25 February 2011

Cellphone remote control, step 1

Following the request described a couple of months ago, I haven't stopped thinking of the cellphone remote control. So, an ATtiny2313 will be the processing unit and to ADC the incoming sound command I will use a tone decoder.

Why not build a software frequency counter? Because it would keep the 2313 running all the time (that's about 99,999% of the time needed) and it would use internal timers that I need to validate the incoming command sequence.

A simple tone decoder is the good old NE567 that I located inside a PSTN answering machine from 90's. The local shop doesn't sell them anymore.

Some more details. The ring tone will be bitonal, so that any ambient noise gets cancelled when the remote cellphone rings. High tone will be used as a carrier, low tone as a signal to the microcontroller. Low tone will be chosen away from flies and mosquitoes sound :-) The ON 001000100010 decoded sequence will have a lower frequency than the OFF command.

Let's warm up the iron!

22 February 2011

FT-817 Interactive Frequency Reader - fast dial

One request I got while designing the I.F.R. was to allow a default value for 100/10/1 GHz and 100/10 MHz. This way a frequency can be entered with fewer keypresses.
Like a QSY to 10'368'367'0oo Hz would require to dial in only 8-3-6-7-0-# instead of 1-0-3-6-8-3-6-7-0-#.

This feature can now be (de)activated from the configuration mode, key C. It applies also to normal operations, when the transverter math is not used.

18 February 2011

FT-817 Interactive Frequency Reader - PREVIEW video

Here is a 3'33" youtube video showing how the Interactive Frequency Reader works right now.

The firmware shown is taylored for users that use FT-817 in conjunction with a microwave transverter. Please note that not all implemented functions have been shown, the firmware can be extended and it is still subject to changes.

Please leave feedback and, most important, ideas.

17 February 2011

Statistiche IAC di gennaio 2011

Guardando il mio log e la classifica mensile inviata da BPU, mi sono chiesto se non possa essere interessante vedere la distribuzione per quadratoni dei partecipanti allo IAC.

Con un paio di operazioni in OpenOffice Calc, ecco un risultato tabellare:

Count - LOC Banda

LOC 50 144 432 SHF UHF Total Result

JN44 4 4 3
1 12
JN45 5 15 7 3 10 40


JN53 1 7

1 1 1 2 5
JN55 3 2 2




JN65 1 1

Total Result 14 33 15 4 13 79

E la rappresentazione grafica:

Traete voi le conclusioni sulla base della vostra banda preferita >30 MHz, ricordando che questi numeri rispecchiano la distribuzione geografica di chi ha inviato i log, non necessariamente dell'effettiva presenza "in aria".

14 February 2011

FT-817 Interactive Frequency Reader

... or "detachable display". A first version is currently working on my bench. It is taylored for microwave transverter users, so the current features are:
  • configuration mode accessed at frequency reader start-up with parameters in EEPROM
  • holds baud rate setting
  • holds transverter mode on/off
  • holds LO+IF and LO-IF math mode
  • holds frequency update delay in 15 x 100 ms steps
  • holds two L.O. values down to 100 Hz resolution
  • direct microwave frequency dial, with invalid FT-817 frequency control
  • mode change
  • VFO A/B toggle
  • VFO A=B
  • RIT on/off
  • LO value selection (#1 or #2)
  • 15 onboard frequency/mode memories
Since many frequency values can now be entered, keypad digits can no longer work as jolly buttons for other advanced features (a further study on HAM microwave bands is needed, though!). If the transverter mode is OFF, then the frequency reader takes direct VFO value (with valid frequency check; i.e. 156'000'000 Hz will not be sent to the radio because it is out of FT-817 range).

I plan to record a demo video in the next days, so that I can gather readers' feedback before a final public firmware version is packed up and documented.

01 February 2011

FT-817 Frequency Reader, present and future

Firmware development has not stopped, and now the frequency reader has a bigger brother: the Interactive Frequency Reader.

Based on the same circuit core (ATmega88/168), it adds the matrix keypad to the external display readout.

Most of the recent work has been towards enabling the I.F.R. to accept direct microwave frequency dial and QSY the FT-817 to the proper frequency, according to the selected L.O. value.

Meanwhile I am completing the Frequency Reader documentation, so that it will be up on the website soon. The stand-alone display firmware is now stable and ready for the general public.

Heat up your soldering irons!