(c) 2022 Bly Lee d.b.a. WonderGap, LLC
This code is licensed under MIT license
Solely intended for use at Science Gallery: Hooked in ATL, GA in 2022
Software run on Raspberry Pi 4B+ and Arduino Mega2560 and all LEDs are WS2811s
When running strawberrycough.py, be sure to run with root permissions as the NEOPIXEL library cannot function correctly without them:
$ sudo ./strawberrycough.py
When running northernlights.py, it is not necessary to run with root permissions:
$ ./northernlights.py
The Arduino program, stardawg.io should be flashed to the Ard memory from a desktop/laptop computer with the Ard IDE, then connected via USB3.0 to the Raspberry Pi unit.
Should you have issues running the python scripts with the terminal commands above, try:
$ chmod +x filename.py
Strawberrycough.py acts as the showrunner for the in-booth guest experience, controlling all lighting, audio, and DC motors for marble conveyance. Please note, at this time, strawberrycough.py does not support real-time tracking of guest input for use as a data stream for the showcase display. While this functionality could be implemented in a v2.0, it will require the allocation of more resources (predominantly time and money).
GPIO Pinout (using BCOM/Board numbering)
GPIO 26 - control for YES button light relay (OUTPUT)
GPIO 20 - control for START button light relay (OUTPUT)
GPIO 25 - control for NO button light relay (OUTPUT)
GPIO 21 - DOUT for LED lighting (OUTPUT)*
GPIO 16 - START button (INPUT)
GPIO 19 - YES button (INPUT)
GPIO 13 - NO button (INPUT)
GPIO 06 - control for INTERIOR YES DC motor relay (OUTPUT)
GPIO 05 - control for INTERIOR NO DC motor relay (OUTPUT)
GPIO 12 - control for EXTERIOR YES DC motor relay (OUTPUT)
GPIO 07 - control for EXTERIOR NO DC motor relay (OUTPUT)
* While GPIO 18 is the standard PWM OUT for lighting control on the Rapsberry Pi, this PWM channel is shared by the 3.5mm audio jack i.e. it is not possible to play audio over the 3.5mm jack AND control lights at the same time. For this reason, the lights have been switched to GPIO 21 which operates on an entirely separate PWM channel and causes no interference.
WS2811 Wiring Instructions
The NEOPIXEL library on the Raspberry Pi can only handle one strand object at a time i.e. it is not possible to control two separate strands of lights. To workaround this, directly connect 10 question indicator lights to the DOUT on the RPi then daisy-chain the strand to the wheel of accent lights. All the lights can then be treated as one strand where
strand[0 ... 9] controls the question indicator lights and
strand[10 ... end] controls the strand of lights.
RPi GPIO 21 ---> DIN question indicator LED[0] ... LED[9] ---> DOUT ---> DIN strand/wheel of accent lighting
Northernlights.py acts as the RTC handler and serial communicator to the Arduino to facilitate the showcase, solenoid-powered marble drop. Northernlights.py should ALWAYS be running in the background. Every hour, on the hour, a signal is sent from the RPi to the Arduino (running stardawg.ino) causing the Arduino to power the solenoids as needed for the drop (see stardawg.ino section below).
The serial communication to the Arduino is conducted via USB3.0 (tty/ACM0). If encountering issues with the communication protocal, ensure UART is configured correctly and the user has the appropriate hardware permission to access the required port. See helpful documentation here and here for troubleshooting.
Stardawg.ino acts as the solenoid controller for the showcase, solenoid-powered marble drop. Upon recieving a serial signal from the RPi northernlights.py RTC manager, stardawg begins a drop sequence for each question (two solenoids per question). The distribution of the drop (ratio of yes:no) can be altered in the stardawg.ino program by altering the third argument in the void drop(int relayYES, int relayNO, int instance) function call.
The program assumes 36 marbles per drop. Considering an equal distribution of questsions answered (i.e. everyone who does the experience must answer all 9 questions to complete the experience), that leaves 4 marbles per question (36/9=4). With that in mind, there are 5 different scenarios per question per drop.
- Scenario 1: 25% YES, 75% NO
- Scenario 2: 75% YES, 25% NO
- Scenario 3: 50% YES, 50% NO
- Scenario 4: 100% YES, 0% NO
- Scenario 5: 0% YES, 100% NO
With the current software architecture, real-time tracking from the RPi is not available at this time. However, the following solution should still provide a fantastic experience and ensure the data remains accurate even if the sample size from the community survery remains too small to be statistically accurate.
Running a Pi Headless
Establishing Serial Communication btwn RPi and Ard
- https://roboticsbackend.com/raspberry-pi-arduino-serial-communication/#What_is_Serial_communication_with_UART
- https://roboticsbackend.com/raspberry-pi-hardware-permissions/
- https://www.arduino.cc/reference/en/language/functions/communication/serial/read/
- https://arduinogetstarted.com/reference/serial-available
RPi GPIO Event Detection, Debouncing, and Callback Threads
- https://raspi.tv/2013/how-to-use-interrupts-with-python-on-the-raspberry-pi-and-rpi-gpio-part-3
- https://sourceforge.net/p/raspberry-gpio-python/wiki/Inputs/
- https://raspberrypihq.com/use-a-push-button-with-raspberry-pi-gpio/
- https://shallowsky.com/blog/hardware/buttons-on-raspberry-pi.html
Controlling NEOPIXELs/WS2811s from the RPi
- https://learn.adafruit.com/neopixels-on-raspberry-pi/python-usage
- https://learn.adafruit.com/neopixels-on-raspberry-pi
- https://forums.raspberrypi.com/viewtopic.php?t=260962
Audio Output in a World where Omxplayer is Deprecated
Enabling an RTC on RPi
- https://maker.pro/raspberry-pi/tutorial/how-to-add-an-rtc-module-to-raspberry-pi
- https://thepihut.com/blogs/raspberry-pi-tutorials/17209332-adding-a-real-time-clock-to-your-raspberry-pi
- https://www.switchdoc.com/2014/08/raspberry-pi-python-library-ds3231/
- https://www.raspberrypi-spy.co.uk/2015/05/adding-a-ds3231-real-time-clock-to-the-raspberry-pi/
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