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Showing posts from September, 2007

GSM-Remote (Test phase 1)

Today i completed the DTMF decoding circuit and interface it to the micro controller and DTMF tone was generated by the PC and fed to the decoder. After all the connections i wrote a test code for micro controller to get the decoded signal. With an interrupt i manage to get the decoded values from the tone generated.
To view what i am getting i connected the LCD and found some problems and after a while i menage to fix it. from the flow you can see how it works. Then i have to test this from a mobile phone and for that i need to make a small preamplifier to control the volume.

GSM Remote - Design Stage started

After few days of busy office works i menage to start the designing of DTMF decoding part. This part will be interface to an micro controller to identify which key the user has pressed when he or she was on the call and trigger the given functions.. so hope there is muh to think so untill then please hold on..

GSM Remote on progress

Finally i got an Siemens C45 mobile phone. when i got it , it was also kind of dead (not functioning well) so i took the PCB and after some cleaning and heat up the fella works fine. I did some changers to the SIM socket location and wired the battery points. Today i tested the battery charging part and it also works fine.
Have to make a small circuit for charging part and DTMF decoding part. The interesting part will be the serial connection between micro controller and the phone by which it can be controlled.

Delays

I am sorry say there is a huge delay to start the mobile remote project. Problem is the phone i got have a network issues so it will take some days to fix or i will find another one..until then it will be on hold..

GSM Remote

Its been few days that i was trying to get a damage mobile phone, any model is fine for the purpose that i need. Luckily i got a NOKIA 1100, which is an old series of nokia. The phone was in a terrible condition. I mean it was taken from water and some parts of the PCB was getting corroded.

I did some clean up work and wala.. it was well cleaned enough. So i did some research on the nokia 1100 PCB and connected the voltage links and gave 4V and it was on but nothing on the screen. screen is damage, which i don't need later but at start i need it so i fixed and put my SIM and it appears NO SIM INSERTED.. so i did fix that problem and wala.. the phone works fine.

Tonight i will take some pictures of it and post it here.. next step is little hard but will try it. Tonight nokia MBUS/FBUS will be wired and interface to my Laptop for further investigations..keke so keep on peeping.