Hi Everyone,
I need a little bit of help with my current project. It's probably a very easy question but not having done something like this before I am really not sure of the answer.
I have created circuit for my aircraft. It's just a circuit that reminds me when certain conditions exist by inserting a bleep every few minutes in to my intercom system. My intercom system has an external audio input which allows you to connect an audio device in to the system which routes through to the aircraft headsets.
From the manual of the intercom, it says the audio input impedance is 1V/600 ohms.
My circuit simply outputs the bleep when certain conditions are met using the SOUND command. Everything in the circuit works on my project board but I have not tried it in the aircraft yet and simply just used 64ohm speaker to test. At the moment the wire comes out the PICAXE pin with a capacitor in series with the wire (as per the PICAXE manual).
Then I found this thread:
http://www.picaxeforum.co.uk/showthread.php?16776-Speakers-connected-to-a-Picaxe
It suggests a different arrangement for connection to an amplifier by using 2 x 1K resistors and 2 x capacitors. I have 2 questions, would this be the correct arrangement to connect to my intercom given the '1V/600ohm' specification. Also, on the diagram from that thread, it shows the diagram twice for the audio amplifier connection but the capacitor values are different (it looks like an error but I don't know which capacitor values are correct).
Lastly, the audio input on the intercom does not have an independent volume control. I can only change the volume of everything connected to it so I wanted to add a volume control for my PICAXE circuit. At the moment, I have just used a 500ohm trimmer on the wire. Would this be the correct thing to do and would that still work with the resistor/capacitor arrangement shown in the thread pointed to above.
Many thanks in advance.
Steve
I need a little bit of help with my current project. It's probably a very easy question but not having done something like this before I am really not sure of the answer.
I have created circuit for my aircraft. It's just a circuit that reminds me when certain conditions exist by inserting a bleep every few minutes in to my intercom system. My intercom system has an external audio input which allows you to connect an audio device in to the system which routes through to the aircraft headsets.
From the manual of the intercom, it says the audio input impedance is 1V/600 ohms.
My circuit simply outputs the bleep when certain conditions are met using the SOUND command. Everything in the circuit works on my project board but I have not tried it in the aircraft yet and simply just used 64ohm speaker to test. At the moment the wire comes out the PICAXE pin with a capacitor in series with the wire (as per the PICAXE manual).
Then I found this thread:
http://www.picaxeforum.co.uk/showthread.php?16776-Speakers-connected-to-a-Picaxe
It suggests a different arrangement for connection to an amplifier by using 2 x 1K resistors and 2 x capacitors. I have 2 questions, would this be the correct arrangement to connect to my intercom given the '1V/600ohm' specification. Also, on the diagram from that thread, it shows the diagram twice for the audio amplifier connection but the capacitor values are different (it looks like an error but I don't know which capacitor values are correct).
Lastly, the audio input on the intercom does not have an independent volume control. I can only change the volume of everything connected to it so I wanted to add a volume control for my PICAXE circuit. At the moment, I have just used a 500ohm trimmer on the wire. Would this be the correct thing to do and would that still work with the resistor/capacitor arrangement shown in the thread pointed to above.
Many thanks in advance.
Steve