With this project I try to use as little moving parts as possible, that's why I want the candy to be ejected of the main channel by compressed air instead of a mechanical system. For my source of compressed air I will use a cheap and compact off the shelf compressor.
In that category, the airbrush compressors seem like a good fit, so I bought a Wiltec AF18-2 for about 60 euros online. This model does not come with an air tank.
It can go up to 4 BAR (60 psi) which is more than enough, but I think the throughput is too low.
An air tank would solve that problem by storing air when it is not needed (like a capacitor for electricity). This givesa more steady stream of air. There is a Wiltec model with an included tank but I already bought my compressor, so I had to make my own air tank.
For this I got a few quick fittings and a 6mm silicon tube.
I cut a hole in the cap of a plastic soda bottle and glued a straight fitting with epoxy. The joint is air tight and can probably handle more pressure than the bottle itself.
Then I just had to put the cap back on the bottle and install it on the compressor.
Next time I will play with solenoid valves.