Tx20 Transmitter Kit

This kit includes the core components to make a Tx20 transmitter.
Tx20 is a compact wireless transmitter intended to control model railway train engines.
It has controls for Speed, Direction, Sounds, Coupling and Lights (depending on how used).


1Small plastic box
13-way Direction toggle switch
1On/Off pushbutton with Led
1Bind pushbutton
2Function pushbutton
110k pot 300° rotation with center click (detent)
1Large Speed knob
1470R resistorYellow-Violet-Black-Black-Brown
110k resistorBrown-Black-Orange-Brown
218k resistorBrown-Grey-Black-Red-Brown
2100k resistorBrown-Black-Black-Orange-Brown
1PP3 plug
50mm30mm heatshrink for Tx2
1Plastic sheet for battery compartment
1Wiring diagram
1Drill template
1This page (www.DelTang.co.uk/tx20-kit.htm)

PP3 9v battery, hookup wire.
Solder, Iron, Multimeter, Glue, heat-shrink tubing, Drills, Files, Knife, Screwdrivers etc.

Tx20 circuit

Tx20 layout

ASSEMBLY EXAMPLE (click to enlarge):

1. The circuit diagram shows the required connections.
2. The 'Tx2' radio module is powered with 9v. Tx2 has an on-board regulator which provides a 3.1v reference voltage to the other components.
3. The 2 longer wires in the middle of the on/off switch are 'Led2'. The shorter of those is marked '-' and goes to negative.
4. The on/off switch has an anti-rotation ridge that makes its diameter larger at that point. File a notch in the box to avoid crushing the switch.
5. The pot has a protrusion to prevent body rotation. This is not needed and can be cut off with side-cutters or hacksaw.
6. The Tx2 module can be protected with with the heatshrink covering provided.

The motor control pot (Ch1) has a 'click' at the center position. When Throttle is used 'center off' it needs to center accurately so that the 'click' on the Tx matches the 'off' position in DelTang receivers. Calibration is done using the Bind button while Tx20 is on. After pressing the Bind button for ~20s Ch1 is calibrated.

1. Switch Tx20 on. The led will come on.
2. Rotate the Inertia button fully anti-clockwise (left) so it has no effect on Throttle.
3. Center the Motor pot.
4. Press and hold the Bind button for ~20s until the led goes off. Ch1 should now be calibrated.
5. Release the Bind button. The led will come back on.

Home Videos About Buy Email