I have designed a pen holder to turn my printer into a drawing machine which fits the swappable hot end I have designed a while ago https://www.thingiverse.com/thing:3547740 Unlike most pen holders I have seen, this one is activated using a 12V solenoid. This way it is possible to control it quite similar to controlling a laser cutter. The solenoid is, like the laser cutter, controlled by the part end fan connection. This worked as well as I could have hoped for!
Please consider buying me a coffee if you liked it or helped you :) http://ko-fi.com/properprinting/