Abstract: A controller for use in a material dispensing system having a first material inlet, a second material inlet, a distribution outlet, a first material container and a second material container. The first material container has a first container parameter and can contain an amount of a first material. The second material container has a second container parameter and can contain an amount of a second material. The first material container can provide the first material to the first material inlet, whereas the second material container can provide the second material to the second material inlet. The controller includes a device and an output device. The device is arranged to receive the first material and to receive the second material. The device can provide a first signal based on the first material and can provide a second signal based on the second material. The output device can provide an output signal based on the first signal and the second signal.