Camera timer



To take picture the shutter need to be pressed down time to time.
On the Sony DSC-T100 I could tie a rubber band over the shutter, than it would take pictures until runs out of space.
But the pictures are not in focus anymore, most of them are out of blurry, plus I loose control when to take picture anymore.
I installed a servo next to the camera, when I press the gear down it takes a picture.
This works, but I must press the gear down while I have to fly the airplane .
I made this timer circuit.  If I switch it on, the timer takes over and the camera is taking pictures itself.
The LED is red when taking a picture, other time it is green.
Also I have a potentiometer, with that I can set the interval between pictures from 2 to 35 seconds.  This camera needs 4 seconds between pictures.
The modified transmitter looks like this
The inside
Here is a short 3.6 MB video from one of the test
Same closer
Here is a drawing from the circuit.  
Q1 transistor amplifies the output of the 555 chip.  If the 555 gives high, than the LED green side gets power.  Q2 Base is high,  Q2 Collector is low and the LED red side gets the power.  Q3 Base is low, but Q3 Collector is high.  No power goes through the Relay switch, thus the relay does not pull in.
If the 555 gives low, than Q1 Emitter is low, Q2 Base also low.  But Q2 Collector is high.  Thus the red side of the LED gets the power.  In the same time Q3 Base is high and the electricity start to flow through the transistor, causing the Emitter to became low.  Which in turn connected to the relay.  This relay is connected to the landing gear channel, when the relay pulls in gives the same result as someone pressed the gear down switch.