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Vorpal The Hexapod Trim Mode Guide

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Trim Mode is a special gamepad mode that allows you to finely adjust the servo motors' default positions. This is needed because the servo horns that come with your servos only have 22 positions available for installation. This means the closest you can come to having perfectly aligned servos is plus or minus 8 degrees.

Trimming your servos will ensure the robot stands straight, it will help the robot to walk in a straight line (at least on smooth surfaces), and it will ensure all the servos are equally contributing to supporting the robot. This will increase the servo life by ensuring no servo is carrying more load than it's supposed to.

The trimming process only takes about 5 minutes, and it only has to be done once after assembly (or after swapping a servo). Trim positions are stored in the robot's EEPROM (sort of like a very tiny flash drive inside the Arduino Nano) so turning the robot off won't erase trim settings.

Firmware Version Required for Trim Mode

Trim mode is a new feature in the Vorpal Hexapod V2 and later versions of the software. This software is standard in all our kits ordered after July 16, 2018. If you ordered a kit from us on or after that date, you should have the V2 firmware. If you ordered a kit from us before that date, you do not have V2 firmware.

For instructions on updating your firmware to V2, see Vorpal The Hexapod Arduino Setup Guide

Putting the Gamepad in Trim Mode

Trim mode is invoked by booting the gamepad while simultaneously holding down the W1 button. The exact steps are:

  1. Turn off the gamepad.
  2. Hold down the W1 button, and keep holding it.
  3. Turn on the gamepad.
  4. Wait 5 seconds or so, then release W1. You should now be in Trim mode.

To make sure you really are in Trim mode, press the R2 button on the gamepad. This should cause the robot's legs to toggle between "ADJ" mode positions and "STOP" mode positions.

Trim Mode Functions

In Trim Mode the gamepad buttons have special meanings, as listed below.

DPAD Trim Functions

Vorpal The Hexapod Robot
  • Special (the button all the way up top) moves to the next leg. The leg raises and lowers for a moment to give you visual confirmation of which leg you are adjusting.
  • forward, backward: these buttons adjust the knee position, forward=higher, backward=lower
  • left, right: these buttons adjust the hip. It's best to hold the robot so you're looking at the bottom side, this way you can see the alignment of the servo horns. In this position, the "left" button moves the servo horn counter-clockwise and the "right" button moves it clockwise. If the hip being adjusted is pointing up (the 12 O'clock position) then the left and right buttons will work in an intuitive fashion.

4x4 Matrix Trim Functions

Vorpal The Hexapod Robot

Only the "R" row of buttons is used. The other buttons do nothing in trim mode.

  • R1 (Save): Holding this button down for 2 seconds saves the current trim settings into EEPROM. Note: nothing is saved until you hit this button!
  • R2 (Pose): This button toggles the pose of the robot between standing pose and adjust mode pose. Normally you want to be in adjust mode pose to set the trims, but you can use this button to confirm that the robot is standing nicely on the table. Each time you tap it, the pose toggles.
  • R3 (Show Untrimmed): If you hold this button down and keep holding it, the robot will show you what all the untrimmed positions look like. Releasing this button goes back to showing you trimmed positions.
  • R4 (Erase Trims): This button has to be held down for more than 1 second, and it resets all current trim values to 0 trim. This lets you just "start over". NOTE: This does not save the erased trims back to EEPROM! You still need to hit R1 to save the trims if you really want to wipe them back to all 0 trims.

Exiting Trim Mode

When you are done trimming, simply reboot the gamepad without holding down W1 and it will function normally again.

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