Loading the API
The DragonFly serves a JavaScript library from its own web server. Load it into your page with a script tag, no download or installation needed:
<script src="http://dragonfly/code.js"></script>
Replace dragonfly with the device hostname or IP address if the default hostname doesn't resolve. This file is served directly by the controller. Once loaded, the API functions and data arrays are available in the page's global scope.
Same-network only. The API is designed for pages served on the local observatory network. Browser security restrictions prevent loading it from external hosts, and there is no authentication layer. Ensure your observatory network is not exposed to the public internet.
Reading sensor values—sn[]
The sn[] array contains the current reading of each sensor input. There are 8 sensor channels, indexed 0–7:
-- Read sensor 0: var reading = sn[0]; -- Values are integers, 0–1023 (analog range). -- Digital interpretation: below 512 = off, 512 or above = on.
| Property | Type | Description |
|---|---|---|
| sn[0]…sn[7] | Integer 0–1023 | Sensor input reading. Analog sensors return a value across the full range. Digital inputs read near 0 (off) or near 1023 (on). Values below 512 are treated as digital "off". |
Reading relay states—rl[]
The rl[] array contains the current state of each relay output. There are 8 relays, indexed 0–7:
-- Read relay 0 state: var roofOpen = rl[0]; -- true if energised, false if open
| Property | Type | Description |
|---|---|---|
| rl[0]…rl[7] | Boolean | Current relay state. true = relay is closed (energised). false = relay is open. |
Sending relay commands—dflyDo()
Use dflyDo() to send a command to a relay:
dflyDo( address, command, relay, timing );
| Parameter | Type | Description |
|---|---|---|
| address | String | The controller hostname or IP address. Use "dragonfly" for the default device name, or its IP address (e.g. "192.168.1.100"). |
| command | String | The relay action to execute. See command list below. |
| relay | Integer | Relay index to act on, 0–7. |
| timing | Integer | Timing parameter in milliseconds. Used by rlpulse. Pass 0 for commands that don't use it. |
Commands
| Command | Description |
|---|---|
| rlchg | Toggle—flip the relay to the opposite state. |
| rlpulse | Pulse—close the relay for the number of milliseconds given in the timing parameter, then open it. |
| rlopen | Open the relay (de-energise). |
| rlclose | Close the relay (energise). |
Examples
Toggle relay 0
dflyDo( "dragonfly", "rlchg", 0, 0 );
Pulse relay 3 for 2 seconds
dflyDo( "dragonfly", "rlpulse", 3, 2000 );
Read sensor 2 and display it
var val = sn[2]; document.getElementById("sensor-display").textContent = val;
Show relay state as on/off text
var state = rl[1] ? "ON" : "OFF"; document.getElementById("roof-status").textContent = state;
Auto-refresh: sn[] and rl[] are populated when code.js is loaded. To keep a dashboard current, reload the script on a timer, or use setInterval to periodically fetch fresh values via an XHR/fetch call to the DragonFly's data endpoint.