Smart Bartender

Why spend lots of money going out for drinks when you can have your own smart personal bartender at your service right in your home?! This bartender is built from a Raspberry Pi 3 and some common DIY electronics.

Prerequisites for the Raspberry Pi

Make sure you can connect a screen and keyboard to your Raspberry Pi. I like to use VNC to connect to the Pi. I created a tutorial about how to set that up on a Mac.

Make sure the following are installed:

• Python 2.7 (should already be installed on most Raspberry Pi)
• pip

Enable SPI

You'll need to enable SPI for the OLED screen to work properly. Typing the following command in the terminal will bring you to a configuration menu.

raspi-config 

Then navigate to Interfacing Options and select SPI. Make sure it's turned on and reboot.

See this article for more help if you need it.

I2C

Make sure i2c is also configured properly. Type

sudo vim /etc/modules

in the terminal

press i, then make sure to paste the following two lines in the file:

i2c-bcm2708
i2c-dev

press esc then ZZ to save and exit.

OLED Setup

The Raspberry Pi Guy has a nice script to setup the OLED screen on your raspberry pi. Download the following repository on your Pi:

https://github.com/the-raspberry-pi-guy/OLED

then navigate to the folder with the terminal

cd ~/path/to/directory

and run the installation script

sh OLEDinstall.sh

There is also a guide on the Adafruit website if you get stuck.

Running the Code

First, make sure to download this repository on your raspberry pi. Once you do, navigate to the downloaded folder in the terminal:

cd ~/path/to/directory

and install the dependencies

sudo pip install -r requirements.txt

You can start the bartender by running

sudo python bartender.py

How it Works

There are two files that support the bartender.py file:

drinks.py

Holds all of the possible drink options. Drinks are filtered by the values in the pump configuration. If you want to add more drinks, add more entries to drinks_list. If you want to add more pump beverage options, add more entries to the drink_options.

drinks_list entries have the following format:

{
		"name": "Gin & Tonic",
		"ingredients": {
			"gin": 50,
			"tonic": 150
		}
	}

name specifies a name that will be displayed on the OLED menu. This name doesn't have to be unique, but it will help the user identify which drink has been selected. ingredients contains a map of beverage options that are available in drink_options. Each key represents a possible drink option. The value is the amount of liquid in mL. Note: you might need a higher value for carbonated beverages since some of the CO2 might come out of solution while pumping the liquid.

drink_options entries have the following format:

{"name": "Gin", "value": "gin"}

The name will be displayed on the pump configuration menu and the value will be assigned to the pump. The pump values will filter out drinks that the user can't make with the current pump configuration.

pump_config.json

The pump configuration persists information about pumps and the liquids that they are assigned to. An pump entry looks like this:

"pump_1": {
		"name": "Pump 1",
		"pin": 17, 
		"value": "gin"
	}

Each pump key needs to be unique. It is comprised of name, pin, and value. name is the display name shown to the user on the pump configuration menu, pin is the GPIO pin attached to the relay for that particular pump, and value is the current selected drink. value doesn't need to be set initially, but it will be changed once you select an option from the configuration menu.

Our bartender only has 6 pumps, but you could easily use more by adding more pump config entries.

A Note on Cleaning

After you use the bartender, you'll want to flush out the pump tubes in order to avoid bacteria growth. There is an easy way to do this in the configuration menu. Hook all the tubes up to a water source, then navigate to configure->clean and press the select button. All pumps will turn on to flush the existing liquid from the tubes. I take the tubes out of the water source halfway through to remove all liquid from the pumps. Note: make sure you have a glass under the funnel to catch the flushed out liquid.

Running at Startup

You can configure the bartender to run at startup by starting the program from the rc.local file. First, make sure to get the path to the repository directory by running

pwd

from the repository folder. Copy this to your clipboard.

Next, type

sudo vim /etc/rc.local

to open the rc.local file. Next, press i to edit. Before the last line, add the following two lines:

cd your/pwd/path/here
sudo python bartender.py &

your/pwd/path/here should be replaced with the path you copied above. sudo python bartender.py & starts the bartender program in the background. Finally, press esc then ZZ to save and exit.

If that doesn't work, you can consult this guide for more options.