Multirotor Quick Tips: KK2.0/KK2.1 constantly beeping

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I have been refitting one of the first quads I built with a KK2.0 and some LED lights for evening/night flying now the nights are getting darker. When I powered on the craft for the first time it started beeping and wouldn't stop! It took me a few minutes to figure it out.
Here is the what's causing it and how you can fix it.
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Happy flying!
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