LSS - Adapter Board

Version 49.3 by Brahim Daouas on 2018/05/07 15:08

Description

The Lynxmotion Smart Servo (LSS) Adapter Board is a simple to use interface to configure/control the Lynxmotion Smart Servos. The board also provides power distribution and includes over-current protection using re-settable 3A (5A trip) fuses for each of its six outputs. It can be powered from a battery through the on-board male XT60 connector, or with a wall adapter (using an XT60 to barrel adapter). There are many ways to interface with this board, as described below.

Features

Control LSS Smart Servos via 6x connectors
On-board XBee Socket
Arduino stackable shield compatible
Selectable control method :USB, Arduino or XBee
Raspberry Pi B+/2/3 mounting compatibility
Over-current protection (via re-settable fuse) for each connector
XT60 Connector for power input
Automatic logic power selection (USB/External)

Specifications

3A (max) continuous per channel (trips at 5A)
Built-in USB to serial (FTDI Virtual COM Port chip)
Built-in 5V regulator
USB Micro connector
Dimensions : 64 x 64 x 15mm

Communication / Control

Micro USB: ex: computer, laptop, Raspberry Pi
Arduino shield compatible (use female to male 2.54mm (0.1") spaced pins at least 14mm long)
Microcontroller or FPGA control via Tx, Rx, GND pins headers
Wireless module with XBee footprint (Bluetooth Bee, WiFi Bee etc.)

USB to Serial Drivers

The LSS Adapter uses the FT232RL FTDI chip to convert USB to UART. Most operating systems will automatically detect the FTDI chip and install the correct VCP drivers. In case this is not done automatically, VCP drivers for the FT232RL chip can be downloaded through this link (choose the VCP driver which corresponds to your operating system).

Wiring

The LSS adapter allows up to six sets of servos to be connected to the same bus and share the same power supply and greatly simplifies wiring for more complex robots. For example the servos of an 18 degree of freedom hexapod robot can be split into groups of three.

LSS Adapter - Servo Wiring.png

Power
	The FTDI chip can be powered through the on-board USB or with an external power supply through the XT60 connector. The 5V from the USB will only power the FTDI chip and the XBee compatible wireless module (if inserted) and won't power the servos. To power the servos, an external power supply (6V to 12V) is needed (more information in the "LSS - Electrical" section). If both USB and external power supply are connected at the same time, the external power supply will be automatically selected to power the FTDI chip and XBee module if it's higher than 7V. The external power supply can be a battery or an AC-to-DC wall adapter with the appropriate barrel to XT60 converter (more information in "LSS - Electrical" section). The adapter can operate on an external supply from 7V to 25V DC. Note however that the LSS servos are intended to operate at between 6V and 12V. If the board is supplied with less than 7V, the 5V pins from the internal regulator may supply less than 5V and the adapter may not function properly. Using more than 25V may damage the 5V regulator. Arduino : In the case where the LSS Adapter is stacked on top of an Arduino Board, the Arduino board can be powered from the Vin pin which is directly connected to the external supply voltage of the LSS Adapter. If the Arduino Board is powered separately via another external power supply (ex barrel connector), the “Vin cut” solder bridge on the bottom of the LSS Adapter Board needs to be cut. The ‘“Vin cut” solder bridge doesn’t need to be cut if the Arduino is powered through USB. Raspberry Pi : It is recommended to power the Raspberry Pi separately using an appropriate power supply. This Raspberry Pi Power Supply 5V 3A can be used to power the Raspberry Pi. Other MCUs : The 5V or the 3.3V outputs can be used to power other MCUs/Controllers. The 5V supply can provide up to 1A and the 3.3V can provide up to 500mA.
(1) : XT60 Connector for 6V-12V external power input (more information in "LSS - Electrical" section). (2) : LSS servo connectors

Configurations

Using the LSS Adapter Board is fairly simple and user-friendly. The configuration switch on the board allows the user to select one of the following control methods

Arduino
	To use the LSS Adapter Board with an Arduino Board, the switch should be on position 1. This configuration allows controlling LSS actuators from an Arduino Board and can be used to build autonomous or semi-autonomous robots. When Arduino (position 1) is selected on the communication switch, the Arduino Rx (digital 0) is connected to the LSS actuator's Tx and Arduino Tx (digital 1) is connected to the LSS actuator's Rx. This way, the Arduino communicates with the LSS actuator through the LSS Adapter Board. By default, the Arduino is powered through the LSS Adapter Board, if the Arduino is powered separately, cut the solder jumper "Vin cut" on the bottom of the LSS Adapter Board.
	The LSS Adapter is shield compatible. Therefore it can be stacked on top of an Arduino Board using the included Arduino stacking headers or male-to-male stacking pins.
XBee / Bluetooth Bee / WiFi Bee / RF Bee
	To use the LSS Adapter Board with an XBee Module, the switch should be on position 2. This configuration allows controlling LSS actuators wirelessly with an XBee/Bluetooth Bee/Wifi Bee module. When XBee (position 2) is selected on the communication switch, the XBee Rx is connected to the LSS actuator's Tx and the XBee Tx is connected to the LSS actuator's Rx. This way, the Bee module communicates directly with the LSS actuator through the adapter. Plus, when the configuration switch is on position 2, the LSS Tx is connected to the Arduino pin 8 and the LSS Rx is connected to the Arduino pin 9 allowing to use Software Serial
	The XBee Rx pin and Tx pins are connected to the Arduino's pin 8 and 9 respectively. Therefore, the LSS Adapter Board can be also used as a USB XBee explorer board to configure the XBee module through USB. To use the LSS Adapter Board as a USB XBee explorer : Stack the XBee module on the XBee socket on top of the LSS Adapter. Select the USB configuration by turning the switch in position 3 Connect the Arduino pin 8 (XBee Rx) to the LSS Servo Rx pin Connect the Arduino pin 9 (XBee Tx) to the LSS Servo Tx pin
PC USB or Raspberry Pi
	To use the LSS Adapter Board with a Raspberry Pi or a standard computer / laptop through USB, the switch should be on position 3. This configuration allows controlling LSS actuators by sending serial commands from a computer or a Raspberry Pi via USB. When USB (position 3) is selected on the communication switch, the FTDI Rx is connected to the LSS actuator's Tx and FTDI Tx is connected to the LSS actuator's Rx. The mounting holes for the LSS Adapter are compatible with the Raspberry Pi 2 / 3.
Note : A configuration can be chosen by pointing the arrow of the switch to the upper half circle of the switch or to the bottom one. For example, if USB configuration needs to be chosen, it doesn't matter which number "3" the arrow of the switch is pointing to. Both will work normally. Others
	The LSS Adapter Board has the Tx and Rx pins broken-out to be interfaced with other devices that have a UART Serial interface. It also has a 3.3V (500mA maximum) and 5V (1.5A maximum) output pins :