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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 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.

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 our free App that runs on Windows 10 and Android.

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 App. Front and rear independent light control is included in the App and supported by this module.

Fully compatible with DCC systems. Can use power from DCC Booster or separate DC supply to track.

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.