IoT pHAT review

By Russell Barnes. Posted

An easy way to add WiFi and Bluetooth to your Pi Zero

One of the best new features of the Raspberry Pi 3 is its built-in wireless LAN and Bluetooth. Wouldn’t it be great to have the same convenience on a Pi Zero (and other Pi models)? That’s the thinking behind Red Bear’s IoT pHAT. When mounted on the GPIO pins, this Zero-size board provides WiFi (802.11bgn / 2.4GHz) and Bluetooth (4.1 and BLE) connectivity. So you don’t need to use a dongle plugged into the Pi Zero’s solitary data micro-USB port via a USB OTG adapter.

The full article can be found in The MagPi 50 and was written by Phil King.

The IoT pHAT is pretty much plug-and-play, coming pre-soldered with a 40-pin female header. Upon booting up, the Linux kernel reads the configuration from the on-board EEPROM and turns on the WiFi driver. You can then connect to your wireless router as usual, via the desktop panel icon or command line.

While on our early model we needed to update the pHAT’s firmware via several terminal commands to get more stable WiFi and functional Bluetooth, any new boards shipped should already have this pre-installed and so work perfectly from the start. One caveat is that, at the time of writing, you’ll still need to add a line to the /boot/config.txt file to set the UART clock to 48MHz to activate Bluetooth, but this is due to be added to the next official Raspbian image. Once Bluetooth is working, you can pair devices – such as a keyboard, mouse, and gamepad – via the desktop panel icon or command line, as usual.

In our tests, the IoT pHAT provided reliable and fast connections for both WiFi and Bluetooth, which is hardly surprising since it uses the same Broadcom 43438 wireless radio chip used in the Pi 3. The signal strength and quality from the on-board antenna were fine, but can be improved by adding an optional external antenna kit ($9/£7) if needed. As the pHAT only uses 15 GPIO pins and leaves 11 free, including the I2C and SPI pins (see the handy guide for details), it’s possible to stack it on top of most other add-on boards, such as the Enviro pHAT or Analog Zero, equipped with an extra-long stacking header.

Last word


The IoT pHAT is a neat and convenient way to add WiFi and Bluetooth connectivity to your Pi Zero, while freeing up the data port. Using the same wireless radio chip as the Pi 3 results in reliable signal strength and quality via an on-board or optional external antenna.