There are two types of dispensers. Not very DIY friendly air-pressure-controlled dispensers and motor-controlled dispensers. In this project I designed a Motorized dispenser which uses a screw to to convert the rotational motion into linear motion.
Most of the parts which are needed to complete the project can be 3D printed. Parts are designed to fit with standard solder paste syringes. feel free to change them however necessary. 3D model files can be found on Thingiverse - Solder Paste Dispenser
An attiny85 microcontroller is used to dive the stepper motor through a ULN2003A Darlington transistor array. Firmware for the microcontroller - GitHub Repository
Schematics and PCB layout - EasyEDA - Solder Paste Dispenser