A small note on how to wire and connect LogicSwitch to Optipower Ultra Guard backup-device.
Because I’m sure there are people who appreciate the possibility to turn off backup-power after landing. Straight from transmitter, not from some really small button on Ultra Guard. And because LogicSwitch sale is opening any day now. Make some safety-precautions, for example unable to turn off when models main-power is connected and so on.
Pretty easy, let’s take a look on schematic:
The input on LogicSwitch is straight to receiver. (Positive lead is not used to anything, you can leave it out if you want.) Note that output needs to be “Digital Output”. Output pins used from LogicSwitch is “GND” and “OUT 100 Ω”. Note the polarity! The switch in Ultra Guard is not potential free, one higher pin is positive and lower pin is negative (GND).
Be careful when soldering cables to Ultra Guard so You don’t accidentally short the switch-pins to switch frame. Also it is worth mentioning You are most likely voiding the warranty on Ultra Guard when doing this. (I’m still hoping Optipower would make a header for external switch… wink wink…)
When ready it could look something like this:
I recommend that you secure the wires with hot-glue or similar. LogicSwitch is so small it can be put inside the heat shrink of Ultra Guard (isolate with two-side tape or similar) to make a complete neat package.
Note: I have two models of Ultra Guard, one older and one newer. One of the unit’s goes to error-mode when connecting battery to Ultra Guard. This is due small capacitor on LogicSwitch which get’s charged on first connection. Simply unplug the battery from Ultra Guard and connect it again. For some reason the other unit does not behave like this.
As with all backup solutions, hopefully one never has to really use it, now, go out and fly!