zultron/goldibox repository overview

⁠Goldibox. Not too hot, not too cold.

The Goldibox is an insulated box that maintains temperature using a thermoelectric device and a controller. Originally conceived to incubate biological organisms that thrive best within a particular maximum/minimum temperature range, it can both heat and cool to avoid extremes, but still allow variability within a habitable "Goldilocks zone": not too hot, not too cold, but just right.

The Goldibox's smart controller exposes a remote, network-connected graphical interface for setting temperatures, checking current state, and viewing history through time series graphs. Anyone may modify the open-source control to add new features.

This is currently a work in progress, and not all the features discussed here are ready.

⁠Time series graphs

A sample time series graph with elements explained:

• Areas: The maximum/minimum temperature is set by the user
  • Red (1): Too hot
  • Blue (2): Too cold
  • Green (3): The "Goldilocks zone," just right
• Curves: Internal and external temperatures
  • Green (4): Internal temperature; Peltier junction off
  • Red (5): Internal temperature; Pealtier junction heating
  • Blue (not shown): Internal temperature; Pealtier junction cooling
  • Black dashed (7): External temperature
• Stats: Percent of time Peltier junction is...
  • Heating (8)
  • Cooling (9)

⁠Components

The Goldibox is based on a portable fridge. These use a Peltier junction⁠, which can be switched from a cooling element to a heating element merely by reversing the voltage. They are also small, light and inexpensive, and can be found on eBay for about $40; search for "portable fridge cooler warmer 110V".

The Goldibox controller, a tiny PocketBeagle⁠ computer, fits in the cramped space next to the Peltier junction fan and heat sink. This small computer has the analog and digital interfaces to control the hardware, and runs Debian and the control software. They sell for about $25 through official distributors, and also need a $10 micro SD card for the OS, a $3 DC step-down converter to 5VDC power from the 12VDC fridge power supply, and a $5 USB type A breakout module⁠ and $10 USB WiFi adapter for networking.

The control functions come from the Machinekit⁠ software and its configuration in this repository.

The fridge is fitted with control electronics: thermistors and circuitry sense temperature; an H-bridge switches the Peltier junction between cool, heat and off; a MOSFET switches the fan on and off; and a DC-DC step-down converter provides 5VDC power for the PocketBeagle. These are small enough to easily fit under the rear cover of the fridge next to the power supply and Peltier junction. The H-bridge, MOSFET and DC power converter can be found integrated in pre-assembled modules, and all parts are inexpensive and readily available. Search for "L298N motor driver module," "Mosfet Arduino module," "DC step-down converter" and "10k thermistor" on eBay, all around $5-$8. The sensor resistors and capacitors are inexpensive if not already in one's junk box. Also, a piece of Thermagon 6100 heat-conductive pad efficiently conducts temperature from the fridge to the internal thermistor. The electronics are easily assembled with pre-assembled header wires and a little soldering; heat-shrink tubing and custom-crimped connectors improve appearance.

⁠Running

Follow the instructions at machinekit.io⁠ to download and install a mini-SD card image with Machinekit.

Log into the BeagleBone, clone this repository, and cd into the repository directory.

Run the HAL configuration:

./goldibox.hal

Control the goldibox from the command line:

# Set goldibox min, max and hysteresis params
./set.sh 15 30 2
# Disable/enable the goldibox without shutting down
./set.sh disable
./set.sh enable
# Shut down the goldibox
./set.sh shutdown

There is also a simulator configuration that can be run from Docker:

# Build Docker image
docker/qqvcp.sh build
# Run Docker container
docker/qqvcp.sh
# Start syslog, dbus and avahi services
sudo /etc/init.d/rsyslog start
sudo /etc/init.d/dbus start
sudo /etc/init.d/avahi-daemon start
# Run simulator
./goldibox-sim.hal
# Set simulated outdoor temp
./set.sh setsim 35

