Notice: 
  - This tutorial follows the 2DOF Hexapod assembly guide. Make sure all servos and other connections are set up as detailed there.

Required Hardware:
  - Any Lynxmotion 2 DOF Hexapod
  - SSC-32
  - Bot Board / BASIC Atom Pro 28
  - PS2 Cable
  - PS2 Wireless Controller (Not included in combo kit)
  - Sharp GP2D12 Sensor (Optional, see text)

Required Software:
  - LynxTerm (free download)
  - Basic Micro Studio ver 2.0.0.0
  - Basic Atom Pro Hexapod Programs:
   > h2prog01.zip PS2.
   > h2prog02.zip PS2.
   > h2prog03.zip PS2.
   > h2prog04.zip Autonomous!

Goal:
  - Install, program, and test the electronics to operate a Hexapod 2 remotely from a Lynxmotion wireless controller or autonomously using sensors.

Connect the serial data cable to the PC's serial port. This can be recognized by having 9 pins that stick out. Connect the other end of the serial data cable to the SSC-32's DB9 port. 

Note, if your computer does not have a native serial port, you can add one, or you can also use a high quality USB to Serial adapter such as one made by FTDI. If you are using an FTDI adapter cable, please install the VCP (Virtual Com Port) driver and change the "latency" property to its minimum.

Note, the LED on the SSC-32 is not a power indicator but a status indicator. Its job is to light up on power up showing the SSC-32 is 95% functional. After it receives a serial command it will turn off, and from there on it will blink when it receives data. This will happen even if the data is not formatted correctly. The LED on the Bot Board II is a simple power indicator.

Figure 2.

Click the All=1500 button at the bottom of the program and the legs should respond by quickly moving to a position near centered. If the robot was constructed properly, the legs will be horizontal and perpendicular to the body. If the legs are more than 15° off you may need to remove the output horn, rotate it, and reinstall it. The next step is to align the servos in software to be perfectly aligned. 

Figure 3.

Since no servo is perfect, you will need to set offsets to center each servo. Use the Offset tool under Servo Quick Test. Click on "Read" to load any previous offset settings. Select the servo on the Hexapod diagram and adjust the offset slider to fine-tune the leg alignment. Do this for all twelve servos. When completed, click on "Write" to save your offsets to the SSC-32 EEPROM. 

Refer to Figures 4-2 and 4-3 for how each servo should be aligned. 

Figure 4-1.

Figure 4-2.

Figure 4-3.

Schematic.
Double check your connections against the schematic below. Be sure that red wires go to positive (+) and black wires go to negative (-). Also be sure that your jumpers are connected the exact same way as detailed below. Note: Your PS2 cable may not match up with Schematic 1. Refer to Schematic 2 for accurate connection information.

  Schematic 1.

Schematic 2.

Both modes offer additional control of leg trajectory for the alternating tripod gait. This refers to the vertical and horizontal motion that the foot goes through during the walking gait. Pressing /\, O (default), X, or [] changes how the foot is lifted and the stride motion. 

If the robot is driven toward an obstacle, after a threshold is reached the forward joystick position is ignored. However, you can still reverse direction. The controller will also vibrate proportionally in relation to the distance from the obstacle. The Sharp sensor can be enabled or disabled with the Start button.

You may notice that there are no commands to change the height of the robot's body in the default program. In order to take full advantage of the mechanical advantage legs, they need to remain at their highest point. 

Figure 6.

The exact angle of the sensors isn't critical, but will affect the robot's behavior. Experimentation is encouraged.

The values for the L* and R* textboxes will control the positions the legs are moved to in the sequence. You can fine-tune these values to your mechanical leg arrangement with the same Servo Quick Test. Just adjust the position slider instead of the offset slider. 
 

You have complete control over all aspects of the tripod gait. Adjust either XL or XR lower to do gradual turns. Setting XL and XR to opposite directions will cause the robot to turn in place. Reverse values of XL and XR will cause the robot to walk backwards. Moving a slider is the same as typing from the terminal or sending the command from a microcontroller. For example, moving XS to 50% is the same as sending "XS50". Once the commands are sent, the robot will continue to walk until it receives XS = 0. If you are using a host microcontroller to send commands, it will be free to do any timing-intensive tasks without worrying about any of the walking process.

Figure 9.