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Bing Speech Recognition

How to add the Bing Speech Recognition robot skill

  1. Load the most recent release of ARC (Get ARC).
  2. Press the Project tab from the top menu bar in ARC.
  3. Press Add Robot Skill from the button ribbon bar in ARC.
  4. Choose the Audio category tab.
  5. Press the Bing Speech Recognition icon to add the robot skill to your project.

Don't have a robot yet?

Follow the Getting Started Guide to build a robot and use the Bing Speech Recognition robot skill.

How to use the Bing Speech Recognition robot skill

This is a speech recognition skill for ARC that uses the Bing Speech Recognition cloud service. It is one of the most accurate speech recognition services available.

Two Version Of This Skill

There are two version of this robot skill, this one and the Advanced Speech Recognition. This version of the robot skill uses a shared license key with Microsoft that enables ARC users to experiment and demo this robot skill. Because this version of the skill shares a license key, users may encounter errors if more than one ARC instance is using this skill. For serious testing and development, we recommend setting up your key with Microsoft by using the Advanced Speech Recognition instead.

Microphone Recommendation

Most robots make a lot of noise, so locating the audio input device on a robot is not a practical solution. It is best to find the microphone on the controlling PC/Laptop, on yourself, or somewhere in the room (away from the robot). Turning the gain higher on the input device will allow voices to be recognized from across large rooms and increase false positives. Test with different gains for the best resolution. Experiment with varying locations of microphone and volumes for the best setup for your environment. Ideally, use a headset or Bluetooth mic rather than your laptop microphone.

Main Window

1. Start Recording Button
This button starts the Bing Speech Recognition; it will detect silence until you speak, then it will detect the words you are saying and display them in the Response Display.

2. Audio Waveform
This gives visual feedback that your audio input device (microphone) is configured correctly and is picking up voice/sounds.

3. Response Display
Here you will get speech recognition feedback. It will show the text version of your detected words or silence.


1. Phrase List
 This is a list of default phrases with the ability to customize and add more phrases.

2. Command List
 This is a list of default commands corresponding to the phrases in the same row, with the ability to customize and add more commands.

3. All Recognized Script
 This script will execute for every detected phrase. If there is no match for recognition, this script will still be executed, but the variable will be empty. You can tell if there was no speech spoken because the variable will be empty, and this script will be executed.

4. Variable Field
 This variable holds the text from the speech recognizer. This may be used in your script for determining what was spoken. If the variable is empty, no speech was recognized (i.e., silence).

5. Auto Record Checkbox
 If this checkbox is enabled, the skill will begin recording audio when it has been detected. The threshold is adjusted in the Level Threshold setting.

6. Level Threshold Field
 This adjustable threshold level is used for both Auto Recording (if enabled) and stopping recording. If you find that even in manual mode, the recording manually stops too quickly before your sentence is complete, lower this value.

7. Silence Count Field
 This count sets how many times the energy volume is below the level threshold before recording is stopped.

8. Max Recording Field
 This represents the maximum duration of the recording. *Note: Currently locked to 10 seconds.

9. Strip Punctuation Checkbox
 If this checkbox is enabled, punctuation will be stripped from the detected recording when displaying it on the Response Display. This is helpful when you're looking to detect certain words or phrases.

10. Setup Microphone Button
 This button is a shortcut to the properties of your installed audio input devices. Verify that your device is working by watching the soundbar for movement when you speak into that device.

11. List Management Buttons
 These buttons manage the rows of phrases. They move the rows up and down, insert them, add more to the bottom, and delete them.

12. Language Drop-down
 ARC uses the Microsoft Speech Recognition included with Windows. All languages supported by Windows Speech Recognition are also supported in ARC. You can configure Windows to listen to any language. ARC will default to EN-US (English) language if installed. Otherwise, ARC will default to the first installed language. If more than one language is installed, a language may be selected with this drop-down.

*Note 2: Languages support by speech recognition depend on the Microsoft Windows operating system configuration. View the Microsoft speech recognition guide here to view supported languages.

13. Not Handled Script
 This script will execute for every detected phrase not in the phrase list. If there is a match from the phrase list, this script will not be called.

