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788t remote roll/ movie slate


ChrisH

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Hey guys I am building a remote roll box that will roll two 788ts and feed timecode to movie slate.

Below is a picture of the prototype circuit I built for movie slate, it's that same as Gotham sounds idea.

This circuit uses the GPIO logic out (pin 8(+) and pins 6&7(gnd)logic out set to high) from the db-15 connector to trigger a read relay which allows timecode to pass to the iPad. When timecode is received on the iPad it rolls movie slate. Timecode is padded down using a 68k resistor in line with the TC(+), and a 22nF capacitor and 1k resistor between the tc(+) and ground.

My plans are to add a button that will roll two 788ts, also I would like to use the clink out port as my interface to the 788t instead of the db-15. S here are my questions for other users and for sound devices. I have called Paul and John several times.

1. Can I get both timecode output and GPIO from the clink output?

2. How does logic make the 788t stop? Is a pulse roll and and holding the button stop?

3. Finally my first and biggest problem so far is that this system as well as another padded cable is returning timecode into the 788t! So my cable has only the ground the and the TC out pins attached yet when I plug in the device the timecode compare screen shows a receive timecode what is worse is that 6 hours after plugging in the cable I had lost sync and was off by 12 seconds! Could timecode output be feeding back up the ground even the input pin is attached to nothing?

I am hoping Jon or Paul will call me back now but if anyone else has any knowledge I'd love you to share it. Also once I get finished I will be selling these little remote roll boxes. They will have a button a red led and a plug with a set of tails to interface with whatever your recorder is( TC input, tally and GPIO, and iPad output.

post-2879-0-11003200-1362168077_thumb.jp

post-2879-0-92891400-1362168091_thumb.jp

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You should take a look at the manual in regards to pins and logic.

 

GPIO doesn't have any TC running through it. Only C.Link is capable of that.

 

The logic (high/low) for 'stop' on the output is in a menu on the 788t for the Assign: LOGIC OUT pin.

 

For TC issues, I had a similar problem on my cart linking the lemo for tc output and input. Never figured that out (nor did I try to). So I'd certainly like to see someone chime in on the proper way to wire a TC cable with in/out on the same line.

 

As for soldering, you should be putting the component and its leads from the other side of the board, and then soldering the leads to the side that you're currently using. It's cleaner and you'll get better solder joints.

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I am aware the DB-15 does not have time code. I am asking if the clink output has both time code and the logic io that I need. I would like there to be only one cable to each 788. I have read the manual thoroughly. It does not say whether the logic io is parallel on clink and DB-15, and it only says time code in on the clink.

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I am aware the DB-15 does not have time code. I am asking if the clink output has both time code and the logic io that I need. I would like there to be only one cable to each 788. I have read the manual thoroughly. It does not say whether the logic io is parallel on clink and DB-15, and it only says time code in on the clink.

 

C.Link doesn't have any GPIO, only Serial Data, Power, Word Clock and Time Code.  You need a CL-1 to get a GPIO from the C.Link.  That's why the straight GPIO pins are in the DE-15 connector.

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Copy that thanks Matt.  Thats what I have come to understand from my experiments clink did not work similarly to GPIO.  My next question is how does the GPIO work with remote roll.  I would like to make a momentary switch (big red button normally open) that can roll the machines.  Regarding the GPIO in the DE-15; to roll the 788t you need a logic high voltage?  how do you stop it? can Roll be achieved with a pulse and stop be achieved by holding the button?

Also can logic voltage be triggered by the 3v dc power out put on the clink cable or would I be better using a voltage regulator to bring 12v cart power down to logic voltage levels?  Also would I be better to rely on clink linking to roll multiple 788t's and just triggering the master through GPIO, or is it worth it to link multiple units with GPIO?  

Finally all this is to achieve digital sound reports with accurate timecode in/outs, also to enhance a mixers ability t deliver multiple recorders worth of tracks.  Files of the same size will create an easier workflow for post.  It would be great if CL-wifi app could solve all these problems by adding a sound report page with PDF export function....

