This article was submitted to BMR by our good friend Gareth Ellis, who discusses his experience with DelTang control systems in his models. Thanks Gareth!

Introduction

DelTang RC Control systems is a well-designed radio control platform, with many benefits for a growing LEGO® model train community. The system comprises of a transmitter and receiver, bound with each other for discrete, individual and reliable control.

The basic principles of DelTang radio control for battery locos, in its simplest form are a transmitter and a receiver that has an integrated Electronic Speed Control unit which in turn is connected to batteries and a motor. When the throttle knob on the paired transmitter is moved the motor increases or decreases in speed accordingly.

DelTang currently produce many transmitters and receivers for a wide range of model control, we will focus on Model Train specific variants of the transmitters and receivers. As there is such a wide range we will cover the TX22 Transmitter and the Rx-65 (22) specifically. At the time of writing this, the TX2 was on V207, and the Rx-65c (22) was on V611.

DelTang manufacturer the transmitter and receiver cards, also make a controller kit, however other companies such as RCtrains.co.uk and The On30 Guy,  make controllers that include the DelTang transmitter cards.

Features

Some of the attractive attributes of the DelTang devices include its size, the Rx65b receiver is a tiny 3x14x38mm (0.125×0.6×1.5″) card, and with this incredibly slim size, this receiver can be slipped in to the tightest of spaces, leaving room for batteries, and MOC design internals. RC 2.4Ghz that the DelTang system communicates on allows for no line of site, this means that the receiver can be buried deep in the model without any concern for control loss. RC 2.4Ghz provides many other benefits, including a reported range of up to a whopping 90 meter (300ft) using standard equipment. This of course depends on the environment, and can be reduced by metallic or water filled objects, to include humans between the transmitter and receiver.

Smooth acceleration and deceleration is performed using full voltage PWM (Pulse Width Modulation), meaning that it supplies full voltage motor but uses shorter or longer pulses so speed up or slow down a motor. DelTang uses a total of 512 steps (256 forward / 256 reverse) of speed control compared to 14 (7 forward / 7 reverse) on the LEGO® Power Functions system. To add to this, many controllers built, including the DelTang TX22 controller, containing the DelTang TX2 Transmitter Card have a inertia function, making very realistic starts and stops.

Motor power is driven by a 3 Amp H Bridge driver, this means that you can comfortably connect 2 LEGO® Power Function train motors to the receiver with no worry of overload. There are also other outputs that function by factory default for connecting Auto Forward and Reverse Lighting, alongside Aux outputs for sound card triggers, ditch lighting, de-couplers, etc.

Binding

With the 2.4gHz system, a receiver needs to be bound to a particular transmitter.  Once bound, the receiver remembers the settings and does not normally need to bound again – unless you want to bind it to a different transmitter.

An unlimited number of receivers can be bound to one transmitter, so several locomotives could be controlled by one transmitter allowing some quite impressive multi locomotive consists or assuming you only run one loco at a time, you only need one transmitter to control a whole fleet of locos. However, one of the clever feature of the Deltang TX22 transmitter is its ability to independently control several locomotives at the same time, independently using the Selecta system, this can be loosely compared to the channel function with in Power Functions, however, each DelTang TX22 controller is discrete, so if you have two transmitters, you could control 24 locomotives independently without controller interference.

Performance

I had the chance to give this system a good test during the recent 2018 NMRA show in Kansas City, I tested two DelTang RX65b (22) Receivers, using the RCtrains.co.uk RCT-Tx22 that contains a DelTang TX2 transmitter, driving Power Function train motor in Shawn Kelly’s Kansas City Southern MOC and a Power functions Large motor in my LNER Pacific A4 ‘Mallard’ MOC. I had bound the two receivers with a single controller and were assigned to Selecta channels 1 and 2. The receiver in the Mallard is a more permanent installation, as its coupled with a sound card, the receiver in the Kansas City Southern was a drop in that I had pre-wired with power functions connectors.

Performance was outstanding….

At least 70 meters, (250ft) of range, with zero disconnection issues, this was impressive, as were in a building that contained hundreds of layouts and commercial displays, flooded with cell phone activity. Compared to the Blue Tooth systems, this was the only one that worked reliably, the Blue Tooth systems, including the New LEGO® Powered Up system failed repeatedly, disconnecting constantly.

Final Verdict

The DelTang system is a well-designed, versatile control system that any slightly advance LEGO® train modeler should consider for a very advanced, simple use experience.

Pros

• Very Long Range
• Small foot print receiver
• High amperage motor driver
• Up to 7 Aux outputs
• Solid reliable radio connection

Cons

• Some wiring / soldering needed
• Initial cost of the equipment (up to $100)
• Not for the Purist.

Nerd Alert…… Advanced Information

‘Variants’ are simply ‘configurations’. Each variant is a different combination of settings to better match common needs. Although these are described as ‘car/train/boat’ any variant can be used for anything. All settings can be changed in a process called ‘programming’. F1-F3 (A/B/C) are programmed as P9-P11.

The receiver is built with 20v components and is rated for 3-18v operation.

‘P’ outputs are ‘pads’ with ‘logic’ type outputs. Pads are simply solder points for controlling external things. Logic outputs are either on or off (also known as high/low and 3.3v/0v in voltage terms). The action can be inverted so ‘On’ can mean 0v. P outputs are used to provide servo signals direct to the white/yellow lead on a servo. They can often directly control triggers on external sound cards. They are also used to drive leds but need a resistor to limit current to no more than 20mA.

‘F’ outputs are ‘buffered’ P outputs. The buffer is an N-channel fet. These provide a path to ground (0v) when on and are floating (disconnected) when off. If you are familiar with the term ‘open collector’ used with transistors, these are the same but with fets they are called ‘open drain’. Three F outputs exist on Rx65. They are labelled A, B and C. They are often used to control sound cards and lights.

The ‘H’ output is an H-Bridge. This is used to control the speed and direction of a brushed motor. This can also be referred to as an integrated ESC (Electronic Speed Controller). It has 256 step resolution in both directions (512 total). It controls speed with PWM which by default is set to its fastest (quietest) 16kHz setting. The H output can handle up to 3A current. This is measured with motor stalled. The main constraint with current is heat in the receiver. Higher currents may be possible if heat sinks are added or PWM frequency is reduced to 120Hz.

Some basic changes can be made with a paperclip by simply shorting two pads together (eg: with a paperclip):

1. Perform a ‘Hard reset’ (factory reset).
2. Change motor control between ‘low off’ and ‘center off’.
3. Enable/disable LVC (eg: when using Nicads, NiHMs, LiFe cells).
4. Enable/disable Selecta.
5. Enable/disable Cruise Control/Failsafe.
6. Enable/disable the Menu feature.

If the paper clip settings are not enough, you can program the Rx65 directly using a standard joystick style controller, to edit the 65 further options that receiver has.