Remote by Mobile Phone

[e_aph]

Hi

I purchased the components to assemble this project (040415) including the programmed PIC, unfortunately I still can't get it to work.

1/ I have adjusted the P1 for DTMF sensitivity but it doesn't seem to make any difference.
2/ When the phone answers there is a loud 'hum' and no message but if I press S1 my pre-recorded message is heard.
3/ The instructions say there is only one adjustment but there are 2 preset pots! what is P2 for?

I have limited knowledge of electronics and no oscilloscope only a digital multi meter so any help you could offer will be most useful.

Thanks in advance.

[Elektor Editor]

1. there is a problem with the audio from your phone not being applied to the DTMF decoder and the PIC. (line E)

2. PIC contains wrong firmware or it is not executing firmware. Did you purchase the PIC from us or program it yourself.

3. P2 has the obvious function of setting the volume of the prerecorded message played back into the phone.

You should have access to an oscilloscope to be able to solve this problem.
Hope this helps.

Jan Buiting

[e_aph]

Jan

Thanks for reply and suggestions.

1/ I will see if I can check audio output from mobile.
2/ I purchased the pre-programmed PIC from you.
3/ Ok
4/ I don't know anybody with an oscilloscope so this could be a problem.

Andrew

[e_aph]

Hi

Just found out that the circuit part for IC1 is - MT8870BE but I could only buy a MT8870DE. I have tried comparing them without finding if the DE version can be used as a substitute. Can anyone advise please?