Step Recording

Missions are sequences of motion steps stored as files in the ESP32’s flash storage. You can create missions, add steps by position or JSON command, edit individual steps, and play them back with repeat counts.

Mission Lifecycle

graph TD
    A[Create Mission] -->|T:220| B[Empty Mission File]
    B --> C{Add Steps}
    C -->|T:222| D[Append JSON Step]
    C -->|T:223| E[Append Feedback Step]
    C -->|T:224| F[Append Delay]
    D & E & F --> G[Mission Ready]
    G -->|T:242| H[Play Mission]
    G -->|T:221| I[View Contents]
    G -->|T:241| J[Move to Step]

Creating a Mission

{"T":220,"name":"pick_place","intro":"Pick and place demo sequence"}

This creates a new file in flash with the given name and description.

Adding Steps

From JSON Command

Append a motion command as a step:

{"T":222,"name":"pick_place","step":"{\"T\":104,\"x\":235,\"y\":0,\"z\":234,\"t\":3.14,\"spd\":0.25}"}

Any valid JSON command can be embedded as a step — including gripper commands, light controls, or delays.

From Current Position

Record the arm’s current position as a step (uses feedback data):

{"T":223,"name":"pick_place","spd":0.25}

Tip

This is the easiest way to record missions — manually position the arm (using the web interface or lead-through teaching), then capture each pose with T:223.

Add a Delay

Insert a timed pause between steps:

{"T":224,"name":"pick_place","delay":3000}

The delay is in milliseconds.

Editing Steps

Insert at Position

Insert JSON command at step 3:

{"T":225,"name":"pick_place","stepNum":3,"step":"{\"T\":104,\"x\":235,\"y\":0,\"z\":234,\"t\":3.14,\"spd\":0.25}"}

Insert from feedback at step 3:

{"T":226,"name":"pick_place","stepNum":3,"spd":0.25}

Insert delay at step 3:

{"T":227,"stepNum":3,"delay":3000}

Replace a Step

Replace with JSON command:

{"T":228,"name":"pick_place","stepNum":3,"step":"{\"T\":114,\"led\":255}"}

Replace with feedback position:

{"T":229,"name":"pick_place","stepNum":3,"spd":0.25}

Replace with delay:

{"T":230,"name":"pick_place","stepNum":3,"delay":3000}

Delete a Step

{"T":231,"name":"pick_place","stepNum":3}

Reviewing a Mission

View All Steps

{"T":221,"name":"pick_place"}

Returns the full content of the mission file, including all steps with their indices.

Move to a Specific Step

Navigate the arm to a particular step’s position without playing the full sequence:

{"T":241,"name":"pick_place","stepNum":3}

Playing a Mission

Fixed Repeat Count

{"T":242,"name":"pick_place","times":3}

Loop Forever

Set times to -1 for continuous playback:

{"T":242,"name":"pick_place","times":-1}

Caution

During infinite loop playback, send {"T":0} (emergency stop) to halt execution.

Boot Mission

You can configure a mission to run automatically when the arm powers on:

Check current boot mission:

{"T":602}

Clear boot mission:

{"T":603}

Command Summary

T-Code	Command	Description
220	Create mission	New mission file with name and intro
221	View mission	Read all steps
222	Append JSON step	Add command string as step
223	Append feedback step	Record current position
224	Append delay	Add timed pause
225	Insert JSON step	Insert command at position
226	Insert feedback step	Insert current position at index
227	Insert delay	Insert pause at position
228	Replace with JSON	Overwrite step with command
229	Replace with feedback	Overwrite step with current position
230	Replace with delay	Overwrite step with pause
231	Delete step	Remove step at index
241	Move to step	Go to step position
242	Play mission	Execute with repeat count

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Mission system reference from firmware source json_cmd.h and Waveshare Wiki.