I just picked up a 2013 A20 and am adding surf gates onto it.
I wrote arduino code to automate the actuators via GPS speeds and shared it on github incase anyone wants to check it out.
Source:
https://github.com/jonthompson/surfgateFor a basic version for <$50 you can put together the control system -- obviously the tabs/actuators are another $500+
The "simple" version that is up makes use of:
1 Arduino mega ($10 @ Microcenter)
1 GPS module w/antenna $25 -
https://www.amazon.com/dp/B01MRNN3YZ/re ... UTF8&psc=11 L298N module for a simple H bridge to control actuator relays - $7
https://www.amazon.com/Diymall-Module-S ... 00NJOTBOK/ (These JUST control the relays, NOT the high draw actuators - this was to keep it simple and avoid having to solder anything custom)
3x momentary LED backlit push buttons to control modes ($5 off ebay.)
Then:
Add standard marine relays + lenco actuators (~$170 each) and make some tabs - and you've got a custom GPS speed controlled surfgate
Basic features: 3 buttons (surf left, surf right, off) - tabs automatically deploy at set speeds (IE: >7mph and <14mph.) If you hold the buttons for a second it enters "override" mode to force deploy of that tab.
I have a more complex version that has an OLED screen + wifi module for phone control/settings via app + RF control for a custom surf band that I'll share there as well once i clean the code up and document it some.
If anyones interested in adapting this on their boat let me know - I have a full wiring diagram I'll share on the github project as well!