remote record question

[aj4]

Hello, I would like to set up my recorder with a remote start/stop switch for recording, but I would like to use a latching type switch that only records when the switch is held on (latched, not momentary)

From reading the literature, I gather the remote record works in the following manner -

Press button and release - recording starts
Press button and release - recording stops

If the unit is tucked away so the LEDs are not visible, with the unit being repeatedly switched from record to pause via a momentary switch its quite easy to forget where you are and you end up recording when you wanted to pause and vice versa :o

what I would like to do is set it up like this in some way

Switch position 1 (short circuit) - recording starts
Switch position 2 (open circuit) - recording stops

I believe there is a 40ms anti-bounce delay from pressing the button to the recording starts, is there anything else that would be useful to know ?

I need to design a simple latch circuit to make the record switch operate as I need it, but just wondered if there were any other issues I should be aware of. For example, I assume the record starts on a logic 0(button pressed), does the circuitry then wait for a logic 1(button release) before it resets and waits for another logic 0 to stop recording ?

Apologies for the poor description, I hope you can understand what I'm asking, lol.

Ta,

Ross.

[BroussalM]

Hi Ross

To make something simple and secur to use, take the RJ-45 and use 4 wires : Led red / Led green / Remote switch / ground
It's, of course, very important to get the Leds information near your switch.
You have the description of the RJ-45 at this address

http://www.chasecam.com/forum/showthread.php?t=60

You can used a latching switch but you need to make the mouvement:

Off/On/Off > (rapidly) Start and Pause
Off/On/Off > (rapidly) Recording
Off/On/Off > (rapidly) Pause
Off/On > (stay on : On) to stop the PDR100
Off > ( Back to : Off ) to restart at your " 0 " set-up switch.

As you have brought the leds by the wires near your switch, you'll know at any moment where you are, Rec or Pause or stop.
Simple !

Hope it's help you
Regards
Michel Broussal

[Mark]

Using the built-in interface sound like a recipe for disaster if you ever screw up the latching.

I'd suggest you use the LAN-C interface. I don't know of any LAN-C remotes that record only when the button is held down (dead-man's stop?) but I'm sure there's one around if you look hard enough.

Since I like DIY stuff, I'd suggest you take a look at a LAN-C controller that you can build and program yourself.

You can make something like this controller (http://www.instructables.com/id/Cheap_PIC_controlled_Helmet_Camera_using_Sony_LANC/) at Instructables. Obviously, you would remove one of the swtiches, make the other latching and tweak the code to continually check the remaining switch. When the switch transitions one way, send a record command. When it transitions the other way, send a stop. What could be easier? :)

Okay, I took a look at the source code and it's assembly. A quick search didn't unearth any C source code, but hopefully the assembly doesn't need to be tweaked that much. It also helps that it's commented well.

[aj4]

Thanks for the suggestions guys :cool:

Not really keen on the Lanc method, although I am thinking of building the one you suggested for my Sony camcorder now, lol.

I think I might have came up with a method, depending on how the pins 4&5 work. I know shorting them together activates record, so am assuming one of the pins is ground and the other is at 5v or logic 1.

All I need to do is build a small PIC so that when the button is pressed the PIC sends a short logic 0 for 100ms followed by a logic 1 to start the recording. Then when the button is released it sends the same again for the stop command.

Can anyone confirm whether the remote signal line operates on a logic 1 being pulled to logic 0 ? I think I really need one of the guys who designed it to answer before I start ripping it apart and investigating, lol :D

[Mark]

Yes, I'm pretty sure that it's pulling one of the IOs to ground to simulate hitting the power button. That's what I do to turn on my PDR with a Parallax propeller microcontroller.

The problem with having a PIC the way you suggest is that you need to track the state. I guess it's not that big of a deal, it's not like the PIC and PDR are going to get out of sync, are they?

Me, I'm paranoid so if you're planning on connecting a PIC to the remote port anyway, then I'd put in code to interpret the red and green LEDs and get a read of the actual PDR state. I believe that the red LED is on (and the green blinks) when the device is recording and the green LED is staedy when it's ready to record, blinking green when starting up and I forget what it is when in a menu screen. Obviously, verify for yourself on pins 3 and 6.

You might even be able to read the power state on the PDR by checking the Vdd on the remote port. Maybe Randy can tell us if Vdd is switched with the power state of the PDR. Me, I just check the power output to the camera since I'm hooked in to that port too.

[aj4]

Thanks again Mark, I am going to try using a very simple circuit to detect whether the red led is on or not. Something along the lines of,

Button pressed, is red led on ? yes=then do nothing, no=send low pulse to start recording
Button released, is red led on ? yes=send pulse to stop recording, no= then do nothing
Repeat

I think a 100ms low pulse should do to cover the switch antibounce delay and hopefully any false triggers or unknown states will be corrected within a cycle or two if it gets 'confused'.

It will probably take a bit of fiddling with the timing etc, for example I don't know how long it takes for the red led to come on once record is pressed, but I assume its pretty instantaneous (quicker than 100ms)

Ross.

[RandyChase]

Hi,

Yes the recorder operates based on the signal being pulled low. There is a 40ms anti-bounce in there.

The VDD output should not be used, but yes, when the unit is on, the output is then active.

I would recommend using the RED and GRN signal drivers for status.

[aj4]

thanks Randy, much appreciated.