We are currently building this:

http://www.youtube.com/watch?v=jHc5v-lulGY

This will first allow simple, traditional profiles, with adjustable waiting times, different delivery slopes (constant flow, linear, logarithmic or exponential rises/falls). Later, when connected to vAg sensor and PC, more advanced runs will be possible.

We have made designs for mechanical part and soon we'll build it. Coming soon..!