[
{
"id": "tagnav_tab",
"type": "tab",
"label": "DEXI Tag Navigation",
"disabled": false,
"info": "Tag-to-tag navigation as a flow.\n\nOne generic command node ('DEXI command → request' + 'DEXI services') calls both on-board services. The mission is a list of steps in the 'mission' function node. Start it from the RC hand-off (channel 7 to Offboard), the ENGAGE button, or START on the bench or in the sim.\n\nOn the aircraft: ARM hand-off runs once at deploy. The pilot takes off, hovers over a tag and switches to Offboard; tag_nav reports engaged, the mission runs and the aircraft lands. Leaving Offboard stops the mission."
},
{
"type": "function",
"name": "DEXI command → request",
"x": 560,
"y": 300,
"outputs": 1,
"func": "\n// msg.cmd = { command, parameter, timeout, north, east, down, yaw }\n// Tag commands go to tag_nav (parameter = tag id, north/east/down = body velocity);\n// everything else is a flight step for the offboard manager (parameter = meters or degrees).\nconst TAG_NAV = ['center_on_tag', 'hold_on_tag', 'fly_until_tag', 'wait_for_tag', 'wait_for_offboard'];\nconst c = msg.cmd || {};\nconst tag = TAG_NAV.includes(c.command);\nmsg.payload = tag ? {\n serviceName: '/dexi/tag_nav/command',\n serviceType: 'dexi_interfaces/srv/TagNavCommand',\n serviceRequest: { command: c.command, tag_id: Math.round(Number(c.parameter ?? -1)), hold_s: Number(c.hold_s ?? 0),\n forward: Number(c.north ?? 0), right: Number(c.east ?? 0), down: Number(c.down ?? 0),\n timeout: Number(c.timeout ?? 30) },\n} : {\n serviceName: '/dexi/flight/command',\n serviceType: 'dexi_interfaces/srv/FlightCommand',\n serviceRequest: { command: c.command, value: Number(c.parameter ?? 0), north: Number(c.north ?? 0),\n east: Number(c.east ?? 0), down: Number(c.down ?? 0), yaw: Number(c.yaw ?? 0),\n timeout: Number(c.timeout ?? 30) },\n};\nnode.status({ fill: 'blue', shape: 'dot', text: `${c.command} ${c.parameter ?? ''}` });\nreturn msg;",
"id": "tagnav_build",
"z": "tagnav_tab",
"wires": [
[
"tagnav_call"
]
]
},
{
"type": "ros2-service-call",
"name": "DEXI services",
"server": "27129f80a96ce509",
"x": 790,
"y": 300,
"id": "tagnav_call",
"z": "tagnav_tab",
"wires": [
[
"tagnav_route"
]
]
},
{
"type": "switch",
"name": "success?",
"property": "payload.success",
"propertyType": "msg",
"rules": [
{
"t": "true"
},
{
"t": "else"
}
],
"checkall": "false",
"repair": false,
"outputs": 2,
"x": 990,
"y": 300,
"id": "tagnav_route",
"z": "tagnav_tab",
"wires": [
[
"tagnav_dbg_ok",
"tagnav_gate_ok",
"tagnav_ui_resultfn",
"tagnav_rearm_after_land"
],
[
"tagnav_dbg_fail",
"tagnav_gate_fail",
"tagnav_ui_resultfn",
"tagnav_rearm_after_land"
]
]
},
{
"type": "debug",
"name": "step ok",
"active": true,
"tosidebar": true,
"complete": "payload.message",
"targetType": "msg",
"x": 1200,
"y": 260,
"id": "tagnav_dbg_ok",
"z": "tagnav_tab",
"wires": []
},
{
"type": "debug",
"name": "step FAILED",
"active": true,
"tosidebar": true,
"complete": "payload.message",
"targetType": "msg",
"x": 1200,
"y": 340,