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Chris,

 

There is a pretty good tutorial on 788T multi-machine linking in the Sound Devices Tech Notes section:

 

http://www.sounddevices.com/notes/recorders/788t-linking/

 

It's a little dated and not quite how I would go about it, but it is good for basic information.  I think an easier way to do wordclock and timecode would be to use C.Link cables to loop from Out to In on your machines.  If you want to do more than three machines, you will need to jump timecode and wordclock from the first machine to the fourth.  We found that the jitter on the C.Link cable after the third machine makes the 4th and higher machines unstable.

 

No need for power at all.  The GPIO is "Logic Low" so simply connecting it to ground will trigger the selected function.  You can select the function in Menu Item 92 - Keyboard/Logic In: Assign.   Select Shortcut 01 to use Logic In 1, Record Button and Toggle.

 

Now use a normally open push button switch to connect Pins 6 and 9 in the DE-15.  One push will start record and another push will stop record.  As shown in the tech note, you can tie multiple GPIOs together to roll all the machines with a single switch.

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Here is the finished product with remote roll for two 788ts and timecode driven iPad roll for movie slate.

Comes with the big juicy red button and rolling light:)

Additionally this unit gives the mixer digital inputs on channels 7/8 of their primary 788.

post-2879-0-78225700-1362953477_thumb.jp

post-2879-0-96174100-1362953557_thumb.jp

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  • 2 months later...
  • 1 year later...
  • 10 months later...

Apologies for resurrecting this thread, but I've just happened upon it whilst seeking a solution to drive Movie Slate from a Sound Devices 664.

There is no equivalent DE15 multi-function connector on the 664, of course, but Richard Paterson's post (#12) gave me hope as it seems to indicate one can use the 5-pin LEMO TC connector to gate the time code signal to the iPad for remote roll/cut functionality.

Has anyone done anything similar?

Cheers.

- Scott

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The 664 has a time code mode that mutes the time code output when not in record:

 

Free Run Auto Mute
Functions the same as Free Run mode except timecode signal is muted from the LEMO output when the 664 is in stopped mode. This allows rec-run functionality when Rec Run mode is not suitable (e.g. Multi-camera shoots). Note that timecode signal is still output during play and play-pause modes.

 

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The 664 has a time code mode that mutes the time code output when not in record:

 

That's great, thank you!

So that being the case, the need for the relay used in Cory Allen's 788t time code hack goes away, correct?

Also, would the time code signal need to be padded for input into the iPad? Denecke have a schematic for a "iDevice" cable, but they show two versions: one with a 33k resistor and one without. How would I determine which version to use with MovieSlate and an iPad?

Lastly, it looks like 788t has a similar auto output mute mode as well, so I'm guessing it could use the same cable as the 664 would use. The Time Code Out specs for both devices appear to be identical: 1k ohm impedance, 3.0V p-p (+12 dBu).

 

 

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That's great, thank you!

So that being the case, the need for the relay used in Cory Allen's 788t time code hack goes away, correct?

Correct, that time code mode does the work of the GPIO/Relay.

Also, would the time code signal need to be padded for input into the iPad? Denecke have a schematic for a "iDevice" cable, but they show two versions: one with a 33k resistor and one without. How would I determine which version to use with MovieSlate and an iPad?

Probably a better question for Charlie Parra at Denecke

Lastly, it looks like 788t has a similar auto output mute mode as well, so I'm guessing it could use the same cable as the 664 would use. The Time Code Out specs for both devices appear to be identical: 1k ohm impedance, 3.0V p-p (+12 dBu).

 

 

Yes, the time code circuit is identical on the 6 and 7 Series boxes.

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Just to follow-up for the sake of the archives and anyone else who comes along with the same questions I had:

Remote Audio make attenuated time code cables for iOS devices, including a 5-pin LEMO version that will work with Sound Devices recorders like the 664 and 788t. You can find them at the bottom of this page:

http://www.remoteaudio.com/cables_adapters/timecode/

Thanks to Cory Allen for this information.

 

Edited by sarcanon
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