A DIY Arduino-based camera timelapse remote controller, you can set your desired start & end time and date. Since we're using RTC for timing, your phone can be offline during the timelapse.
MAIN PART
1) Arduino nano
2) Tiny RTC (real-time clock)
3) Bluetooth module
4) Remote cord for you camera model
You can find the parts here: http://www.hksupport.hk
Download the Arduino sketch
https://drive.google.com/open?id=0B9aOeR9DBGoxOW1ITHRIVXZ0Tlk