Power options for RPi + Allo BOSS v1.2

[CallMeMike]

Hi William,

I run my Piano 2.1 config with 2 x 5V feeds from an Anker battery similar to #5. The power sequence I use is below.

Powering down

Perform Menu, Restart, Shutdown and wait for the green activityr LED on the Pi to blink 10 times indicating the shutdown sequence is complete and power can safely be disconnected.

1. Disconnect power from the Pi
2. Disconnect power from the DAC

Powering up

1. Connect power to the DAC
2. Connect power to the Pi

Hello Tim

I want to develop a shunt regulated power supply (at least for my Allo Boss dac), and I would like to automate the power up (and down).
How much time does it take to turn on the raspberry after the dac ?

(... probably your question went unnoticed...)

I assume you need to find out how long it takes for the RPi to be fully functional while running Moode after Power ON. This would depend on several factors:
- the model of RPi
- the Moode version
- the booting device the Moode Player is installed upon (quality and speed of the uSD card / USB memory stick / classic or SSD HDD)
- the charasteristics of the RPi power supply

Probably is best if you time yourself the RPi as a 'standalone' player (SSH...?... I guess HDMI goes 'off' at some point but you can try...). Please let us know your findings (and characteristics of your RPi kit) if you succumb to run such tests

[Tim Curtis]

Boot time can be determined by

1. mark the power on or reboot start time using a watch/clock
2. view moode log and record the time of the line below

20181027 092852 worker: Ready

The difference between the two times is the actual time it takes for moOde to boot up and become ready for client connections. It should be accurate within a few secs.

The amount of time it takes to boot up and become ready depends on many factors including how quickly an IP address is assigned by DHCP, the number of renderers that are started, how long it takes to mount any NAS devices that are configured, the speed of the boot media (SDCard or USB drive), the speed of the network, the speed of the Pi CPU etc.

-Tim

[yannig]

(... probably your question went unnoticed...)

I assume you need to find out how long it takes for the RPi to be fully functional while running Moode after Power ON. This would depend on several factors:
- the model of RPi
- the Moode version
- the booting device the Moode Player is installed upon (quality and speed of the uSD card / USB memory stick / classic or SSD HDD)
- the charasteristics of the RPi power supply

Probably is best if you time yourself the RPi as a 'standalone' player (SSH...?... I guess HDMI goes 'off' at some point but you can try...). Please let us know your findings (and characteristics of your RPi kit) if you succumb to run such tests

RPi 3B or 3B+
moode last version
standard class10 sdcard
Allo Boss.


I guess I do not care much about the booting time of moode+ Rpi.

I just need to know how much time I have to wait after the dac powering to power the rpi

and (perhaps) how much time I have to wait after the powering down of the Rpi to power down the dac.

I just want to automatize the powering up (and down) of these 2 supplies, without associating the software.

[CallMeMike]

(... probably your question went unnoticed...)

I assume you need to find out how long it takes for the RPi to be fully functional while running Moode after Power ON. This would depend on several factors:
- the model of RPi
- the Moode version
- the booting device the Moode Player is installed upon (quality and speed of the uSD card / USB memory stick / classic or SSD HDD)
- the charasteristics of the RPi power supply

Probably is best if you time yourself the RPi as a 'standalone' player (SSH...?... I guess HDMI goes 'off' at some point but you can try...). Please let us know your findings (and characteristics of your RPi kit) if you succumb to run such tests

RPi 3B or 3B+
moode last version
standard class10 sdcard
Allo Boss.


I guess I do not care much about the booting time of moode+ Rpi.

I just need to know how much time I have to wait after the dac powering to power the rpi

and (perhaps) how much time I have to wait after the powering down of the Rpi to power down the dac.

I just want to automatize the powering up (and down) of these 2 supplies, without associating the software.

I understand very well your plan. When I started to use two PSUs in connection to a RPi and a HAT DAC I've briefly entertained the wish to set-up an automatic POWER UP/DOWN of the kit but then i became complacent helped by the fact that the RPi/DAC combo is left permanently ON unless I test a new PSU or Tim & Team 'disturb' the peace of my RPi with a new Moode version . I always use a quality uSD card and my house is not plagued by frequent power outages...

My empirical rule-of-thumb manual ritual:
- RPi power up 30 seconds after the HAT DAC power up
- HAT DAC power down 30 seconds after RPi power down

[willyside]

(... probably your question went unnoticed...)

I assume you need to find out how long it takes for the RPi to be fully functional while running Moode after Power ON. This would depend on several factors:
- the model of RPi
- the Moode version
- the booting device the Moode Player is installed upon (quality and speed of the uSD card / USB memory stick / classic or SSD HDD)
- the charasteristics of the RPi power supply

Probably is best if you time yourself the RPi as a 'standalone' player (SSH...?... I guess HDMI goes 'off' at some point but you can try...). Please let us know your findings (and characteristics of your RPi kit) if you succumb to run such tests

RPi 3B or 3B+
moode last version
standard class10 sdcard
Allo Boss.


I guess I do not care much about the booting time of moode+ Rpi.

I just need to know how much time I have to wait after the dac powering to power the rpi

and (perhaps) how much time I have to wait after the powering down of the Rpi to power down the dac.

I just want to automatize the powering up (and down) of these 2 supplies, without associating the software.

I understand very well your plan. When I started to use two PSUs in connection to a RPi and a HAT DAC I've briefly entertained the wish to set-up an automatic POWER UP/DOWN of the kit but then i became complacent helped by the fact that the RPi/DAC combo is left permanently ON unless I test a new PSU or Tim & Team 'disturb' the peace of my RPi with a new Moode version . I always use a quality uSD card and my house is not plagued by frequent power outages...

