FeatherTwo Data Sheet

Features

  • Compact Construction: 43mm x 75mm x 15mm
  • Available as a dual or single channel controller
  • Provides mixed bi-directional drive for two brushed motors (Dual)
  • Works from 8v to 24v (2-6S)
  • Drives 2 x 550 can motors, or one 775 can motor in single channel mode
  • Center motor braking to aid control
  • Approximately 80g with wires
  • 5V 0.5A regulated auxiliary power rail
  • Compatible with most standard receivers (Tested on Orange, Lemon, and Deltang receivers )

General Description

The FeatherTwo motor controller is a single board, dual motor controller that is specifically designed to control brushed drive motors in featherweight (13.6kg) fighting robots. They use 8 MOSFETs controlled by a PIC microcontroller, which decodes two servo signals from a radio receiver, and control the MOSFETs via a pulse width modulated signal.

To save weight and space, and help reduce cost, the controller has no metal heatsink. It instead uses ultra low resistance 240A rated MOSFETs in order to waste as little energy as possible as heat.

The board includes a 5 Volt, 1 amp voltage regulator which supplies power to the logic circuits as well as the receiver.

A status LED is fitted to the board near the motor wires to indicate when the board has power/signal. If the LED is off then there is no power to the board. If the LED is flashing then the board has power but no signal from the receiver. If the LED is on constantly then the board has both power and signal.

All boards are available with or without onboard signal mixing, and come with servo leads and wires for power and motors.

The controller is also available in single channel mode, where the board is reprogrammed and the two channels are wired in parallel to provide twice the current for higher power applications.


Maximum Ratings

Note: Permanent damage may occur if these ratings are exceeded. The performance of the device may degrade if used at or close to the maximum ratings for extended periods. Voltages below the minimum operating voltage will cause the device to function incorrectly or shutdown.

  • Maximum voltage: 30V
  • Minimum operating voltage 7.0V
  • Maximum 5v line current draw (@ 24V in) 1A

Recommended Operating Conditions

Note: These ratings have all been tested under the conditions specified in brackets.

  • Maximum Voltage: 24V (6 cell LiPo Battery)
  • Minimum Operating Voltage: 7.4V (2 cell LiPo Battery)
  • Continuous 5v line current draw (@ 24V in) 0.1A

Dual channel mode

  • Maximum continuous current draw per motor (24v, 3 mins) 30A
  • Maximum peak current draw per motor (24v, 5 sec) 80A

Single Channel Mode

  • Maximum continuous current draw per motor (24v, 3 mins) 60A
  • Maximum peak current draw per motor (24v, 5 sec) 160A

 


Installation Instructions

To install the FeatherTwo speed controller, the two motor wire pairs must be soldered to a pair of motors. The motor wires are the 4 black and red wires coming out of the side of the controller. The two red motor wires connect to one motor, and the two black motor wires go to the other motor as shown in figure 2. The FeatherTwo in dual channel mode will run one 550 or 600 can motor per channel, and in single channel mode will run one 775 or 900 can motor.

Once the motors are attached, plug the two servo connectors into a RC receiver. Some trial and error may be required to get the correct channels driving the correct motors, and in some cases, the connections on the motors may need to be reversed to get them running as expected. The trim on the transmitter will also need to be adjusted until neither motor is turning when the sticks are central. Be aware that the trim on the controller does change slightly with temperature, so it is advisable to check it is set correctly before each use.

In mixing mode, one channel controls steering, while the other controls forwards and backwards. Without mixing, the two inputs control each motor independently.
The FeatherTwo supplies 5v to power the receiver. A separate power supply should not be connected to the receiver as well. This means if another controller is used off the same receiver then the 5v lines of either the FeatherTwo or the other controller should be cut to avoid both attempting to power the receiver.

Before connecting a battery, check that no connections are shorting. The FeatherTwo has been designed to run with lithium polymer batteries. These will damage both themselves and the FeatherTwo if shorted through the controller. The recommended connectors to use with these controllers are XT60s or EC5s, though other similarly rated connectors may be used.

 

Fig 2. Recommended configuration using an Lemon Rx, 550 can motors and a 3S lipo