Hobbies: Mobile Phones
Mobile phones (especially those ones manufactured by Nokia) are one of my favorite hobbies. Personally I think Nokia has the best-designed phones at the moment (regarding hardware, not "featuritis"). If you ever disassembled a phone and had a look at it you know what I'm talking of. And when it comes to usability Nokia is the market leader - handling a Nokia phone is (as it always has been) "plug and play".
But there are also some dark clouds coming up the blue Nokia sky ... I had some VERY disappointing experiences when my Communicator had to be serviced. This is not how the market leader should behave, and it's the reason I'll NEVER MORE buy any new Nokia phone, I'll just keep collecting (mainly older) phones from second hand sources (like flea markets etc.).
I have designed a non-standard MBus interface. The common solutions use one gate of a 74HC14 for signal level adaptions (+5V / 0V at mobile side, +12V/-12V at the serial port). Since using one gate out of six is not very economic :-) and you don't always have TTL ICs on stock at home, I just used 2 transistors.
Here's the schematic:
WARNING: If you are using this design you do this completely at your OWN RISK !!! If you roast your mobile or damage it somehow else using this design I can't be held responsible. Thank you.
And this is my home-brewed mbus-interface using the common solution with a 74HC14 in SMD technology:
I'm also collecting all kind of Nokia phones. Currently I own at least one peace of each of the following models which are all still working or brought back to life:
More to come soon ... :-)
If you are interested in swapping phones to complete both your and my collection, drop me a note. I can offer the following phones for exchange:
Working: 3210, 5110, 6110, 7110, 7650
Not working: 5210, 6210, 9210, (maybe parts missing, displays damaged, flash corrupt, covers damaged or missing, etc.)
Internal aerial modification for Nokia 6150
A friend gave me some old mobile phones, one of them being a Nokia 6150 in good condition. As I wanted to have something unique, I thought about modifying it to work with an internal aerial.
You'll find some photos of my 6150 enclosed. They show how I did the modification. It works not *that* well as the original antenna according to "NetMonitor", the RX is about 5-10 dB weaker. But I don't mind - it looks cool and certainly is unique ...
The wave-length "lambda" is 33 cm @ 900 MHz:
lambda = c / f
( c = 300.000 km/s ; f = frequency in Hz ; lambda in meters )
The aerial needs to be lambda / 4, hence it has to be about 8,25 cm. You might optimize it using "NetMonitor" - start with a 9 cm aerial and cut mm after mm until RX-level reaches a maximum. But it is not necessary in general, using a 8,25 cm peace of wire will do the job.
Use some kind of thin insulated wire to build the aerial, solder it to the antenna connection pad (where the original antenna gets contact to the PCB) and place it inside your 6150 like shown on my photos.
Ah yes ... one thing ... I have been to lazy so far to seal the hole where I cut off the original aerial ... you might use some kind of glue or similar which is for example used when building model cars.
K.Choo reported that he has done this mod to his 7110 and it still works :-) , he used epoxy clay to seal up the hole (thanks for that information).