Sweet daemon for pairing and control of the Bitcoin-enabled candy dispenser

sweetd is the daemon process running on the Bitcoin-enabled candy dispenser. It manages pairing and control, which is used by the Candy Dispenser app:

• 📱 Candy Dispenser iOS app
• 📱 Candy Dispenser Android app coming in the future

The sweetd program offers the following features:

• 🍬 Control of the motor for dispensing candy
• 📳 Control of the buzzer for user feedback
• ☝️ React on events from the touch sensor
• 🔵 Pair through Bluetooth
• 🌐 Set up Wi-Fi on candy dispenser
• ⚡ Dispense candy on payments from remote lnd node
• 💅 Customize name of your dispenser
• 🔄 Update itself through app
• ⚙️ Ensure all system configs are made

Download the pre-built binary for your system from the GitHub releases page.

• ⬇️ Download sweetd

Extract and open the downloaded archive, then run sweetd.

The sweetd program's source code is split into small modules:

• 🔌 api - REST api for remote management of the dispenser
• ⚙️ app - website for managing the dispenser
• 🍬 dispenser - orchestrator for everything the dispenser does
• ⚡️ lightning - controller for configured Lightning nodes, remote and local
• 🔩️ machine - hardware controller for the touch sensor, motor and buzzer
• 📶 network - network subsystem that handles Wi-Fi discovery and connectivity
• 🤹‍ nodeman - node manager
• 🧅 onion - Tor onion service conveniences and .onion address generation
• 📲 pairing - pairing controller for BLE pairing
• 💵 pos - point-of-sale website that creates invoices
• 🛑 reboot - methods for rebooting and shutting down the system
• 📁 sweetdb - persistent database manager
• 📃 sweetlog - logging middleware for intercepting logs
• 🔖 sysid - methods for determining a system-specific id
• 🔄 updater - update subsystem that controls system updates

By default, sweetd stores all data to ./data. You can easily override this location:

sweetd --datadir=/data/sweetd

Currently, the sweetd program is only tested and executed on a Raspberry Pi. Running the executable with no options is the same as providing the following options:

sweetd \
  --machine=raspberry \
  --raspberry.touchpin=25 \
  --raspberry.motorpin=23 \
  --raspberry.buzzerpin=24

You can also mock the underlying machine with the following option:

sweetd \
  --machine=mock \
  --mock.listen=localhost:5000

With this option, you can fake touches by sending simple HTTP requests to the mock machine:

curl http://localhost:5000/touch/on
curl http://localhost:5000/touch/off

sweetd exposes a gRPC API. It can be used to configure the Wi-Fi network that the candy dispenser connects to, personalize it and change settings.

By default, the API server listens on 0.0.0.0:9000. This can be changed with the following option:

sweetd --listen=localhost:9000

It's also possible to specify multiple --listen options and listen to multiple interfaces at once.

At the moment, the only app pairing mechanism is through a Wi-Fi hotspot that is created by the sweetd program.

This feature needs to be activated first:

sweetd --ap

Make sure that the following dependencies are installed when running the access point mode:

hostapd wireless-tools wpasupplicant dnsmasq iw

The access point is configured with the below defaults. Any of these can be changed to your needs.

sweetd \
  --ap \
  --ap.ip=192.168.27.1/24 \
  --ap.interface=uap0 \
  --ap.ssid=candy \
  --ap.passphrase=reckless \
  --ap.dhcprange=192.168.27.100,192.168.27.150,1h

This will create a Wi-Fi network called candy with the passphrase reckless. An app will connect to that network for pairing and use the gRPC api that is provided by the sweetd program.

go get -d github.com/the-lightning-land/sweetd

cd $GOPATH/src/github.com/the-lightning-land/sweetd

go build

./sweetd

The tool goreleaser can automatically sign the release and upload it to GitHub.

git tag -a v0.1.0 -m "Release name"

git push origin v0.1.0

goreleaser --rm-dist