Aux Output

The Aux Output is similar to the other four light outputs: it uses a 2-pin JST-PH connector and can drive an LED with the same caveats that apply to the light ports. As with the L1 and L2 ports, there are functions to turn the Aux Output on, off, or toggle; but you can also do more including flash, blink, or vary the brightness of a light.

The Aux Output also has a flyback diode installed. A “flyback” diode protects circuitry from reverse voltage spikes that occur when an inductive load is turned off. The two types of inductive loads we may be interested in controlling from the Aux output are relays and small motors.


Use a 5 volt relay on the Aux Output when you want to drive some high current device. No special circuitry is needed, just wire the coil of the relay to the Aux Output and use the on, off, or toggle functions to control the relay.


You can also attach a small motor directly to the Aux Output port. It will be driven by the TCB's onboard 5 volt circuit, which theoretically can supply up to 3 amps total, but remember, this is 3 amps for all 5 volt devices plugged into the TCB. The MOSFET used on the Aux Output can easily handle 3 amps, but if you attach a motor that draws 3 amps you will have no current left for running the onboard IC or anything else. Also the JST-PH connector is itself only rated to carry 2 amps. Keep these limitations in mind if you decide to attach a motor to the Aux Output.

Note - in addition to being turned on or off, the Aux Output can also be “dimmed” as you will read below. When a motor is attached to the Aux Output and you adjust the dim setting, you will actually be adjusting the speed of the motor. In other words you can use this output as a small, unidirectional ESC.

Note - need an even higher current, unidirectional ESC? You can choose manual control of the Smoker output and use it as a general purpose motor controller. It can handle much more current than the Aux Output and will be driven at the same voltage as your source battery (instead of 5 volts for the Aux output).

Other Aux Output Functions

Dim and Preset Dim

On the Lights & IO tab of the OP Config program, you can specify a preset dim level that you can then assign a trigger to. Triggering the Aux Output - Preset Dim Level function is similar to turning the output On, only it will turned on to the preset dim level rather than full brightness.

Or, if you have an analog trigger source (such as a rotating knob on your radio transmitter), you can vary the dim level on the fly by assigning that channel to the Aux Output - Set Level function. By varying the dim level you can change the brightness of a light or the speed of a motor. Note the motor can only turn in one direction (to reverse direction reverse the motor's wires). This is not intended to replace the primary motor options for driving your model! As mentioned above, the Aux Output port is low current and only 5 volts.


The Aux Output can be set to flash (blink once). The length of time of the flash is specified on the Lights & IO tab of the OP Config program, from 1/1000th of a second to 5 seconds.

There are two ways to cause a flash to occur. You can check the “Auto Flash with Cannon” option in OP Config on the Lights & IO tab. Now any LED connected to the Aux Output will flash automatically when the cannon is fired. This will be the most common usage for those with LED muzzle lights. (But if you want to use a Taigen high-intensity flash unit the TCB has a dedicated port for that, see here.)

Or you can control the flash manually whenever you want, by assigning any trigger to the Aux Output - Flash function.

The Aux Output also has an Inverse Flash function that holds the output high until the flash occurs, at which point the output is brought low (to ground) temporarily. This is not very useful for controlling an actual light, but it can be used as a logic input into external devices that interpret a pin held low as a button press (for example, inexpensive WAV/MP3 players).

Two functions can be used to blink the Aux Ouput - Aux Output - Blink and Aux Output - Toggle Blink. Each blink consists of an on time and an off time, both times can be adjusted precisely on the Lights & IO tab of the OP Config program. Among other things, this would be useful for creating a second machine gun light.

Revolving Light

This is another effect you can trigger on the aux output, the functions are Aux Output - Revolving Light and Aux Output - Toggle Revolving Light. This setting attempts to simulate the effect of a rotating light, which it does entirely by changing the brightness of the light in a certain pattern. Frankly it doesn't look very realistic, but it's there if you want to play with it.

wiki/tcb/tcbinstall/special_aux_output.txt · Last modified: 2017/07/24 02:28 by opadmin