My empirical rule-of-thumb manual ritual:
- RPi power up 30 seconds after the HAT DAC power up
- HAT DAC power down 30 seconds after RPi power down

@CallMeMike,

I'm curious how you came to decide something on the order of 30 seconds was necessary? I seldom wait more than 2 seconds between powering up my Allo Boss and powering up my RPi (and the same amount of time for powering down, in the reverse order), and I assumed even that was more than necessary. Did you have a negative experience waiting less than around 30 seconds? 

Regards,
William

[CallMeMike]

(... probably your question went unnoticed...)

I assume you need to find out how long it takes for the RPi to be fully functional while running Moode after Power ON. This would depend on several factors:
- the model of RPi
- the Moode version
- the booting device the Moode Player is installed upon (quality and speed of the uSD card / USB memory stick / classic or SSD HDD)
- the charasteristics of the RPi power supply

Probably is best if you time yourself the RPi as a 'standalone' player (SSH...?... I guess HDMI goes 'off' at some point but you can try...). Please let us know your findings (and characteristics of your RPi kit) if you succumb to run such tests

RPi 3B or 3B+
moode last version
standard class10 sdcard
Allo Boss.


I guess I do not care much about the booting time of moode+ Rpi.

I just need to know how much time I have to wait after the dac powering to power the rpi

and (perhaps) how much time I have to wait after the powering down of the Rpi to power down the dac.

I just want to automatize the powering up (and down) of these 2 supplies, without associating the software.

I understand very well your plan. When I started to use two PSUs in connection to a RPi and a HAT DAC I've briefly entertained the wish to set-up an automatic POWER UP/DOWN of the kit but then i became complacent helped by the fact that the RPi/DAC combo is left permanently ON unless I test a new PSU or Tim & Team 'disturb' the peace of my RPi with a new Moode version . I always use a quality uSD card and my house is not plagued by frequent power outages...

My empirical rule-of-thumb manual ritual:
- RPi power up 30 seconds after the HAT DAC power up
- HAT DAC power down 30 seconds after RPi power down

@CallMeMike,

I'm curious how you came to decide something on the order of 30 seconds was necessary? I seldom wait more than 2 seconds between powering up my Allo Boss and powering up my RPi (and the same amount of time for powering down, in the reverse order), and I assumed even that was more than necessary. Did you have a negative experience waiting less than around 30 seconds? 

Regards,
William

As I said... empirical rule-of-thumb  
As the POWER OFF/ON ritual is happening so infrequent I have not given much thought about a precise timing, let alone testing... I've considered half a minute beeing suffient enough for everything to settle down (and I do not use the watch while I wait patiently so no precision there as well)

[yannig]

thanks for your replies, guys

I think I'll go for wait times of 2 seconds...

[DavidPlatt]

There's another power architecture I'd like to suggest - multiple regulation.  Basically:

(1) Start out with a DC supply of somewhere around 12 volts, capable of delivering as much amperage as your system will need (probably 2-3 amps).
(2) Use two or more separate linear regulators to down-regulate this 12 volts, to the 5 volts needed by the various modules.
(3) Pay attention to how you do the power grounding.

I built a player like this earlier this year, using a Pi 2, a HAT-sized prototyping card, and a generic I2S DAC card with a PCM510x DAC chip.  The high-voltage supply is a 12-volt 3-amp switching-type "power brick" which plugs into the back of the player case.  The DC wiring goes to a 7805-type TO-220 regulator (a mil-spec variant I had handy) that's bolted to the bottom of the case - this provides 5 volts to the Pi, via the HAT card and the power/ground pins on the header.  The 12 volts also runs over to the corner of the HAT card, where I have a 78L05 regulator (a little TO-92 part) which then supplies the DAC module soldered to the HAT prototyping area.

Both of the 5-volt regulators have bypass caps on their inputs and outputs, to provide local decoupling and ensure stable operation.

I think this approach has a lot of advantages.  The use of two separate regulators helps isolate the DAC from any power-supply "surge" noise introduced by the Pi (and the DAC module has its own low-dropout regulator which increases the isolation still further).

i was a bit concerned about whether a single 7805-type regulator could handle the current demands of a Pi 2, considering that it's dropping 6-7 volts across the regulator and could (worst case) dissipate quite a few watts of heat.  So far it's had no problem... neither the case nor the regulator has gotten more than barely warm to the touch, and I haven't had any unstable operation or crashes.  Considering that the Pi cores are about 95% idle during playback of my Ogg Vorbis collection, the low power usage makes good sense.  One could always use a heftier 5-volt regulator, or parallel two of them, or use a hybrid regulator (a 7805 with an outboard pass transistor to do the heavy lifting) if one wanted.

There's a way to gild the lily here that I haven't tried... pre-filtering the 12-volt input to the 5-volt regulators even further, using a capacitance multiplier.  With a single transistor (or Darlington), a modest-sized cap, and a couple of resistors, one can create an extremely "stiff" voltage buffer which would greatly attenuate any switching noise from the 12-volt "brick" before it got to the 5-volt regulators.

A similar approach ought to work out well for any Pi setup using a DAC that has independent provisions for power input.

[DRONE7]

Yes, you have satisfied one of the main requisites for stable Pi powering.... keep the path from the power supply/regulation to the Pi as short as possible.

Like you I use a 12v 3 amp smps wall-wart then to a dc-dc converter with regulation that is as close to 'onboard' the Pi as possible.

Everything else, though measuring correctly for stable 5v, caused the onboard red power led to flash occasionally.

USB cables can be notoriously poor in their capacity to supply the demands of the Pi.
Just google the V/A standards for usb cables then realise that those are 'ideals' that most manufacturers do not meet...

[mrdrew]

@willyside what did you end up going with? Did you try a test to see if you could tell the difference between different power configurations?