A consumer appliance with a body. A cartridge removably mounted to the body. The cartridge having a surface with a first colored region and a second colored region. A control circuit positioned within the body. A first emitter that projects a first light at the first colored region and a second light at the second colored region. A first light sensor mounted the body that sends a first signal to the control circuit based on a color of light reflected from the first colored region. A second light sensor mounted to the body that sends a second signal to the control circuit based on a color of the light reflected from the second colored region.