Sparkfun ML8511 UV sensor breakout voltage output changes on a MSP430G2553 ADC10

Hello,

I bought a Sparkfun ML8511 UV sensor breakout and set it up according to this.

It kind of works / I have a weird problem: No matter the voltage (3V or 3.3V), the sensor output values change periodically very strongly:

• Closer to UV-AB source: ~1.5 to ~10.5 to ~1.5 and so on (with more steps in between) (distance of course doesn't change).
• More away from the UV source: ~0.2 to ~1.5 to ~0.2 and so on.

When I attach a 1.5V battery constant voltage source as a test, the displayed value is indeed rather constant ranging from 4.39 to 4.59, so it must be the sensor's problem?

Google-ing this problem didn't reveal any results.

I tried using A0 and (A1-A5) because of possible noise? but this unfortunately didn't help.

I'm using a MSP430G2553 and its ADC10, on a breadboard. Is this a known problem of such a setup?