Week Goals

Waseh: Goal for this week was to understand the working of the ESP8266 and be able to communicate with the other ESP8266. We had also planned on developing the software for communicating via the PIC.

Ian: Finish mechanical design and fabrication (motor mounts, etc.).  Prototype circuit on breadboard for the shade controller.

Worked on this week

Waseh: Communicating with the ESP8266 via usb_serial interface. Developed understanding of the networking requirements. Setting up communication with the PIC and allowing the PIC to automatically program the ESP8266 and communicate using that with the webpage.

Ian: Modeled shade controller in Inventor.  Laser-cut and assembled parts.  Wired a Hall Effect sensor (soldered leads as well as a decoupling capacitor across the power supply to the sensor itself).  Tested motor drive system by using the signal generator to create the PWM signal for the servo.  Added multipole ring magnets to the drive pulley and tested hall effect sensor using the oscilloscope.  Tests generally went well, though there were some surprises (see challenges section).  Most notably, the motor seems to be able to generate sufficient torque to drive the shade without pulley slippage.

Challenges

The Hall Effect sensor seems to work slightly differently than expected.  Firstly, it is less sensitive than would be ideal, and needs to be closer to the magnet than our design currently places it.  This is not too difficult, but does require some hardware modifications.  Secondly, it’s definition of “high” seems to be ~0.7V.  It is unclear at the moment whether this is due to incorrect wiring or because it is simply how the part works.  Regardless, either the associated electronics need to be fixed, or additional processing hardware is needed (in this case, probably an op-amp) to be able to feed this signal into the PIC.

Understanding the working of the ESP took longer than expected and so did the library implementation. This helped us understand the system better though so it will come in handy.

Goals for next week

Ian: Fix Hall Effect sensor and/or design appropriate conditioning electronics.  Move control from the signal generator to the PIC itself.  Implement simple shade open/close commands via buttons on the shade controller (including speed feedback control and endpoint detection).

Waseh: Development of the software for interfacing with the light sensor and communicate control signals to the other ESP8266 using the PIC. Also to develop ability for motor-control ESP to read and reply to the main controller.