How to Use Bing Speech Recongition

A detailed tutorial provides an example of using this robot skill in conjunction with PandoraBot AI to have a conversation with your robot. You can find the tutorial by clicking here.

Control Commands

Control commands will send instructions from one robot skill to another. Read more about the ARC control command feature by clicking here.

ControlCommand("PandoraBot", SetPhrase, $BingSpeech)

When this skill detects a phrase, it will be assigned to the variable, and the specified script will execute. With this model, you can have this skill send the detected speech to a PandoraBot skill using ControlCommand().

ControlCommand("PandoraBot", PauseListening)
ControlCommand("PandoraBot", UnpauseListening)

Controls the state of the PAUSE checkbox, which pauses the listening for VAD auto recording. If VAD is disabled, the PAUSE checkbox does not exist. The pause checkbox prevents the VAD from automatically starting recording.

ControlCommand("PandoraBot", StartListening)

Presses the Start button, which begins listening to audio through the microphone to convert from speech to text. Sending this control command is the same behavior as pressing the Start button.

ControlCommand("PandoraBot", StopListening)

Presses the Stop button, which stops the recording of audio that will be converted from speech to text. The Stop button is only visible when the recording is active. Recording can be activated by either pressing the Start button or auto-recording when VAD is enabled.


Here's an example of the skill in action combined with the Cognitive Vision and Cognitive Emotion services.


This service requires an internet connection which means that a second USB WiFi adapter or an ethernet connection may be needed. Read about having 2 network connections here.

Headset or External Mic

Using a headset or external mic will produce dramatically better results compared to the internal PC/Laptop mic. Using a headset or mic will enable the recognition engine to "hear" your voice much clearer with less background noise. The background noise of the laptop, motors, radio, and room echo will cause the recognition software to return False Positives. This means the software recognizes an incorrect phrase. An external mic will also prevent the recognition software from hearing the robot speak. In short, it is important to use a Mic Headset or external Mic for a positive Speech Recognition experience.


Configure Audio Input Device

You might have to adjust the microphone input volume/gain. To change the mic volume, use the Microsoft Windows volume mixer, and first, make sure you have selected the correct input device. Your laptop or computer may have a few different mic devices. Maybe one is on a remote camera. Find the mic you'd like to use and adjust the volume. To find the volume settings that are ideal on your computer, follow these steps:

1) Right-click on the little speaker on your system tray

2) Select "Open Sound Settings."

3) In the "Input" section of the Sound Settings, you'll notice a little VU meter beside the active device. Make sure your active device is indeed the microphone you want to use. By making sounds, the VU meter should move.

4) Click on the "Device Properties" and locate the volume slider for the microphone. We usually have our volume set for 78. Play around with different volumes until you see your voice being picked up by the VU meter. Adjust the volume input level/gain to display your voice's regular volume near the middle of the VU Display graph. If the level/gain is too high, the recognition software will not work because the input audio will be distorted.

Voice Training
You may train your computer for speech recognition by using the training wizard. Find the training wizard under Speech Recognition within the Windows Control Panel.

Related Tutorials

Related Hack Events

Related Questions


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Edit 2: Now its not again....I'm getting:

Server was unable to process request. ---> A task may only be disposed if it is in a completion state (RanToCompletion, Faulted or Canceled).
Maybe their server is having issues. Works fine now.

User-inserted image
Ok DJ thanks for checking. I’ll try again in the AM.

Is there any way to directly set up Bing Speech Recognition to use a wake word?

#13   — Edited
In the Speech Recognition robot skill, add a phrase with a ControlCommand() that unpauses the bing speech recognition?

And then have the bing speech recognition re-pause itself after it detects a phrase?

Use the Control Command, here's a manual on how to use the ControlCommand and access available commands for each robot skill:

Essentially, you can right-click in the editor or press the Cheat Sheet tab

PS, the question had been moved from Will's unrelated thread about his youtube channel to here.
@TMesserschmidt, DJ's suggestion is exactly how I set up my robot with a wake word. I used the name "Robot". Not real creative bit it works. LOL. 

I also set a set of lights to flash for the amount of time Bing was listening. That way I know that Bing is actively listening and for how long. That really helped.
#15   — Edited
Here's the process of how I added a wake word. 

