A Python refresher: material from Physics 298owl

Physics 398DLP data logger and GG's sample Arduino code for various devices

• ✯  Read GPS and BME680 data, and write them to the microSD memory
• ✯  Unit 1 blinking LED code
• ✯  GG's data logger schematic, February 8, 2019 version
• ✯  printed circuit board layout for February 8, 2019 version
• ✯  GG's data logger schematic, fall 2018 version
• ✯  16 x 2 LCD code
• ✯  4 x 3 keypad code
• ✯  MCP4725 DAC code
• ✯  ADXL326 accelerometer calibration code
• ✯  microSD card read/write (plain text) code
• ✯  32 kHz audio recording to binary file code, now corrected for output buffer overwrite-related problem (needs keypad and LCD
• ✯  32 kHz audio recording to binary file AND read/report the temperature read from a BME680 (Arduino code that needs keypad and LCD)
• ✯  32 kHz audio recording to binary file AND read/report BME680 readings, with VOC gas measurement disabled. (Runs faster this way!)
• ✯  Read temperature, pressure, and humidity from a BME680, but disable the volatile organic compounds gas measurement. This runs considerably faster than a version in which the gas measurements are performed.
• ✯  Python code to read an Arduino binary audio file and (optionally) write a WAV format version. I include a short snippet of the Rolling Stones recorded by my Arduino for you to practice with. Note: if your laptop complains of memory errors, try reducing the value of max_buffers from its current (very large!) value of 50,000,000.
• ✯  Arduino code to read from the GPS breakout board and set the real time clock from the GPS clock. You may want to change the program's insistence on having you enter year, month, day information from the serial monitor.
• ✯  Much better Arduino code to set the real time clock from the GPS clock. Use this program instead of the older version, above. I think it'll synchronize your DS3231 RTC so that it is within about two milliseconds of the GPS system's clock. You will need to have connected the GPS board's PPS pin to the Arduino's D43. (That requires a wire that's about a half-inch long to be soldered onto your PCB. It's a very simple patch.) The program will wait until your GPS device sees satellites, though, so do this outdoors, or someplace where there's a decent GPS signal.
• ✯  EAGLE circuit design files
• ✯  GG's Arduino code to read various sensors, taking keypad input from the user. Available functions are these:
•   ⚛noop (no operation) = ✳NOO# = ✳666#
•   ⚛display Real Time Clock value = ✳RTC# = ✳782#
•   ⚛display ax, ay, az = ✳ACC# = ✳222#
•   ⚛display battery voltage and current = ✳BAT# = ✳228#
•   ⚛measure audio power, 1 second duration = ✳AUD# = ✳283#
•   ⚛display GPS information = ✳GPS# = ✳477#
•   ⚛display temperature = ✳T# = ✳8#
•   ⚛display pressure = ✳P# = ✳7#
•   ⚛display (relative) humidity = ✳H# = ✳4#
•   ⚛display VOC reading = ✳VOC# = ✳862#
•   ⚛display infrared sensor temperature = ✳IR# = ✳47#
•   ⚛calibrate ax, ay, az = ✳CAL# = ✳225#
•   ⚛play audio tones based on keypad selection = ✳MUS# = ✳687#
•   ⚛send help information to LCD = ✳000# = ✳000#
•   ⚛altitude above sea level = ✳A# = ✳2#
•   ⚛laser range finder distance (mm) = ✳D# = *3#
•   ⚛repeat last command = ✳# = *#

Atmel microcontroller and Arduino Mega 2560

• ✯  Arduino website
• ✯  Arduino programming language reference
• ✯  Arduino programming language libraries
• ✯  Arduino Mega 2560 schematic
• ✯  Atmel 2560 manual

EAGLE schematic capture and PCB tools

• ✯  "Every Layer in Autodesk EAGLE and What You Need to Know About Them"

