Hardware information for Raspberry Pi setups¶
(Note: If you’re defaulting to Raspberry Pi because that’s what you’ve seen pictures or heard stories of - you should also check out the Edison-based rig page for details on a smaller, more mobile friendly option. A Pi/TI stick rig is a good “at home” rig, but most people want the smallest, which is an Edision/Explorer Board rig (pictured here) that they can slip in their pocket. The next page has the Edison required hardware.)
The Raspberry Pi (RPi) is a credit-card sized single-board computer. The RPi primarily uses Linux kernel based operating systems, which must be installed by the user onto a micro SD card for the RPi to work. The RPi currently only supports Ubuntu, Raspbian, OpenELEC, and RISC OS. We recommend installing either Ubuntu or Raspbian. Later in the docs under recommended setup, you will learn how to do a “cableless” and “headless” install of Raspbian. You will be able to access and control the RPi via an SSH client on Windows, Mac OS X, Linux, iOS, or Android.
The RPi has 4 USB ports, an Ethernet port, an HDMI port, and a micro USB power-in jack that accepts 2.1 Amp power supplies. In this tutorial, you will need to access the USB ports, micro USB power-in jack, and possibly the Ethernet jack (if wireless failure occurs).
High level list of supplies needed for a Pi-based setup:
- One of the following:
- Raspberry Pi 2 Model B (“RPi2”) with a Low-profile USB WiFi adapter (see “Raspberry Pi 2” section below)
- Raspberry Pi 3 Model B (“RPi3”) with built in WiFi
- A Carelink USB or alternative radio stick
- An 8 GB (or greater) micro SD card
- Additional Supplies
- Micro SD card to regular SD card converter [optional, but recommended so that you can use the micro SD card in a regular sized SD card drive]
- 2.1 Amp (or greater) USB power supply or battery
- Micro USB cable(s)
- Case [optional]
- Cat5 or Cat6 Ethernet cable [optional]
- HDMI cable [optional, used for connecting the RPi2 to a screen for initial setup ease]
- USB Keyboard [optional, used to interact with the RPi2 via its own graphics interface on your TV screen]
- USB Mouse [optional, for the same purpose]
Raspberry Pi 2¶
The Raspberry Pi 2 has fewer and lower spec components and so draws less power, but requires a WiFi adapter to be also purchased. The spec makes no difference to the OpenAPS app, so either model is suitable choice.
Raspberry Pi 3 Model B¶
The Raspberry Pi 3 has higher specs and built-in WiFi and Bluetooth, so it draws more power. As a consequence, it has a shorter battery life than the Raspberry Pi 2. So when selecting portable battery packs bear this in mind.
Micro SD Card¶
An 8 or 16 GB micro SDHC card is recommended. Get one that is class-4 or greater and is a recognized name brand, such as SanDisk, Kingston, or Sony. A list of verified working hardware (including SD cards) can be found here.
Note: A known issue with the Raspberry Pi is that the SD card may get corrupted with frequent power cycles, such as when the system gets plugged and unplugged frequently from an external battery. Most core developers of openaps recommend purchasing extra SD cards and having them pre-imaged and ready to use with a backup copy of openaps installed, so you can swap it out on the go for continued use of the system.
WiFi Adapter (Raspberry Pi 2 only)¶
A minimalistic, unobtrusive WiFi USB adapter is recommended. The low-profile helps to avoid damage to both the RPi2 and the adapter as the RPi2 will be transported everywhere with the user.
2.1 Amp USB Battery Power Supply¶
A large-capacity power supply that is greater than 8000 mAh (milliAmp-hours) is recommended for full day use. Make sure that the battery has at least one 2.1 Amp USB output. A battery with a form-factor that minimizes size is recommended, to allow the patient to be as ambulatory as possible. When you have a full OpenAPS implemented and working, you will want to have multiple batteries to rotate and recharge. A battery that can deliver power while it charges is ideal as you will be able to charge it on-the-fly without shutting down and restarting the Raspberry Pi.
USB cables with a micro connector on one end and a standard (Type A) connector on the other are used to connect the power supply and the Dexcom receiver to the Raspberry Pi. Most cables will work fine, but some prefer to select lengths and/or features (such as right-angled connectors) to improve portability.
The Raspberry Pi is extremely minimalistic and does not come in a protective case. This is fine for development work, but presents an issue for day-to-day use. There are hundreds of cases available, but here is an example of what others are using in their OpenAPS builds:
Additionally, for mobile use, it is helpful to have something besides a lunchbox to carry the entire rig around. The size and weight of the component set as well as the limited range of the CareLink USB stick constrains the options here, but there are still some workable solutions. Waist-worn running gear and camera cases seem to work well. Two options: FlipBelt and Lowepro Dashpoint 20.
HDMI Cable, USB Keyboard, USB Mouse¶
For the initial set up of the Raspberry Pi you may want to use a monitor and keyboard/mouse to set up the WiFi connection, but all other access can be done through a SSH Terminal (explained later). This means the monitor, mouse, and keyboard are only used for a few minutes and generally aren’t required again.