Map TI eZ430-Chronos watch accelerometer X/Y tilt to ARC servos for intuitive, Wii-Remote-style control of servo positions.
How to add the Ez430-Chronos Wrist Watch robot skill
- Load the most recent release of ARC (Get ARC).
- Press the Project tab from the top menu bar in ARC.
- Press Add Robot Skill from the button ribbon bar in ARC.
- Choose the Misc category tab.
- Press the Ez430-Chronos Wrist Watch icon to add the robot skill to your project.
Don't have a robot yet?
Follow the Getting Started Guide to build a robot and use the Ez430-Chronos Wrist Watch robot skill.
How to use the Ez430-Chronos Wrist Watch robot skill
The Texas Instruments eZ430-Chronos Programmable Wrist Watch is a wearable device that includes sensors such as an accelerometer (a motion/tilt sensor). In Synthiam ARC, the eZ430-Chronos Wrist Watch robot skill lets you use that accelerometer to control your robot by moving your wrist.
What this skill can do
- Read accelerometer data from the watch (tilt/motion).
- Map the watch’s X-axis and Y-axis tilt to servo positions in ARC.
- Let you control a robot arm, camera mount (pan/tilt), or other servo-driven parts by simply moving your wrist.
What you need before you start
- Synthiam ARC installed and running.
- A TI eZ430-Chronos watch and its USB RF access point/dongle (the wireless receiver that plugs into your PC).
- (Optional but common) A robot controller connected to ARC (such as an EZB or other supported servo controller) with at least one servo configured.
Key concepts (plain-English)
- X-axis: Typically left-to-right tilt of your wrist (like rolling your hand side to side).
- Y-axis: Typically forward-to-back tilt (like pointing your hand up/down).
- Servo position: A servo’s target angle/value (for example, 1–180 degrees depending on your configuration).
- Mapping: Converting sensor values (tilt) into servo positions (movement).
Basic setup overview
-
Connect the watch receiver
Plug the eZ430-Chronos USB RF dongle into your computer. -
Start ARC and add the skill
In ARC, open Project → Add Skill (or Skill Store) and add the eZ430-Chronos Wrist Watch skill. -
Link/pair the watch
Ensure the watch is communicating with the USB receiver (follow your Chronos pairing/link steps if needed). Once linked, ARC should begin receiving accelerometer data. -
Choose what you want to control
Decide which servo(s) you want to move. A common beginner example is:- X-axis tilt controls a pan servo (left/right)
- Y-axis tilt controls a tilt servo (up/down)
Assigning the accelerometer to servos (typical use)
ARC can take the watch’s accelerometer readings and translate them into servo positions. When you tilt your wrist, ARC updates the servo position to match your movement.
- Assign the X-axis to a servo you want to move left/right (for example, a camera pan servo).
- Assign the Y-axis to a servo you want to move up/down (for example, a camera tilt servo).
- Adjust ranges (if available in the skill) so small wrist movements don’t cause extreme servo movement.
Example beginner project ideas
Pan/Tilt Camera Mount
Use X and Y tilt to control a two-servo camera mount so you can look around by moving your wrist.
Robot Arm Joint Control
Assign one axis to an arm joint servo (like a wrist or elbow). Start with slow movement and small ranges.
Troubleshooting
- Confirm the USB RF dongle is plugged in directly (try another USB port).
- Make sure the watch is linked/paired to the dongle.
- Close other software that might be using the Chronos receiver.
- Restart ARC after connecting the dongle.
- Reduce the mapping range so tilt changes translate into smaller servo changes.
- Add smoothing (if the skill provides it) to reduce jitter.
- Check servo power—weak power supplies can cause erratic movement.
- Enable axis inversion/reverse if the skill includes that option.
- Swap or reverse the min/max values used for the servo mapping.
- Physically re-mounting the watch orientation can also change perceived directions.
Safety and best practices
- Start with slow servo speeds and small ranges to prevent sudden movements.
- Keep hands and cables away from moving parts while testing.
- If controlling multiple servos, test one axis at a time first (X only, then Y).
Once the watch is linked and the axes are mapped, you can control your robot naturally by moving your wrist—making the eZ430-Chronos a simple, beginner-friendly motion controller inside ARC.
