This is a standard RSI indicator. It changes the background color to green if the RSI reading is greater than the RSI bullish value and it changes to red if the RSI is below the RSI bearish value. It will turn black for values between RSI bullish value and RSI bearish value.
You can tweak it to your liking, for example if you'd like to detect long only trades that are above 30 then you set RSI bearish value to 0 and RSI bullish value to 30 and it will only get long signals.
P.S More confirmation indicators will be necessary