Panometer

A sourdough starter monitor. A distance sensor measures how much the starter has risen and plots its growth over time on a small OLED display embedded in a wooden lid sitting on top of the jar. Prototyped on a Raspberry Pi in Common Lisp, then rewritten in C and compressed onto an Arduino.

Arduino

Schematic

Setup

# install arduino-cli
curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | sh

# install core for nano
arduino-cli core update-index
arduino-cli core install arduino:avr

# compile and upload
make
make upload # or upload_old depending on the version of the bootloader

TODO

• Add hour markings on the graph
• Screen refresh rate slows down with increasing number of samples - investigate and optimize

Raspberry Pi Zero

Schematic

Setup

• Download and install Raspbian Stretch Lite

• Enable SSH

touch /Volumes/boot/ssh

• Enable and configure WiFi

country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
  ssid="my SSID"
  psk="my password"
}

• Install DHT11 driver
• Install Python 3

sudo apt-get install python3

• Install vl6180 driver
• Enable I2C

sudo raspi-config

• Install Common Lisp (Clozure - armcl)

sudo apt-get install libiw-dev armcl

• Set up a daemon

cp panometer.service /etc/systemd/system/
sudo systemctl enable /etc/systemd/system/panometer.service
sudo systemctl start panometer.service