sweetd

🔌 sweetd

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

Intro

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 Wi-Fi hotspot
• 🔵 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

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

• ⬇️ Download sweetd

Extract and open the downloaded archive, then run sweetd.

Configure data directory

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

sweetd --datadir=/data/sweetd

Configure machine access

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

Configure the sweetd API server

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.

Enable Wi-Fi hotspot pairing

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.

Installation

curl -LO https://github.com/the-lightning-land/sweetd/releases/download/v0.1.0/sweetd_0.1.0_linux_armv6.tar.gz

tar xfvz sweetd_0.1.0_linux_armv6.tar.gz

rm sweetd_0.1.0_linux_armv6.tar.gz

sudo mv sweetd_0.1.0_linux_armv6/sweetd /usr/local/bin/

sudo chown root:staff /usr/local/bin/sweetd

sudo echo "denyinterfaces uap0" >> /etc/dhcpcd.conf

sudo curl -L -o /etc/init.d/sweetd https://raw.githubusercontent.com/the-lightning-land/sweetd/master/contrib/init.d/sweetd

sudo chmod a+x /etc/init.d/sweetd

sudo update-rc.d sweetd defaults

sudo apt-get install hostapd wireless-tools wpasupplicant dnsmasq iw

sudo systemctl mask hostapd

sudo systemctl mask dnsmasq

sudo service sweetd start

Development

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

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

go build

./sweetd

Releasing using goreleaser

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

Releasing using the release script

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

git push origin v0.1.0

./release.sh v0.1.0

Regenerate grpc files

sweetd exposes a gRPC API. When the API definition in sweetrpc/rpc.proto changes, the following command will regenerate the source files:

protoc -I sweetrpc/ sweetrpc/rpc.proto --go_out=plugins=grpc:sweetrpc

init.d

sudo ln -s $GOPATH/src/github.com/the-lightning-land/sweetd/contrib/init.d/sweetd /etc/init.d/sweetd
sudo update-rc.d sweetd defaults
sudo service sweetd start