|Subject:||Re: [Paparazzi-devel] 5v pulse required for CHDK on Lisa/M2|
|Date:||Fri, 2 Nov 2012 09:36:13 -0300|
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.
|[Prev in Thread]||Current Thread||[Next in Thread]|