Do you mean the bit that meters the paint out or the thing that shakes up the paint? I can't help you with your enquiry but there are many different systems. The metering equipment is available on ebay about £30 each+post but you would need one for each pigment and some very accurate scales and an agitator. My wife works for a car spares distributor who mixes paint and I've been in and watched while he modified some I bought which was a bit off and there are racks of tints and bases filling a whole wall all with their own meter attached. At the price on ebay there would be about £18,000 on the wall rack.
At the moment we get all our paints from a local bodyshop supplier. We just tell them what the paint code is and they mix it for us. What we want to do is be able to mix the paints ourselves thus saving us time and money. We refurbish alloy wheels and at times we have customers that come to us with light kerb damage on the wheels, where we have to take the wheel to our supplier and get them to match and mix the exact colour.
I have seen on some videos where they use a laptop and some sort of scales to get the paint that is required. Maybe the type that these mobile workshops use to repair scratches and dents on car.
they all use scales to weigh out the base ingrediants
what you have to consider is will it be economical for you to do
to have a mixing scheme the hse will state you need a storage room with proper ventilation incase a fire broke out also do you use enough paint to warrant buying all the base colours i will be an expensive outlay at first