Thursday, November 28, 2019

Teabot Upgrades

My teabot was only able to remove teabags after 3 and a half minutes, but sometimes I make tea that brews longer. So I decided to add a switch to allow for the removal of the teabag at an adjustable time. The switch determines which GPIO pin, if any, is connected to the motor. If pin 9 or pin 13 is connected to the servo, then it will remove the teabag at 3 and a half minutes or 5 minutes, respectively.
I also replaced the front panel, which was made of a very thin clear plastic, with a half inch thick acrylic panel that I got from my great uncle Mike.
There were also electrical issues. The lift motor was just barely working on the 5 volt output from the Arduino. The minimum voltage for the motor was 4.8. Sometimes it would cause electrical issues such as boot looping. So I added an LM7806 to the power board so I could run the motor off 6 volts, which is right in the middle of the voltage range.
When I reinstalled the power board, there was a short circuit between one of the inputs and the positive unregulated rail, this caused the transformer to dissipate over 100 watts and overheat, so I added a dual fuse holder, with 1 amp fuses. It would also reboot at the end of the cycle  (and start pouring the water over again), so I added an ac capacitor in parallel with the contactor

clear panel and new switch







Fuse holders