This document covers Configuring the Solo to your particular needs

NOTE: The default settings of the Solo work well in most situations. If you have built the Solo:basic, they work perfectly. The easiest thing to do is to change nothing in the configuration. Just flash the memory card, plug it into the Solo, and turn on the Solo.

How to configure

Once a memory card is flashed with the SOSI (solo operating system image), it can be re-inserted into your PC/laptop, and your computer will mount a /boot partition onto your desktop. Look in this folder and you’ll find a directory called “solo”, and in there, two files - solo.conf and amon.conf. Their full path is boot/solo/solo.conf and boot/solo/amon.conf. These are the configuration files for solo, and you will edit them by hand on your PC, save them, close your editor, and then carefully eject the “boot” partition.

Note: On windows you will see ONLY the boot partition, on mac and (certainly) on linux you will see an additinal parition - which should be ignored.

solo.conf and amon.conf

There are 2 configuration files, because one deals with “device” settings (solo.conf) and the other with “audio” settings (amon.conf). amon is the “audio monitor”, it’s the software that runs on the Solo and manages the audio recordings.

Config options in amon.conf

  • CHANNELS=”-c1” controls stereo or mono. Set it to 1 or 2

  • SAMPLERATE=”-r16000” controls the sample rate of the audio in Hz. Set it to 8000, 16000, 44100 or anything up to 192000, depending on your audio-card’s capability.

  • CLAC_VOL is a volume control. range is [0,31] representing [0dB->31db] in 1dB steps. Max out this volume before raising the CLAC_DIGITAL_VOL. The default is the maximum of 31, representing a gain of 31dB.

  • CLAC_DIGITAL_VOL is a digital volume. Range is[0,191] representing [-64dB->+32dB] in 0.5dB steps (so 128 is 0dB) The default is CLAC_VOL=152 representing +12dB.

  • CLAC_AUDIO_SOURCE Selects the jack to record from. “linein” selects the pink “line-in” socket which I recommend. This socket provides PIP (plug in power) to drive your mic with a few volts if it needs it. “dmic” selects the onboard stereo Digital MEMS microphones. mic selects the black “headphone” socket which is intended for headphone/microphone headsets. I haven’t used this, but I think it requires a connector with 4 sections (Left headphone, Right headphone, Microphone and Ground). I think. The default is “linein”

  • DURATION=10 controls the duration of the recorded audio files (how often they are split) in minutes. Anything up to 60 mins is supported at the moment. DURATION=10 is the default 10 minutes. Actually the behaviour is : every minute we consider splitting the audio. If (minute-hand-of-current-time-of-day / DURATION) leaves a zero remainder, then we DO split. It’s written this way so that the Solo immediately synchronises the splits with wall-clock time. But it isn’t perfect.

  • CALENDAR=filename see the dedicated page on using the calendar. This string must be the full path to a valid calendar file.

  • undocumented options The following are undocumented, stale, unused, unreliable, so ignore them unless you know what you are doing: AMONDATA, MINMEMFREE, AUDIODEVICE, AUDIOFORMAT, ABUFFER. NIGHTLYREBOOT, CLAC_PIP

Config options in solo.conf

Setting the Timezone (SOLO_TZ)

The timezone of the Solo is set through the /boot/solo/solo.conf file. The entry is SOLO_TZ. It defaults to Etc/GMT.

SOLO_TZ=Europe/London and SOLO_TZ=America/Panama would be a valid example. As would UTC for Universal coordinated time (Zulu). Acceptable timezones are listed here.

If you choose a timezone which uses daylight saving, then be aware that there will be one hour of the year (in spring), when an hour’s worth of recordings are overwritten, and in Autumn, there will be an hour’s gap in recordings. To avoid this, use a timezone that DOESNT use daylight savings. These include timezones like Etc/GMT, Etc/GMT-5 (for Boston, USA), Etc/GMT+3 for Athens.

If you are using Calendars, take particular care to select a timezone that doesn’t use Daylight Savings, as it will cause confusing problems with reboot times.

Setting the Power mode (SOLO_POWERMODE)

The powermode controls how much power saving is done by the software on the Solo. The only two settings currently are

  • lowest: This is the default - it uses the least power (including turning off the HDMI connector, so a monitor connected to that socket will NOT work.)

  • normal: This performs no special measures to minimize power (including leaving the HDMI/monitor socket operational).