Not much free time these days so updates have been slow.. but I have a lot of interesting stuff cooking in the back burner.
One of them is an audio grade RPi.
Essentially it will be a Compute Module 3 on a mainboard loaded with ultra low noise linear power supplies and some necessary peripherals.
The idea came to me quite some time ago but it wasn’t until last November that I decided to actually go ahead with it.
The proof-of-concept PCBs for the mainboard were done by December.
It appears that even the PoC board, with average quality power supplies, has a cleaner I2S output compared to a standard RPi3 powered by an equivalent linear power supply:
Audio grade Pi:
The next part was the PoC board for the USB Hub & Ethernet controller. That took a bit more time and a 4-layer PCB with numerous 0402 sized components but it too ended up just fine (with the exception of a bad RJ45 footprint..).
So now I have a fully functioning set of boards with average quality power supplies that already performs better than my Squeezebox Touch as a USB transport.
Next step is to design a single board integrating all of the components plus ultra high quality power supplies.
They are single board computers (SBCs) much like the Raspberry Pi, but they will set you back just over 10€ plus shipping. That is just insane value.
They offer a quad core ARM Cortex A7 processor running at 1.2GHz, 512MBs of DDR3 RAM, an Ethernet port (One) or WiFi (Lite), a couple of USB ports, an HDMI port, etc.
They run Linux (of course..) or Android.
I needed an inexpensive way to listen to internet radio while I was in my kitchen. I already had a low end system set up, consisting of a couple of bookshelf speakers, a power amp and a Squeezebox Classic, but I had to move the Squeezebox to another room so I needed something to take its place. The Orange Pi One plus an inexpensive I2S DAC would fit the bill very nicely.
The idea was to load a stable Linux distribution onto the One and set-up MPD to work with my el-cheapo I2S DAC.
The steps that I am about to describe took me about a day to figure out and needless to say, I learned a lot in the process.
Let’s start with the basics.
You will need an Orange Pi board, a proper power supply (USB power will not work – I suggest that you buy a bundle of Orange Pi + Power Supply from aliexpress), a 4GB (or bigger) Micro SD card and an I2S compatible DAC that does not require a MCLK signal (like an ES9023-based one with an on-board oscillator). For the initial setup you will also need a monitor with an HDMI (or DVI with an adapter) input plus a USB keyboard. If you are a bit more hardcore, instead of using a monitor & keyboard, you can just use the Pi’s serial port with a serial to USB module and putty.
The first step is getting our hands on a Linux distribution that will be a good fit to our application. You might notice that there exist a number of official One distributions: http://www.orangepi.org/downloadresources/ The Lite is not so lucky.
The general consensus is that most of them have issues. The best choice appears to be the Armbian distribution:
Armbian is based on Debian and is very similar to Raspbian (also based on Debian), so if you’ve used Raspbian on a Raspberry Pi you will feel right at home.
For our application we are going to go with the Jessie Server image. We need to put this image file on a Micro SD card. I use Rufus.
We insert the SD card in the Orange Pi, we connect our monitor, keyboard, ethernet and power the thing up.
After about 15-20 seconds, the green power-on LED will start flashing and soon after you will see the initial login screen:
The default credentials are root/1234.
You need to change the default password to one of your liking. Following that, your Pi will request that you create a new user account:
Once you’ve done that, you will be asked whether you would like to change your Pi’s resolution to match your screen’s:
In my case, my lab’s monitor has a 1920×1200 resolution, so I chose to go with the highest supported resolution, so I typed:
h3disp -m 10
One reboot to go and we will be done with the initial setup.
At this point I should point out that I routinely log in to my Orange Pis as root. I can see some of you cringing but I don’t care. Security is way low on my list of concerns when it comes to my SBCs that I use for music playback. If you use a normal user (and not root) on your SBC, all you have to do is prefix the commands that I use with the command “sudo”.
So now, if you have a Pi One and it is connected to your network, it should have acquired an IP from your DHCP server. If you have a Pi Lite, you will need to do some extra work to get it to connect to your WiFi network.
To configure the Lite’s WiFi adapter you need to edit the interfaces file:
If you would like your Pi to get an IP automatically from a DHCP server, you do this:
Again, replace your_ssid and your_password with your actual SSID and password. Note that it doesn’t matter if you are using WPA or WPA2, the script is the same.
When you are done, save the file (Ctrl-X and then Yes a couple of times) and reboot your Lite.
When the system comes back up log in and check if you are connected to your access point by typing:
You should see something like this:
1: lo: mtu 16436 qdisc noqueue state UNKNOWN group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: tunl0: mtu 1480 qdisc noop state DOWN group default
link/ipip 0.0.0.0 brd 0.0.0.0
3: wlan0: mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:e0:4c:99:f8:3b brd ff:ff:ff:ff:ff:ff
inet 192.168.0.200/24 brd 192.168.0.255 scope global wlan0
inet6 fe80::2e0:4cff:fe99:f83b/64 scope link
valid_lft forever preferred_lft forever
You should see that your wlan0 interface now has an IP.
Congrats, your Lite now has network access. This means that you can put away the monitor & keyboard that you used to configure your Lite and continue on your desktop / laptop by logging in through SSH (using Putty or any other SSH compatible terminal program).
Logging in from Putty, we come to this prompt:
Next, we have to do a full update & upgrade of our installed packages:
The update part should go pretty fast, but the upgrade part will take some time, depending largely on your SD card’s performance.
This concludes Part 1 (a.k.a. “the boring part”). Part 2 will include enabling the Orange Pi’s I2S output and setting up MPD.