"id": "tagnav_dbg_fail",
"z": "tagnav_tab",
"wires": []
},
{
"type": "function",
"name": "mission (steps as data)",
"x": 330,
"y": 300,
"outputs": 2,
"func": "\n// The route: tag ids in the order they are flown. The steps are built from it.\n// The first step centers on ROUTE[0], so hand over above that tag; use -1 to start on whichever tag is in view.\nconst ROUTE = [0, 1, 2, 3, 4]; // AVR 2026 flies [0, 1, 2, 3, 4, 5, 6]; a course with tags 0, 2, 4 flies [0, 2, 4]\nconst FWD = 0.25; // m/s transit speed; faster can outrun the tag detector in low light\n\n// Tag ids increase along the corridor, so a higher id is ahead (fly forward) and a lower id\n// is behind (fly backward). [0, 2, 4, 2, 0] works.\nconst STEPS = [{ command: 'center_on_tag', parameter: ROUTE[0], timeout: 25 }];\nfor (let k = 1; k < ROUTE.length; k++) {\n const tag = ROUTE[k], dir = Math.sign(tag - ROUTE[k - 1]) || 1;\n STEPS.push({ command: 'fly_until_tag', parameter: tag, timeout: 25, north: dir * FWD });\n STEPS.push({ command: 'center_on_tag', parameter: tag, timeout: 25 });\n}\nSTEPS.push({ command: 'land', parameter: 0, timeout: 30 });\n\nlet i = context.get('i');\nconst running = i !== undefined && i !== null && i < STEPS.length;\nif (msg.topic === 'start') {\n if (running) return null;\n i = 0;\n} else if (msg.topic === 'ok') {\n if (!running) return null;\n i = i + 1;\n} else if (msg.topic === 'failed' || msg.topic === 'land_now') {\n context.set('i', null);\n // Land only if the mission still has the aircraft. If the pilot took it back (left Offboard,\n // disengaged), a failed step means \"stood down\", and landing under a pilot is wrong.\n if (!flow.get('tagnav_go') && msg.topic !== 'land_now') { node.status({ fill: 'grey', shape: 'ring', text: 'failed: pilot has the aircraft' }); return null; }\n node.status({ fill: 'red', shape: 'ring', text: 'failed → land' });\n return [null, { cmd: { command: 'land', parameter: 0, timeout: 30 }, topic: 'land' }];\n} else if (msg.topic === 'reset') {\n context.set('i', null); node.status({}); return null;\n} else { return null; }\nif (i >= STEPS.length) { context.set('i', null); node.status({ fill: 'green', shape: 'dot', text: 'mission complete' }); return null; }\ncontext.set('i', i);\nnode.status({ fill: 'blue', shape: 'dot', text: `step ${i + 1}/${STEPS.length}: ${STEPS[i].command}` });\nreturn [{ cmd: STEPS[i], topic: 'step' }, null];",
"id": "tagnav_mission",
"z": "tagnav_tab",
"wires": [
[
"tagnav_build",
"tagnav_ui_stepfn"
],
[
"tagnav_build"
]
]
},
{
"type": "switch",
"name": "route result",
"property": "topic",
"propertyType": "msg",
"rules": [
{
"t": "eq",
"v": "step",
"vt": "str"
},
{
"t": "eq",
"v": "pilot_arm",
"vt": "str"
}
],
"checkall": "false",
"repair": false,
"outputs": 2,
"x": 1380,
"y": 200,
"id": "tagnav_gate_ok",
"z": "tagnav_tab",
"wires": [
[
"tagnav_ok"
],
[
"tagnav_pilot_takeoff"
]
]
},
{
"type": "switch",
"name": "mission step?",
"property": "topic",
"propertyType": "msg",
"rules": [
{
"t": "eq",
"v": "step",
