====== Raspberry Pi NAS: The X835 board ======

This page is about using the **SupTronics X835** with the Raspberry Pi, to be used as NAS and mediacenter. See the main index at **[[raspberrypi_nas]]**.

In January 2021 I purchased an HDD shield for the Raspberry Pi, it is the **[[http://www.suptronics.com/miniPCkits/x835.html|X835]]** model produced by **[[http://suptronics.com|suptronics.com]]**. It is not so cheap: I had to pay about **32 Euros** on Aliexpress for the bare board, without a power supply. The board can accomodate a **3.5 inches hard disk**. I wish to build an **home NAS** with integrated **multimedia center functions** based on **[[https://kodi.tv/|Kodi]]**. The output will go to an HDMI attached 32 inches display.

{{.:raspberrypi:x835_suptronics.jpg?400|}}

===== Hard disk screws thread problem =====

{{ .:raspberrypi:x835-hd-screws-problem.jpg?200|X835 HD Screws}}
The **screws** used to mount **3.5 inches hard disks** are of the **[[wp>Computer_case_screws|#6-32 UNC]]** type (3.51 mm diameter, 0.79 mm thread pitch). Quite surprisingly the X835 board has four **M3 threaded holes** and provides four M3 screws (3.00 mm diameter, 0.50 mm thread pitch). It is a **bad design** to **pair two threaded holes** (the board and the hard disk), but it is really a madness to use **screws in holes with different diameter and thread**!

So my advice is to **enlarge the holes in the board**, so that you can pass **#6-32 screws** to properly attach the hard disk.

===== 2.4 GHz WiFi and USB 3.0 interference problem =====

{{.:raspberrypi:wifi-forbidden.png?90 |WiFi Warning}}
Long story short: the **USB 3.0** signals cause **interferences** on the **2.4 GHz** frequencies, so you can experience grave problems on **WiFi** connectivity or **keyboard/mouse wireless** dongles. People say that there are not problem on 5 GHz WiFi.

Unfortunately I must confirm that the **2.4 GHz WiFi problem is severe**: I cannot connect to the **access point** which is just **some meters away** in the same room. Also my **wireless keyboard** (which uses an USB dongle operating on the 2.4 GHz band) become **unresponsive** when I walk away from the Raspberry Pi by just **one or two meters**.

I tried to **shield** the X835 board from the Raspberry Pi using an **aluminium foil** grounded to the negative pole of the power, but it was useless. It seems that the interference is generated **into the Raspberry Pi circuits itself**, it is not  added by the X835 board. Infact you can read on the internet several story about Raspberry Pi, USB 3 and 2.4 GHz WiFi problems, which do not involve the SupTronics interface.

So the only viable solution for **network connection** is to use a **5 GHz WiFi** access point or the **Ethernet** cable. If you need a **wireless keyboard** or **gamepad** you can connect the USB dongle to the Raspberry Pi using an extension cable; I use one about of 0.5 meters, taking care to arrange the cable as far as possible from the Raspberry Pi. In this way **I can operate the gamepad** in the room at a distance of about 5 meters.

If you **connect the X835 board** through one **USB 2 interface** of the Raspberry Pi, you can solve the interference problem. I tried that configuration and I was able to use a **remote keyboard** and a **remote gamepad** (both using a 2.4 GHz USB nano dongle) with no problems. You have to forgo the hard disk performance granted by the USB 3.0 bus (e.g. 185 Mb/s read rate) and stuck to USB 2 (32 Mb/s).

  * **[[https://hackaday.com/2019/11/28/raspberry-pi-4-hdmi-is-jamming-its-own-wifi/|Raspberry Pi 4 HDMI Is Jamming Its Own WiFi]]**
  * **[[https://www.indilib.org/forum/general/6576-pi4-usb3-and-wireless-2-4ghz-interference.html| Pi4, USB3, and Wireless 2.4Ghz interference]]**
  * **[[https://www.raspberrypi.org/forums/viewtopic.php?t=254374|RPi4B Problem Using USB 3.0 HDD (PSU problem?)]]**
  * **[[https://github.com/raspberrypi/firmware/issues/1430|USB3 and 2.4 GHz Wifi]]**

===== Web References =====

  * **{{.:raspberrypi:suptronics-x835-board-raspberry-pi4.pdf|SupTronics X835 User Manual}}**