⁠Installing the PocketBeagle

FIXME

https://eewiki.net/display/linuxonarm/PocketBeagle⁠

minicom -D /dev/ttyACM0
ssh [email protected]
pass:  temppwd

sudoers: Don't require passwd for sudo and admin groups UNSAFE

sudo sed -i /etc/sudoers.d/admin \
    -e '/^%admin/ s/ALL=.*$/ALL=(ALL:ALL) NOPASSWD: ALL/'
sudo sed -i /etc/sudoers \
    -e '/^%sudo/ s/ALL=.*$/ALL=(ALL:ALL) NOPASSWD: ALL/'

Resize fs:

• https://elinux.org/Beagleboard:Expanding_File_System_Partition_On_A_microSD⁠
• Use fdisk to delete & recreate part with same start sector
• Reboot
• Resize rootfs with resize2fs /dev/mmcblk0p1

From http://jpdelacroix.com/tutorials/sharing-internet-beaglebone-black.html⁠ On host side:

sudo iptables -t nat -A POSTROUTING \! -o enx60640561b61f -s 192.168.6.2 -j MASQUERADE
sudo iptables -A FORWARD -i enx60640561b61f -j ACCEPT
sudo iptables -A FORWARD -o enx60640561b61f -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

On bb side:

sudo ip route add default via 192.168.6.1 dev usb1

# Clear root passwd
sudo sed -i /etc/shadow -e 's/^root:[^:]*:/root:*:/'

# Time zone
sudo ln -sf /usr/share/zoneinfo/America/Chicago /etc/localtime

# Kernel https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#4.9.x-ti
sudo /opt/scripts/tools/update_kernel.sh --ti-rt-channel --lts-4_9

wget -O /tmp/[email protected] http://deb.mgware.co.uk/[email protected]
sudo apt-key add /tmp/[email protected]
echo "deb http://deb.mgware.co.uk stretch main" | sudo tee /etc/apt/sources.list.d/
sudo apt-get update

sudo apt-get install emacs-nox
sudo apt-get install linux-image-4.11.12-bone-rt-r3
sudo apt-get install machinekit-rt-preempt
sudo apt-get install git
sudo apt-get install lsb-release
sudo apt-get install usbutils wireless-tools connman
sudo apt-get install avahi-daemon
sudo apt-get install python-rrdtool

sudo connmanctl agent on
sudo connmanctl enable wifi
sudo cat \
    > /var/lib/connman/wifi_48022ae12503_5a756c74726f6e40686f6d652d32_managed_psk \
    <<EOF
[wifi_0013ef2a079b_5a756c74726f6e40686f6d652d32_managed_psk]
Name=Zultron@home-2
SSID=5a756c74726f6e40686f6d652d32
Frequency=2422
Favorite=true
AutoConnect=true
Modified=2017-10-16T19:50:11.699608Z
Passphrase=$WIFI_PASS
IPv4.method=dhcp
IPv4.DHCP.LastAddress=192.168.7.157
IPv6.method=auto
IPv6.privacy=disabled
EOF
sudo chmod -x /opt/scripts/boot/autoconfigure_usb[01].sh
sudo sed -i /etc/network/interfaces -e '/eth0/ s/^/#/'

# Configure GPIOs low on boot
sudo dtc -O dtb -o /lib/firmware/pb_goldibox-00A0.dtbo -b 0 -@
pb_goldibox.dts
echo dtb_overlay=/lib/firmware/pb_goldibox-00A0.dtbo | sudo tee -a /boot/uEnv.txt

⁠Web interface

This is just beginning development and does nothing interesting yet.

# Build the Docker image
docker/qqvcp.sh build

# Build the AND demo
docker/qqvcp.sh anddemo-build

# Run the AND demo
docker/qqvcp.sh anddemo
# ...in debug mode
DEBUG=5 MSGD_OPTS=-s docker/qqvcp.sh anddemo