/diy/ - Do It Yourself

Started a thread about it but I figure I'll copy it over here as well since I love you guys:

If you don't know what Soylent is already, it's a powdered food substitute. Measure it out with a spoon, mix it up, drink it for lunch. I want to make a machine that will automate the measuring, and maybe the mixing later on.

My plan is to have a small 8 segment display and a few buttons to allow a certain number of calories of Soylent to be selected. Once the selection is made, the machine pours the powder onto a scale until the right weight is on it, based on the nutrition information. Typically this is around 109g for one meal, which has a volume of half a cup or so.

The electronics side will be done with a PIC microcontroller, some basic IO stuff, and pressure sensors to measure weight. The main issue is going to be slowly dispensing powder. The existing powder dispensers I've seen are for biomedical companies who need microgram precision and are way outside my budget. So my thought is to use something like the food dispensers in the picture, and have the crank be attached to a motor. Issues that I can foresee with this are:
>powder dispensed in too granular of a quantity, e.g. one compartment of the waterwheel-like mechanism holds 30g, can't dispense a partial compartment, so I'll be over- or undershooting
>hard to attach the motor, since I'm not a mechanical guy

Anyone have any thoughts? Are my fears unfounded? Is there a better way?

If you don't know what Soylent is already, it's a powdered food substitute. Measure it out with a spoon, mix it up, drink it for lunch. I want to make a machine that will automate the measuring, and maybe the mixing later on.

My plan is to have a small 8 segment display and a few buttons to allow a certain number of calories of Soylent to be selected. Once the selection is made, the machine pours the powder onto a scale until the right weight is on it, based on the nutrition information. Typically this is around 109g for one meal, which has a volume of half a cup or so.

The electronics side will be done with a PIC microcontroller, some basic IO stuff, and pressure sensors to measure weight. The main issue is going to be slowly dispensing powder. The existing powder dispensers I've seen are for biomedical companies who need microgram precision and are way outside my budget. So my thought is to use something like the food dispensers in the picture, and have the crank be attached to a motor. Issues that I can foresee with this are:
>powder dispensed in too granular of a quantity, e.g. one compartment of the waterwheel-like mechanism holds 30g, can't dispense a partial compartment, so I'll be over- or undershooting
>hard to attach the motor, since I'm not a mechanical guy

Anyone have any thoughts? Are my fears unfounded? Is there a better way?