"vt": "str"
}
],
"checkall": "false",
"repair": false,
"outputs": 1,
"x": 1380,
"y": 400,
"id": "tagnav_gate_fail",
"z": "tagnav_tab",
"wires": [
[
"tagnav_fail"
]
]
},
{
"type": "change",
"name": "→ ok",
"rules": [
{
"t": "set",
"p": "topic",
"pt": "msg",
"to": "ok",
"tot": "str"
}
],
"x": 1560,
"y": 200,
"id": "tagnav_ok",
"z": "tagnav_tab",
"wires": [
[
"tagnav_mission"
]
]
},
{
"type": "change",
"name": "→ failed",
"rules": [
{
"t": "set",
"p": "topic",
"pt": "msg",
"to": "failed",
"tot": "str"
}
],
"x": 1560,
"y": 400,
"id": "tagnav_fail",
"z": "tagnav_tab",
"wires": [
[
"tagnav_mission"
]
]
},
{
"type": "ros2-subscribe",
"name": "/dexi/tag_nav/status",
"server": "27129f80a96ce509",
"topicname": "/dexi/tag_nav/status",
"messagetype": "std_msgs/msg/String",
"x": 120,
"y": 120,
"id": "tagnav_sub",
"z": "tagnav_tab",
"wires": [
[
"tagnav_edge",
"tagnav_ui_statefn"
]
]
},
{
"type": "function",
"name": "engaged + OFFBOARD edge",
"x": 360,
"y": 120,
"outputs": 2,
"func": "// tag_nav publishes JSON at 5 Hz. Output 1: START on the rising edge of \"engaged, armed, in OFFBOARD\"\n// (RC channel 7 or the ENGAGE button), RESET on the falling edge. Output 2: re-arm the hand-off\n// stream whenever the aircraft disarms, because landing stops the manager's setpoint stream.\nlet st = {}; try { st = JSON.parse(msg.payload.data || '{}'); } catch (e) { return null; }\nconst go = st.engaged === true && st.nav_state === 14 && st.armed === true;\nconst was = context.get('go') || false;\ncontext.set('go', go); flow.set('tagnav_go', go); // the mission node reads this on a failure\nconst armed = st.armed === true, wasArmed = context.get('armed');\ncontext.set('armed', armed); flow.set('tagnav_armed', armed);\nlet out1 = null, out2 = null;\n// trace: last 40 samples the trigger saw (read with GET /context/node/tagnav_edge)\nconst tr = context.get('trace') || [];\ntr.push([new Date().toISOString().slice(11, 23), st.engaged ? 1 : 0, st.nav_state, st.armed ? 1 : 0, go ? 1 : 0]);\nwhile (tr.length > 40) tr.shift();\ncontext.set('trace', tr);\nif (go && !was) { node.status({ fill: 'green', shape: 'dot', text: 'hand-off → mission' }); out1 = { topic: 'start' }; }\nif (!go && was) { node.status({ fill: 'grey', shape: 'ring', text: 'stood down' }); out1 = { topic: 'reset' }; }\nif (wasArmed === true && !armed) out2 = { topic: 'rearm' };\nreturn [out1, out2];",
"id": "tagnav_edge",
"z": "tagnav_tab",
"wires": [
[
"tagnav_mission"
],
[
"tagnav_arm_fn"
]
]
},
{
"type": "inject",
"name": "ARM hand-off (runs once at deploy)",
"props": [
{
"p": "topic",
"vt": "str",
"v": "armhandoff"
}
],
"repeat": "",
"once": true,
"onceDelay": 5,
"topic": "armhandoff",
"x": 160,
"y": 460,
"id": "tagnav_inj_arm",
"z": "tagnav_tab",
"wires": [
[
"tagnav_arm_fn"
]
]
},
{
"type": "function",
"name": "start_setpoint_stream",
"x": 440,
"y": 460,
"outputs": 1,
"func": "\n// Stream-only heartbeat: the setpoint follows the aircraft until the pilot enters\n// Offboard, then latches where the aircraft is. Never commands Offboard itself.\nreturn { cmd: { command: 'start_setpoint_stream', parameter: 0, timeout: 5 }, topic: 'prep' };",