3D printing; construction tips and techniques

• ✯  p398DLP_UM2plus_set_nozzle.curaprofile: Cura 3.5.1 settings profile. Download and use this for a Cura slicing with a UM2+ target machine.
• ✯  Cura 3.5.1 settings I use for an Ultimaker 2+ 3D printer (a PDF file of screen shots). I find that poor adhesion of the PLA (poly lactic acid) plastic to the printer's glass build plate is the principal difficulty to be overcome. Here's what works for me: (1) Keep the glass build plate scrupulously clean, and wipe it down with 70% isopropyl alcohol (ordinary rubbing alcohol, which is a 70-30 mix of alcohol and water) before each print job. The water content is important, since there'll probably be a 100 nm thick layer of water that adsorbs to the glass surface when you wipe it down. Pure isopropanol will strip this away, and you won't have all those helpful hydrogen bonds from the water to hold the plastic to the glass. (2) Don't apply glue, masking tape, or any of the other suggested toppings you might read about (chocolate sprinkles?) to the glass. (3) Do a quick adhesion test, using this STL file, which you'll need to turn into gcode. It runs in a little less than 9 minutes on an Ultimaker 2+ with a 0.6 mm nozzle if you load the Cura 3.5.1 profile p398DLP_UM2plus_test_no_brim.curaprofile first. (4) Adjust the nozzle and build plate temperature. I find that dark colors of PLA require higher temperatures than light colors. Black, for example, works nicely with a 235°C nozzle and 65°C build plate.
• ✯  Cura 3.5.1 profile for Ultimaker 2 (not 2+)
• ✯  Cura 3.5.1 profile for adhesion tests with Ultimaker 2 (not 2+)
• ✯  Cura 3.5.1 profile for Ultimaker 2+
• ✯  Cura 3.5.1 profile for adhesion tests with Ultimaker 2+
• ✯  Breadboarding guide

Sensors and other hardware

• ✯  Adafruit Industries website
• ✯  CrystalFontz LCD
• ✯  Adafruit tutorial for their microSD breakout board
• ✯  DS3231 real time clock
• ✯  Bosch BME680 temperature, pressure, humidity, volatile organic compounds sensor
• ✯  GPS module data sheet
• ✯  GPS NMEA command description
• ✯  More GPS information
• ✯  Texas Instruments HDC1000 humidity and temperature sensor
• ✯  Melexis MLX 90614 IR thermometer
• ✯  Maxim microphone preamplifiers
• ✯  Microchip MCP4725 12-bit digital-to-analog converter

A table that includes I2C addresses for Physics 398DLP hardware...
      ...and a link to Adafruit's list of I2C addresses for their devices.

part	description	I2C address
0.1uF capacitors	for 5V bypass
10kohm	sets contrast for LCD
16 × 2 LCD	liquid crystal display
22 gauge wire	for breadboarding, various colors
3 x 4 keypad	tap tap tap
AA batteries and case	power to go
Adapter Cable	for GPS antenna
Arduino Mega 2560	microcontroller
Black cardboard box	for your breadboard
BME680	T/P/RH/VOC	0x76 or 0x77
Breadboard	for building your prototype; on loan
CR1220 batteries	batteries for GPS and RTC
digital multimeter	on loan for the semester
DRV2605L	haptic vibrator driver	0x5A
DS3231	real time clock	0x68
electret microphone	amplified microphone	analog output
EMG electrodes	Electromyogram electrodes
eye protection	on loan for the semester
Force-sensitive resistors	Just like it says
GPS Antenna	External Active Antenna
GUVA	Analog UV sensor	analog output
Haptic feedback	motorized vibrator
INA219	voltage/current sensor	0x40
L3GD20H	Triple-Axis Gyro Breakout	0x6B
LSM9DS1	accelerometer/magnetometer/gyroscope	0x1E
MCP4725	DAC, 12-bit, I2C	0x62
MicroSD card breakout	holds microSD card	SPI
MicroSD memory card	8 GB SDHC
Mini Metal Speaker	8 ohm 0.5W
MLX90614	IR thermometer	0x5A
MMA8451	±2 g accelerometer	0x1D
MyoWare	EMG muscle sensor	analog output
of/off/on/off pushbutton	battery vs. USB power
P164 GP2Y0A21YK0F	IR distance sensor	analog output
PAM8302	PWM audio amplifier	PWM analog output
Pink plastic bag	your toy bag!
PM2.5 PMS5003	airborne particulate monitor	UART RX/TX
QS-FS01	anemometers	analog output
T-slot photointerrupter	counts blades	phototransistor output
TCA9548A mux	I2C multiplexer	0x70
Tiny camera	Adafruit “mini spy camera” part 3202	MicroSD; USB
TSL2561	Digital Luminosity/Lux/Light sensor	jumper to 0x39
tweezers	on loan for the semester
ultimate GPS	cool navigation device	UART RX/TX
USB cable	talk to the Arduino
VL53L0X	Time of Flight Distance Sensor	0x29
wire stripper	on loan for the semester