Could not start scanning, state is unknown (not poweredOn)

Hello, I’ve tried to scan for BLE devices:

noble = require('noble')

noble.startScanning();
console.log "Scanning"

this results in a error message (?):

noble: Could not start scanning, state is unknown (not poweredOn)
Scanning

Is the code wrong or is the message wrong? Is intended, that a message is printed on the screen? Shouldn’t an exception being thrown if a precondition is not met?

I’ve tried 1.1.0 on OS/X 10.10

Cheers, Torsten

Issue Analytics

State:
Created 8 years ago
Comments:9

Top GitHub Comments

4reactions

carlstcommented, Aug 13, 2015

@TorstenRobitzki: you might try waiting for the state to become poweredOn:

noble.on('stateChange', function(state) {
  if (state === 'poweredOn')
    noble.startScanning();
  else
    noble.stopScanning();
});

1reaction

quique123commented, Jul 29, 2018

Im trying to read a ble char from a ble relay board from my rpi3. startScanning() simply hangs or returns error that ble device isnt powered on. Why is that?

I know the ble on the rpi3 works because I use it to write to the relay board every so often and it works fine.

Top Results From Across the Web

How to power BLE back on using node-red-contrib-noble ...

Any ideas how to prevent or catch this error? Error scanning for devices: Error: Could not start scanning, state is poweredOff (not poweredOn)....

sandeepmistry/bleno - Gitter

hello im using bleno for a demo but i cannot get it start advertising , everytime it ... Could not start scanning, state...

noble.state is set to "poweredOff" immediately after running ...

When the state is set to "poweredOff" it stops scanning so I am never able to find devices. Here is my code: const...

@lemariva/noble - npm

Some BLE adapters cannot connect to a peripheral while they are scanning ... NOTE: noble.state must be poweredOn before scanning is started.

API misuse | Apple Developer Forums

unknown state, just as we implement the centralManagerDidUpdateState method. In any case, the state doesn't change until the scan is called. So, how...