"id": "tagnav_arm_fn",
"z": "tagnav_tab",
"wires": [
[
"tagnav_build"
]
]
},
{
"type": "inject",
"name": "ENGAGE (button hand-off)",
"props": [
{
"p": "payload",
"v": "{\"data\":true}",
"vt": "json"
}
],
"repeat": "",
"once": false,
"payload": "{\"data\":true}",
"payloadType": "json",
"x": 140,
"y": 560,
"id": "tagnav_inj_engage",
"z": "tagnav_tab",
"wires": [
[
"tagnav_pub_engage",
"tagnav_engage_fn"
]
]
},
{
"type": "inject",
"name": "DISENGAGE",
"props": [
{
"p": "payload",
"v": "{\"data\":false}",
"vt": "json"
}
],
"repeat": "",
"once": false,
"payload": "{\"data\":false}",
"payloadType": "json",
"x": 110,
"y": 600,
"id": "tagnav_inj_disengage",
"z": "tagnav_tab",
"wires": [
[
"tagnav_pub_engage",
"tagnav_engage_fn"
]
]
},
{
"type": "ros2-publish",
"name": "/dexi/tag_nav/engage",
"server": "27129f80a96ce509",
"topicname": "/dexi/tag_nav/engage",
"messagetype": "std_msgs/msg/Bool",
"stampheader": false,
"x": 420,
"y": 580,
"id": "tagnav_pub_engage",
"z": "tagnav_tab",
"wires": []
},
{
"type": "function",
"name": "engage → switch_offboard_mode / disengage → switch_hold_mode",
"x": 460,
"y": 640,
"outputs": 1,
"func": "// The button does what the RC switch does: engage tag_nav AND put PX4 in Offboard.\n// Offboard needs setpoints flowing, so (re)start the stream first, then switch 600 ms later.\n// Disengage drops back to Hold so the pilot has a sane mode to fly out of.\nconst on = msg.payload && msg.payload.data === true;\nif (!on) return { cmd: { command: 'switch_hold_mode', parameter: 0, timeout: 5 }, topic: 'prep' };\nnode.send({ cmd: { command: 'start_setpoint_stream', parameter: 0, timeout: 5 }, topic: 'prep' });\nsetTimeout(() => node.send({ cmd: { command: 'switch_offboard_mode', parameter: 0, timeout: 5 }, topic: 'prep' }), 600);\nreturn null;",
"id": "tagnav_engage_fn",
"z": "tagnav_tab",
"wires": [
[
"tagnav_build"
]
]
},
{
"type": "inject",
"name": "PILOT: arm + takeoff 1.5 m (sim only)",
"props": [
{
"p": "topic",
"vt": "str",
"v": "pilot"
}
],
"repeat": "",
"once": false,
"topic": "pilot",
"x": 160,
"y": 700,
"id": "tagnav_inj_pilot",
"z": "tagnav_tab",
"wires": [
[
"tagnav_pilot_fn"
]
]
},
{
"type": "function",
"name": "arm (takeoff follows on success)",
"x": 440,
"y": 700,
"outputs": 1,
"func": "\n// Stand-in for the pilot in the simulator. On the aircraft the pilot takes off by hand.\n// Sends arm; the takeoff goes out only after PX4 confirms the arm (see 'then takeoff').\nreturn { cmd: { command: 'arm', parameter: 0, timeout: 10 }, topic: 'pilot_arm' };",
"id": "tagnav_pilot_fn",
"z": "tagnav_tab",
"wires": [
[
"tagnav_build"
]
]
},
{
"type": "inject",
"name": "START mission now (bench/sim)",
"props": [
{
"p": "topic",
"vt": "str",
"v": "start"
}
],
"repeat": "",
"once": false,
"topic": "start",
"x": 140,
"y": 240,
"id": "tagnav_inj_start",
"z": "tagnav_tab",
"wires": [
[
"tagnav_mission"
]
]
},
{
"type": "inject",
