The Raspberry Pi 400 in combination with the Waveshare Raspberry Pi 400 GPIO Header Adapter form a perfect team when it comes to using the full potential of the user-accessible I/O pins. If you are using pre-made HATs (or even if you are creating your first breadboard experiments), this team will simplify things for you. It gives you visible, easy-to-identify pins that you can reach without having to turn the Raspberry Pi 400.

The Raspberry Pi 400

The Raspberry Pi 400 is a Raspberry Pi in the design and spirit of a classic home computer like the Atari 800, the C64, or the Amstrad CPC, which shaped the image of home computers in the 1980s. If you want to take a look at the history of home computers, check out the free PDF "The Computers That Made Britain".
 
Raspberry Pi 400
Raspberry Pi 400

This is a small desktop computer based on the hardware of the Raspberry Pi 4B. With its Debian Linux-based Raspberry Pi OS, this computer provides a full desktop with which you can surf the web, watch videos or use text and spreadsheet calculation. Something that distinguishes the Raspberry Pi 400 from a normal desktop PC is not only its shape, but also the Raspberry Pi's usual 40 pin header on the back. In combination with the book The Official Raspberry Pi Beginner's Guide (4th Edition), the Raspberry Pi 400 becomes not only a desktop PC but also a platform to start programming. A review of the Raspberry Pi 400 by Clemens Valens can be found on the Magazine page of Elektor and a video on Elektor TV Channel  on Youtube.

 

Waveshare Raspberry Pi 400 GPIO Header Adapter

Something that quickly stands out on the Raspberry Pi 400 is the position of the GPIO header. Since it is attached to the back, it is not easy to find the appropriate pins for the experiments. Each time you have to search at the back.
HAT connected to Raspberry Pi 400 without Adapter

Here the Waveshare Raspberry Pi 400 GPIO Header Adapter provides a cheap and easy option to get comfortably to the pins of the Raspberry Pi 400.
 
Waveshare Raspberry Pi 400 GPIO Adapter
Waveshare Raspberry Pi 400 GPIO Adapter
Raspberry Pi 400 HAT wiht Adapter
With Adapter HATs are usable again

All the pins are labeled on the adapter, and the pins are double housed. So, HATs for the Raspberry Pi can be used without facing away from the user which is especially useful for HATs that have sensors, buttons or display elements on the top. The access to the pins for your own experiments with plugged HATs remains, because not every HAT leads the pins out again.  

If you would like to start with your Raspberry Pi 400 today, have a look at the Elektor Store and grab the Raspberry Pi 400 + Waveshare Raspberry Pi 400 GPIO Header Adapter bundle. 
 

Hint: If the Mouse Is a Little Bit Behind


Here's a note about something that is especially noticeable with the Raspberry Pi 400. With some USB mice, the mouse pointer lags behind the movement of the mouse for what feels like seconds. If you have such a USB mouse, a single entry in cmdline.txt can help. Open a terminal and execute sudo nano /boot/cmdline.txt. Add usbhid.mousepoll=0 at the end of the line and save the file. After a reboot, the mouse cursor should now directly follow your mouse movements.