Bing is normally paused and wont listen till the script in the Speech Recognition robot skill starts it or you push it's Start Recording button.. 

Simply add the Speech Recognition robot skill to your project. Make sure it's working and listening. 

Add this Ez  code and modify it to work with your project. 


Set(D12, on)   #D12, on turns on the scanner lights to let me know Bing has been called to listen,
ControlCommand("Bing Speech Recognition", StartListening) #Starts Bing listening
ControlCommand("Speech Recognition", PauseMS, 2000) #Paused this Speech Recognition control so it wout listen for a while
Sleep(1500)  #Keeps script alive so the scanner lights will let me know how long Bing is listening.
Set(D12, off)  #D12 turns off the scanner lights
TIP: If you get false startups of this control just increase the Continence level until it hears the wake word and nothing else. Use a wake word that is not common or is not used too much around the robot. 

Nothing else should be in the Speech Recognition robot skill except this wake word. 

Works just like Alexa! 

Have fun!!
I'm having an issue with VAD. When its on I get errors, mostly it hangs sending for a long time then returns an error: a task may only be disposed if it is in a completion state: ran to completion, fault or canceled.

If i turn off VAD i do not get the issue. But then have to press stop recording button which defeats the purpose.

Can anyone repeat this issue? Just about to give up on this and move on to another skill.
No problems here. Just used the skill with "Auto Record Checkbox".
Will, are you using this robot skill on 2 or more ARC instances at the same time? That might cause the issue. This free version of the recognition uses a shared key and has a limit to how many users can use it at once. There's also a limit that each user can only be used once at a time. If you're using a production or dev environment, I'd recommend using the advanced speech recognition here:

That way, you're in charge of the key do not need to depend on sharing keys with other users.

When trying to add Bing Speech Recognition I'm getting this error message.  Please help, thanks in advance.

Version: 2021.11.28.00

NAudio.MmException: InvalidHandle calling waveInStop
at NAudio.Wave.WaveInEvent.StopRecording()
at ARC.UCForms.FormBingSpeechRecognition.ConfigPressed()
at ARC.UCForms.FormMasterBase.O5M2kVWMr4Pp0G1QpBRH(Object )
at ARC.UCForms.FormMasterBase.xQYxVChkhQn(Object , EventArgs )
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.Label.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
#21   — Edited
Doesn't look like you have a sound card with an input device on that computer. This robot skill can only work if there is a working soundcard with a mic or line in.
Thanks DJ, I’ll get that fixed and try tomorrow.:)
Hey All, I'm pretty sure that anyone with experience with this skill should be able to answer this. Can you tell me how to activate the phrases within the Bing Speech Recognition skill? I must be missing something easy.

I have no trouble having the phrase recognized by Bing. Example: "Look up"

User-inserted image

But the action associated with the phrase "Look up" (in the configuration) isn't executed. The characters exactly match but it seems like the phrase isn't detected.

User-inserted image

I've even tried removing my "All recognized script" and "Script for not handled" but that didn't help.
#24   — Edited
Maybe you have a blank space at the end of "Look Up"? And it's written as "Look Up " Edit the phrase and remove the space if there is one.

User-inserted image
#25   — Edited
One trick I learned was to speak the phrase I wanted into Bing. Then I would copy and paste exactly what Bing returned into the command box. I would get 100% recognition that way. A lot of times what Bing returned and what I thought was the correct way to write the phrases were completely different.  Bing would return words starting with capital letters, weird punctuation and such. I would copy what bing thought was correct regardless of proper sentence and word structure. And DJ is correct. Make sure there are no spaces at the beginning or end.
Have you tried to execute your code within the editor? Does that work?
Thanks @DJ, that was the issue, I knew it had to be something simple!

I had cut and pasted everything into the phrase list, line by line. I just figured out how it happened. I was cutting and pasting text that was at the beginning of a line of text. When you use cut & paste like that you can inadvertently grab the spaces between words because you are removing all the text.

That's my bad, something to keep in mind for the future.
I updated ARC for the next release to strip whitespaces from the phrases so it won't happen again