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Welcome to the Excellentea wiki!
This wiki provides a description of the hardware and software characteristics behind the RaspberryPi-powered tea maker, "Excellentea".
The hardware required for this project include electronic components for circuit implementation and the components used to build the body of the tea maker. The main components required are listed below:
- 1 Raspberry PI microcontroller board (tested on version 3 Model B)
- 1 Stepper motor (MIKROE-1530)
- 1 Digital temperature sensor (ds18b20)
- 12V DC power supply
- 1 heating element (12V) (B004O8BGXE)
- 1 tea infuser
- 1 reed float sensor (59630)
- 2 18-pin through hole socket (ED18DT)
- 2 Darlington transistor array (ULN2803A)
- LCD
- 2 N-channel logic-level MOSFET (FQP30N06L)
- MOSFET heat sink (507222B00000G)
Circuit schematic:
- 2 side panels
- 1 back panel
- 2 front panels (one of which includes a cut for the LCD)
- 2 motor support blocks
- 4 cover panels used for top and bottom (one includes a cut for the tea strainer)
- 1 motor shaft (3D printed)
All parts were designed in Solidworks. Unless otherwise stated they were laser cut and made of perspex. The 3D printed component is made of PLA.
Engineering drawing of 3D printed part:
https://github.com/GlasgowTeam3RTEP/Excellentea/blob/master/CAD%20drawings/3D_printed_part.PDF
Engineering drawing of laser-cut parts:
https://github.com/GlasgowTeam3RTEP/Excellentea/blob/master/CAD%20drawings/Laser_cut.PDF
The tea maker will be assessed whether it can successfully prepare tea within an acceptable time interval (<20 min), by following the brewing temperature and time for the selected type of tea. A good communication between the web interface and the machine should be established.
The data flow from the hardware to the web interface is illustrated in the data flow diagram:
https://github.com/GlasgowTeam3RTEP/Excellentea/blob/master/Images/Dataflow.png
The web interface interacts with the RPI through the server. When the user activates the web interface the RPI checks the input from the float switch to check whether there is water so that it prompts the user to proceed with parameter selection. Then the parameters are send from the web interface to the RPI which in turn activates the heating element. The digital temperature sensor communicates with the RPI using 1-wire communication protocol, sending information on the temperature of the water.
The workflow is illustrated below:
https://github.com/GlasgowTeam3RTEP/Excellentea/blob/master/Images/Program_flow.png
