Add Synchro Record to Your DVD Recorder (without Opening the Case!)


Introduction: Add Synchro Record to Your DVD Recorder (without Opening the Case!)

About: I am Married to Beth, I am an Architect and have four wonderful children

Allows Synchro record from a set-top box (mine is the Sony terrestrial digital reciever) to a DVD player which dosn't have syncro record.
You can then record programmes automatically by selecting them for record on the set top box with no need to programme the DVD recorder.
You will not need to open either your set-top box or DVD recorder so no warantees or contracts are affected.

Step 1: The Black Box

The system comprises of a black box which connects between the Set-top box and DVD recorder using a piggy back SCART connector, an off the shelf plug-top power adaptor (from an old Black and Decker cordless drill charger) and a IR LED on a length of cable

Step 2: Inside the Box

The box uses a motorolla MC68HC11E9 processor which I have salvaged from the bin (it has already had it's EPROM programmed) running in bootstrap mode which allows code to run in the EEPROM. all it has then is an input from pin 8 of the set-top box SCART (12V indicated synchro recording in progress) and an input from pin8 of the DVD SCART (12V = dvd ON, 0v = dvd IN STANDBY).
There are two outputs, one drives the IR LED (scrounged from an old IR handset) via a suitable resistor (about 470ohm giving about 7.5mA trhough the LED) and annother output to flash a status LED on the front panel (just so you can see the thing is still working)

Step 3: Programming the Code

Programming is done through the five pin connector on the PCB (the jumper between 2 pins indicates the code in the EPROM should be run, no jumper starts up in bootloader mode ready to be programmed)
To program the code in you will need a 5V supply to power the board during programming (the PSU used in normal operation is fine for this) a 12V supply for programming the EPROM and a serial connection to a PC, the RS232 levels on the programming interface are 5V so you will need a convertor with a LT1181 or similar to give true RS232 levels)

Step 4: Making the PCB

The PCB can be made from the images below, you will need to scale and print them onto acetate then expose them onto sensitised board.
Make sure that the artwork when printed is scaled correctly in BOTH directions.
Attach the components as shown in the image.
The DWF file has scaled printable versions of the PCB, schematic and layout. For a wiewer go to

Step 5: That's It!

Here is an image of the box working



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    8 Discussions

    Yeah, mini discs didn't quite catch on here in the US. Now I'm finding it extremely difficult to find the discs now a days. =(

    This needs an Event sequence One wants a Recording to Take Place What do You do to Initiate this What Events does the hardware do to accomplish this ? I could figure this out from the provided files -- maybe eventually ;) could you DOCUMENT what it does ?

    1 reply

    Hi, I am afraid I don't have time to fully document how it works, however I can give you some hints which will perhaps help you make sense of the code. The source code for the device is in two files slprom and smartlin (afraid all file names are messed up since this was written on my Archimedes) in SMARTLIN/S (Equates are in SMARTLIN/EQUATES) Because the processor is not fast enough to generate a 38kHz modulated output using the output compares and interrupts alone the foreground process (mainloop in slprom) does nothing other than modulate the output to the IR transmitter when it is turned on. The transmission of an IR command is done by StartIRCommand in slprom, this sets up a timer to generate an interrupt after 1ms, each successive timer event (processed by OC1Handler) in main then generates a series of further timer inturrupts at all of the points in the IR command where the output needs to change state. To recap and IRcommand is initiated by StartIRCommand, output by OC1Handler and modulated by MainLoop. (ignore all other routines in slprom - they are just utilities) Startup just resets variables and sets all the hardware as required. CopyVecs is only needed because I am reusing scrap (already programmed chips) by running them in boot loader mode (see Motorola's application note on boot loader if you are interested. This is also why I have part of the code running in EEPROM and part in EPROM with funny vectored calls. If you have a virgin processor you can simplify things considerably. The routine which does all of the sequencing of events is RTIHandler (This is called every 50ms or so by the RTI interrupt) The start of RTIHandler maintains the output states and debounces the two inputs (one input senses if the recorder is in standby and the other detects the signal from the DTV box which indicates programme needs recording) The signal from the DTV box is the one that initiates sequences of commands to start and stop the recording process (when signal goes high a start sequence is sent, when it goes low a stop sequence is sent) The sending of the commands is controlled by flags and a holdoff delay (this is to allow the recorder to process the commands, my recorder is VERY slow!) Hope this helps Pete

    I'm listening to my minidisc right now, and I feel the same way! =)

    Thats more or less why I did it. If your reciever has the option of selecting the programmes to record from an on-screen programme chart then you won't need to enter any times into timers - just one press and you are done


    12 years ago

    This in an interesting idea.. I could try it to get rid of making the same timer settings twice when using my DVB-T receiver and DVD burner. Although I usually have just left the receiver switched on and only timed the DVD player to start recording when the desired program begins...

    Good point Dan I knew I had forgotten something! I have no parts list at the moment - I may add one later. The code is all as it came off my Acorn so it will need some work if you want to use a PC Pete


    12 years ago

    it seems like we also need your firmware code and parts list to build this? can you upload?