"name": "RESET",
"props": [
{
"p": "topic",
"vt": "str",
"v": "reset"
}
],
"repeat": "",
"once": false,
"topic": "reset",
"x": 100,
"y": 360,
"id": "tagnav_inj_reset",
"z": "tagnav_tab",
"wires": [
[
"tagnav_mission"
]
]
},
{
"type": "inject",
"name": "LAND now",
"props": [
{
"p": "topic",
"vt": "str",
"v": "land_now"
}
],
"repeat": "",
"once": false,
"topic": "land_now",
"x": 100,
"y": 400,
"id": "tagnav_inj_land",
"z": "tagnav_tab",
"wires": [
[
"tagnav_mission"
]
]
},
{
"id": "tagnav_pilot_takeoff",
"type": "function",
"z": "tagnav_tab",
"name": "then takeoff 1.5 m",
"x": 1560,
"y": 120,
"outputs": 1,
"func": "return { cmd: { command: 'takeoff', parameter: 1.5, timeout: 30 }, topic: 'pilot' };",
"wires": [
[
"tagnav_build"
]
]
},
{
"id": "tagnav_ui_base",
"type": "ui_base",
"theme": {
"name": "theme-dark",
"lightTheme": {
"default": "#0094CE",
"baseColor": "#0094CE",
"baseFont": "-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif",
"edited": true,
"reset": false
},
"darkTheme": {
"default": "#097479",
"baseColor": "#2A9D8F",
"baseFont": "-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif",
"edited": true,
"reset": false
},
"themeState": {
"base-color": {
"default": "#097479",
"value": "#2A9D8F",
"edited": true
},
"page-titlebar-backgroundColor": {
"value": "#2A9D8F",
"edited": false
},
"page-backgroundColor": {
"value": "#0b0f14",
"edited": false
},
"page-sidebar-backgroundColor": {
"value": "#000000",
"edited": false
},
"group-textColor": {
"value": "#5fd4c7",
"edited": false
},
"group-borderColor": {
"value": "#1f2a30",
"edited": false
},
"group-backgroundColor": {
"value": "#10161c",
"edited": false
},
"widget-textColor": {
"value": "#eeeeee",
"edited": false
},
"widget-backgroundColor": {
"value": "#2A9D8F",
"edited": false
},
"widget-borderColor": {
"value": "#10161c",
"edited": false
},
"base-font": {
"value": "-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif"
}
},
"angularTheme": {
"primary": "indigo",
"accents": "blue",
"warn": "red",
"background": "grey",
"palette": "light"
}
},
"site": {
"name": "DEXI",
"hideToolbar": "false",
"allowSwipe": "false",
"lockMenu": "false",
"allowTempTheme": "true",
"dateFormat": "M/D/YYYY",
"sizes": {
"sx": 48,
"sy": 48,
"gx": 6,
"gy": 6,
"cx": 6,
"cy": 6,
"px": 0,
"py": 0
}
}
},
{
"id": "tagnav_ui_tab",
"type": "ui_tab",
"name": "DEXI April Tag Navigation",
"icon": "dashboard",
"disabled": false,
"hidden": false
},
{
"id": "tagnav_ui_cam",
"type": "ui_group",
"name": "Downward camera",
"tab": "tagnav_ui_tab",
"order": 1,
"disp": true,
"width": "12",
"collapse": false,
"className": ""
},
{
"id": "tagnav_ui_grp",
"type": "ui_group",
"name": "Mission",
"tab": "tagnav_ui_tab",
"order": 2,
"disp": true,
"width": "12",
"collapse": false,
"className": ""
},
{
"id": "tagnav_ui_camera",
"type": "ui_template",
"z": "tagnav_tab",
"group": "tagnav_ui_cam",
"name": "camera",
"order": 1,
"width": "12",
"height": "9",
"format": "![\"\"]()
\n
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