[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Paparazzi-devel] 5v pulse required for CHDK on Lisa/M2

From: Hector Garcia de Marina
Subject: Re: [Paparazzi-devel] 5v pulse required for CHDK on Lisa/M2
Date: Fri, 2 Nov 2012 09:30:10 +0100

Agree with the last solution of Christophe. It would be desirable using an optocoupler for keeping cleaner the GND for the analog signals especially.

On Fri, Nov 2, 2012 at 9:07 AM, Christophe De Wagter <address@hidden> wrote:

Use e.g. a 2k to 20k Ohm resistor connected from USB+ to 5Vusb to pull it up. Use any N-MOSFET transistor (e.g. bss138) with its Gate to any paparazzi IO pin, its Source at Ground and it's drain at the USB+ pin, pulling it to zero when the io pin in paparazzi is higher than 0.7 volt.

If you have no Fet but have a bipolar NPN transistor around (like a bc547) then you just need 1 extra resistor of about 10x more ohm in between the paparazzi board and the NPN.

Another solution we use most of the time is a bipolar optocoupler switch instead of a MOSFET. Then there are no copper connections between the noisy camera ground and the autopilot/GPS/modem ground for optimal telemetry and gps signals.

On Nov 2, 2012 12:27 AM, "Marc Schwarzbach" <address@hidden> wrote:
Hi Gerard,

since there is only very low current involved (measured) I connected the USB + line to 5V and the - line to an IO, using it as drain... Did this on a LPC based board. Not sure if I used a resistor, did that some time ago and now it´s deep inside the plane.

It has been working many flights triggering my CHDK camera now.
Probably not a "correct" solution and not sure if it works with the STM in the LISA.

Of course, I also had to reverse the logic in the dc_cam code...

If you find a solution, please post, anyway!



-------- Original-Nachricht --------
> Datum: Thu, 1 Nov 2012 19:22:40 -0300
> Von: Gerard Toonstra <address@hidden>
> An: address@hidden
> Betreff: [Paparazzi-devel] 5v pulse required for CHDK on Lisa/M2

> Hi all,
> I think I'm nearing the point where I can start some test flights with my
> setup.
> I'd like to use a camera to take pictures. In my case that's a Canon with
> CHDK extensions.
> When the software detects 5V at the USB port, it triggers a picture to be
> taken.
> I'm connecting this to one of the ADC's, but the voltage is 3.3v and not
> enough to trigger
> the camera. I've verified this using a 3.3v supply from an arduino. So I
> definitely need a higher
> voltage.
> Is there any other pin I could use that does output 5v, which is
> configurable in the dc_cam module,
> or can this only be solved by inserting a level shifter?   If a level
> shifter is required, what
> are recommended components / boards?
> Regards,
> Gerard

Paparazzi-devel mailing list

Paparazzi-devel mailing list


reply via email to

[Prev in Thread] Current Thread [Next in Thread]