As I understand pressing a button on your phone's keypad sends an in-band DTMF tone to the other party. This is not actually sending a telephone signal of any sort, just sends the respective DTMF sound over the voice path.
When an IVR prompts me for entering DTMF tones - instead of pressing a button on the phone, what if I played pre-recorded .WAV files containing the DTMF sounds real loud at my end? Assume these files have excellent quality audio in them.
Is that technically the same thing? Can it be expected to work?
Yes, that will work fine. If you could hum accurately enough, that would work too, but I wouldn't recommend it!
Related
I am using a BBC Micro:bit version 2 and have a program set up on an editor called Micro:blocks. The code is supposed to take input from the first micro:bit's microphone and play it out of the other one's speaker. But when I try it, all I get is an annoying buzzing noise coming out the other end.
I can play it correctly out of the first micro:bit only (not using radio) and it sounds fine. I can't figure out why the second micro:bit makes a buzzing noise.
With the program without radio, I messed around with how long before it played the noise, and none of the tests resulted in a buzzing noise, so I know it's probably not a timing or delay issue.
Anyways, here is my code.
Transmitting code:
when [button a] pressed
set radio group to (7)
set radio channel to (7)
set radio transmit power to (7)
digital pin write (on) to (28)
forever
analog pin write (microphone + 500) to (0)
radio transmit number (microphone + 500)
when [button b] pressed
stop other processes
radio transmit number (0)
analog pin write (0) to (0)
receiving code:
when program started
forever
if (new radio message)
analog pin write (0) to (radio last received number)
This is an interesting project!
Your program looks correct but the radio system may not be fast enough to send each sound sample as a separate message. As a result, you are just hearing a series of clicks, resulting in the buzzing noise.
You could check that the sound data is being sent and received by sending a second or two of sound and graphing the incoming samples on the receiving side. It will be slow, but you should see something that looks like a smooth audio waveform.
Assuming speed is the issue, you could try sending several samples in each packet by encoding them into a string. But even that may not be fast enough to create a smooth audio stream, especially since the encode/decode process will take time.
A different approach would be for the receiver to collect a second or two of sound samples in a list, then play them back in a burst. That would not provide continuous audio but might allow transmitting a sentence at a time.
Here is a record/playback project you might use as a starting point for experimentation.
Note that you can download this image and drop the .png file into the MicroBlocks IDE. MicroBlocks will read the project back from the image itself :)
WASAPI is documented as not sending audio data if nothing is playing any sound, e.g. this note about WASAPI in NAudio:
Now there is one gotcha with WasapiLoopbackCapture. If no audio is playing whatsoever, then the DataAvailable event won't fire. So if you want to record "silence", one simple trick is to simply use an NAudio playback device to play silence through that device for the duration of time you're recording. Alternatively, you could insert silence yourself when you detect gaps in the incoming audio.
I have written a WASAPI listener, but on my machine, it always fires even when nothing is making any sound. Other users indeed report that when nothing is playing, the signal stops.
So I think some process must be making Windows think that something is playing on my machine, but I can't figure out what it is.
How can I find the source of this phantom audio?
This isn't much of an answer, but when I rebooted, the issue went away. I am assuming that some application like Spotify was playing something, even though it wasn't audible.
This is my first time posting here. I hope you can help me with this guys.
I am trying to use a Generic RFID USB hardware (R10D-USB)in my VB .Net project.
Problem:
It seems that this RFID-USB hardware looks like it is being read by my computer as a Keyboard device. It is producing Keystrokes.
In Device Manager, it is being known as
Keyboards
----- HID Keyboard Device
also as
Universal Serial Bus Controllers
----- USB Composite Device
Now, whenever I tap an RFID in the RFID Reader. It produces Keystrokes like Keyboard.
It is typing literally as if your typing on your keyboard. So Whenever I tap an RFID to the RFID reader it would write something even in Notepad.
Concern:
What I am looking for is, is there a way I can sort of like assign it to a Port and only works unless it is being read by my VB form.
in other words, it would stop acting like a keyboard and be disabled to all other programs and activities except the program that I will make to catch all of its Keystrokes (can work on background).
Is it possible to 'hack' or develop an app that lets you launch an app by pressing an iPhones power button or volume buttons or possibly from the passcode screen?
As an example: pressing the power button 5 times launches the app or sends an emergency SMS. Or entering a certain code into the passcode / lock screen sends an SMS
No. All these features are managed by a different process than your application, and you cannot directly influence that process. You can develop a JailBreak tweak that will allow you to do so, but obviously this is not for Apple AppStore.
What you are asking about is against the Apple Developer TOS. If you do it, you will not pass the App Store Review process and hence will not be able to distribute vie the iTunes App Store. If you don't care about that, then there may be jail break hacks that can help you with that.
I have a question about detect and change input from bluetooth numeric keyboard and sending text to another applications.
My customer asked me, if it's possible this:
my customer has bluetooth numeric keyboard and he wants to use it like phone keyboard (that means one press of number 1 it's letter A, double press it's letter B etc.)
he wants this behavior of keyboard in general for all of applications in iPhone (in email app, SMS app etc.)
I'm not sure, but i think that it's not possible, because i think the application on background cant't modify key input for another apps. Or is here any way how to do that?
Something like this may be possible via a jailbreak app but definitely wouldn't be possible using the regular SDK.
If this isn't meant as a mass market tool, perhaps jail breaking is an option? I would check this out and see if it's any help http://iphonedevwiki.net/index.php/MobileSubstrate