ThreadScan_Discover — blocking Thread discovery (Native API)

Part of the Thread Network Discovery demo. This sketch:

• starts OpenThread with begin(false) (no NVS auto-load),
• brings up the IPv6 interface with networkInterfaceUp() (Thread start not required),
• calls OThreadScan.discoverNetworks() in blocking mode every 10 seconds,
• prints each OThreadNetworkInfo (network name, Extended PAN ID, PAN ID, extended address, channel, RSSI, LQI, joinable flag),
• frees results with scanDelete() after each scan.

It demonstrates the WiFiScan-style blocking pattern on Thread MLE discover (otThreadDiscover() / CLI discover).

Supported Targets

Required IDF features (sdkconfig)

Prerequisites

LeaderNode (network former) must be running as Leader within RF range.

Flash the Leader first and wait for Role: Leader, then flash this sketch on a second board.

What the sketch does

// 1) Stack + IPv6 interface only (no Thread start).
OThread.begin(false);
OThread.networkInterfaceUp();

// 2) Blocking discover every 10 s in loop().
int n = OThreadScan.discoverNetworks();
for (int i = 0; i < n; ++i) {
  const OThreadNetworkInfo &net = OThreadScan.getResult(i);
  // print net.networkName, net.extendedPanIdStr(), net.panId, ...
}
OThreadScan.scanDelete();

Expected serial output

Setup done — IPv6 interface up, Thread start not required
Thread discovery start
Thread discovery done
1 network(s) found
Nr | J | Network Name     | Extended PAN     | PAN  | MAC Address      | CH | dBm | LQI
 1 | 1 | ESP_OpenThread   | dead00beef00cafe | 1234 | aabbccddeeff0011 | 15 | -45 | 255
-------------------------------------

When no Leader is nearby:

Thread discovery start
Thread discovery done
no Thread networks found
-------------------------------------

On failure:

Thread discovery start
Thread discovery done
discovery failed (interface down, lock failure, or timeout)
-------------------------------------

If a previous scan is still running:

Thread discovery start
Thread discovery done
discovery already in progress (OT_DISCOVER_RUNNING)
-------------------------------------

Customization

Stored result capacity

The library keeps at most OT_DISCOVER_MAX_RESULTS unique networks per scan (default 16). This sketch raises the limit to 32 for denser RF environments:

#define OT_DISCOVER_MAX_RESULTS 32
#include "OThreadScan.h"

The #define must appear before #include "OThreadScan.h" (in your .ino or in a header included before it). You can also pass it from the build system, e.g. -DOT_DISCOVER_MAX_RESULTS=32. Higher values use more RAM because result vectors are pre-reserved to that size before each scan.

Discovery timeout defaults to 30 seconds in the library. Adjust before calling discoverNetworks():

OThreadScan.setScanTimeout(60000);  // ms

Limit to one channel (11..26) with OThreadScan.setChannel(15); 0 scans all supported channels.

Troubleshooting

Startup order: Start LeaderNode (network former) first and wait for Role: Leader. Then flash this sketch.

See also

• Thread Network Discovery — group overview — all three discovery patterns.
• ThreadScan_Async — non-blocking scanComplete() polling.
• ThreadScan_Callback — per-network streaming callbacks.
• CLI ThreadScan — CLI equivalent (discover command).

License

Apache License 2.0.