May 25 2015
a arduino in a low power / battery application
needs to operate a camera.
- some checks in spec / manual show there is a remote unit / to a port at the camera, possibly just a push button with a cable to a 3.5mm jack.
but using a relay has a disadvantage,
in active state the arduino must power the output to the relay coil
so i ordered a bistable / latching relay what has to be switched
ON by pulse from one output,
OFF by pulse from second output,
because at boot the status would be unknown, a feedback to arduino input must be tested.
testing a JSL-D5N-K FUJITSU
Power relay Latching 5V 10A see here looks like coil at 5 VDC has 114 or 53 ohm ( 43 or 90 mA )
a arduino output can not drive that, so need add 2 transistors, i try 2N3904
the circuit from here