How to build the µPi

Collect the hardware

1. Raspberry Pi Zero W . The bare board costs USD$15.00.  If you have the option, by all means get the Raspberry Pi Zero 2 W, which is up to five times faster than the original and costs only a little bit more.  The MicroPi firmware operates with other RP devices as well. See the list below. 

2. You’ll want a case too. 

3. Get a heatsink with the case. 

4. Power Supply ( ~1A @ 5VDC).  This is something that you may already have lying around. Many USB phone/tablet chargers will work, as will a computer with a USB port.  A discarded micro USB phone charger should work, as long as it meets the spec above. Note that an insufficient power supply can cause problems such as SD card corruption. Get a quality, regulated supply.
   Here is a kit having everything listed in 1 - 4. OR, get this one for Raspberry PI Zero 2 W (up to 5 times faster). 

5. MicroSD Flash memory. This must be at least 4GB but can be up to 512GB depending on the size of the materials it is desired to distribute. The software needed to run the device uses about 2.5GB. The remaining space can be filled with materials for distribution. For best results, get at least a speed Class 10 rated card. Quality is important, get a good brand name for best performance. 

6. Micro USB to USB A cable. This can be separate from the power supply cable or can be the same one depending on the style of power adapter. 

7. Computer with Capacity to read SD cards or a USB flash memory reader. Many modern laptops have a card reader built-in. For most of these, a micro SD to SD adapter will be required. This is often supplied with the micro SD card. USB readers are available for use where a built-in reader is lacking.

8. Optional - A “Power Bank” battery recharge device can be used as a power supply to provide autonomy for portable use. 

9. Optional - If you intend to use the Kiosk Mode from a Zero W or Zero 2 W,  you'll need a Mini to Standard HDMI adapter or cable.  Note that the kits listed above include this adapter. Raspberry Pi 4 requires a micro to standard HDMI adapter. See "Kiosk Mode"

Important note: The “Raspberry Pi Zero W” product is an updated version of an earlier device called the “Raspberry Pi Zero”. The earlier device is still for sale (for only $5.00!) but doesn’t include WiFi or Bluetooth. Thus, as kool as a $5.00 computer may be, it is not useful for the MicroPi project. Beware of ads selling Raspberry Pi Zero w Case. (i.e. Raspberry Pi Zero WITH case) which may well order the older Raspberry Pi Zero. There are a lot of kits available offering the Pi Zero W with various combinations of cases, power supplies, cables, interface adapters, SD cards, etc. Just be sure to buy a Raspberry Pi Zero W or it will not be useful for this project.

These Raspberry Pi models have been tested as compatible with the MicroPi firmware. 

• Raspberry Pi Zero W 

• Raspberry Pi Zero 2 W

• Raspberry Pi 3 Model A+

• Raspberry Pi 3 Model B+

• Raspberry Pi 4 Model B 2GB

• Raspberry Pi 4 Model B 4GB

Other models may work as well, but have not been tested by the developers. 

Download necessary Software

Linux users require the package “openssh-client” to allow file installation and "gnome-disk-utility" to create the SD card. Most popular Linux distros install these packages by default.

Windows users will need to download and install three programs which allow Windows computers to write the SD card and communicate with the RaspberryPi. 

• Win32DiskImager or Balena Etcher

• WinSCP or Bitvise SFTP client

• Apple Bonjour Service for Windows* This is also included with iTunes, so if iTunes is already installed on your computer, do not install it. 

*This includes a protocol called "Zeroconf" which  allows computers to find devices on the local network which offer .local URLs.  Recent updates for Windows 10 and Windows 11 include this feature by default.