use our free Loco Operator App installed on your Android or Windows 10 phone, tablet or computer.

This Controller connects via a short harness either to a DCC-Ready Locomotive's 8-Pin connector or to your own soldered connections to the track power, motor and lights. You can buy various types of harness separately on our site. The controller features capacitive power maintenance which will run your loco and its controller for up to roughly 5 seconds without track power.

Full Description and Specification   Read the Quick Start Document   Read the Full Manual  

Related: Buy a Harness. Buy LEDs. More Info: Plug-in Install Solder Install.

Alternative: WMR-10 Board Replacement Controller.

SKU :WMH-20 Categories : Mobile Wi-Fi Controllers,Mobile Controllers Tag :Wifi Control

WMH-20 Harnessed Wi-Fi Locomotive Controller

This module can be easily installed in many HO scale model locomotives and provides Wi-Fi Cab Control of the locomotive using apps that run on Windows 10, Apple IOS and Android. It also contains a simple throttle web page generated by the module itself for test and basic driving.

Advanced speed control of the loco is included that uses back-emf from the motor to provide stable running at low and high speeds. The module also provides scale speed output displayed on the speedometer within the Loco Operator App. Front and rear independent light control is included in the App and supported by this module.

This module is not a DCC decoder but is fully compatible with DCC systems in that you can use power from DCC Booster or separate DC supply to track.

You can use a WFD-60 DCC/Wi-Fi Gateway to allow multiple locos with WMR-10 to appear iunder one WiThrottle Protocol server as well as other Wifitrax modiules such as switch machine controllers. The WFD-60 will also allow you to drive WMR-10 from an existing DCC system.

Front and Rear Light LEDs supplied to replace those in locomotive if necessary.

WMH-20 Harnessed Wi-Fi Locomotive Controller


Length: 33.4mm (1.32") Width: 18mm (0.71") Maximum Height: 9mm (0.35")


Installs in HO locomotives to provide direct Wi-Fi control using our free App on Android or Windows 10.

Easily connect to DCC-Ready locomotives using one of our standard harnesses or wire yourself using our flying lead harnesses.

Advanced closed-loop, back-emf Direct Wi-Fi Cab Control for HO Model Railroad Locomotives.

Front and rear light control for LEDs fitted in locomotive. The unit does not work well with filament lamps.

Comprehensive tuning capability to adjust for different locomotive behavior.

Scale speed output via Wi-Fi to operator App on Android or Windows 10.

Configurable current limiting to protect locomotive.

Power Options

12 to 18 Volts DC independent track power. Recommended 12-14 Volts DC to reduce operating temperature. This unit does not operate using AC.

Power from DCC Booster may be used as alternative to DC.

Typical 80-90mA consumption when stationary.

Typical 200-300mA when running (depending on locomotive)

Maximum peak load current 1.2 Amp. Note that the current is controlled by firmware and is adjusted to achieve the requested speed by monitoring the back e.m.f from the motor. The firmware also provides configurable current limiting.

This unit works very well with high quality modern HO motors that draw 200-300 mA when running steadily and will supply larger currents momentarily as required. We do not recomend this unit for faulty locomotives or older locomotives with motors that need 0.5A or more continuously.

Loco Connection Tips

WMH-20 Light Connections

Front and Rear Lights: The unit does not provide enough current to light filament lamps. If your loco uses filament lamps you will need to replace them with LEDs. We recommend LEDs which you can buy from our website WAL-10 LED Set or you can buy them from an electronic parts distributer such as Digi-Key (Part Number OVLAW4CB7). You may need to verify the circuitry of your locomotive and to help with this we provide the output circuits: WMH-20 Light Connections and how they expect to connect to LEDs in your loco.