Re: WAV file audio

Nosey Nick VA3NNW

David Cameron - IRLP wrote:
With the advent of Pi-based systems, there is not a real reason not to
upgrade to something newer. I imagine with the cost of electricity,
you will recoup your up front cost in a matter of a year or two.
I thought this would be fun to calculate, kinda back-of-envelope but
with citations...

Raspi power consumption depends slightly on what model you're using and
how hard you're working it, but it's never eating TOO much CPU, IRLP is
mostly idle with occasional laid-back I/O. says it supports "Raspberry Pi (models B and
B+), Pi2, and now [...] Pi3", but the ordering page has a Pi4 one, and I
happen to know it also works fine on a Pi Zero, but
and tend to
agree fairly well:

Power used:
Best case about 1.5W  (except honestly, only 0.75W for the pi zero?
Wow!  :-O )
Worst case about 3W

Compared with (say)

1st-gen Pentium 15W
Pentium 3 more like 27W
Pentium 4 more like 60-75W
Some are much MUCH worse, but I doubt anyone is running IRLP on a
dedicated 4-socket 8-core 3GHz server or anything.

However the above is ONLY THE CPU not the rest of the PC, so
Low-end Motherboard 25 to 40W
RAM 2-5W
Assume you have no GFX card
HDD, old "spinning rust" one: 1-9W
Fans 1-6W ea
50-80% efficient PSU...

Tell you watt ('scuse the pun) let's just go with
Best case 117W, maybe you also already optimised by removing the GFX and
CD/DVD drive to bring down to 90W
Worst-case let's borrow their mid-range 278W

So the DIFFERENCE between your complete rpi system vs your old PC:
Best-case 278W-1.5W = approx 275W saving
Worst-case 90W-2.5W = 87.5W saving

Hours in a year: 8760 to 8784 for leap years
So best-case saving 275W * 8784hrs = 2415.6kWhr
worst-case only 87.5W * 8760hrs = 766.5kWhr saved

Home energy cost from
Best case about 8c / kwH
Worst case about 22.2c / kwH

So best-case saving 2415.6kWhr @ 22.2c = $536/yr
Worst-case saving "only" 766.5kWhr @ 8c = $61.32/yr
Note that these are nearly an order of magnitude, depending on what
you're replacing, what with, ans where you live!

RRP of a Pi from or

Pi Zero $4 but realistically you want the Pi Zero W $13 or with
pre-soldered header $17
Pi Zero W + sdcard + PSU + case + HDMI adapter $30
Pi 3 bare $20
Pi 4 + sdcard + PSU + case + HDMI cable $63
All the above assume you already have an IRLP board and are happy to
make the very simple 3.3V mod and follow the instructions to install
raspbian and the PIRLP software. Add $5-$10 for a USB sound card.
Up to $350 for the fully assembled
ready-to-go pirlp node with brand new board, all OS+software etc

Let's say best-case is you're buying the pi zero + case + PSU + sdcard +
$5 USB sound-card and doing ALL the work yourself, including modding an
existing irlp board, to replace the hungriest PC above, somewhere with
expensive electricity. $35 spent to save $536/yr - pays for itself in
approximately 24 days.

Worst-case, paying for the fully-built $350 pirlp to replace a low-end
further-optimised 90W PC somewhere with cheap 8c electricity... $350 to
save $61.32/yr, about 5.7yrs to pay for itself.

Realistically, you're somewhere in the middle of each, say, 165W saved,
somewhere that charges 17c/kWhr, saving about $240/yr
... Which would pay for a $63 "DIY pi 4" pirlp upgrade in just over 3
months, or a full brand new $350 plug-n-go PIRLP from David in less than
1.5 yrs

Not to mention the noise saving, and the reduced fire risk, and not
having to worry about fan failures, and knowing that if anything DOES go
wrong, you can replace a pi with a pi for $20-$30, swap an sdcard for
less than $10, and not have to struggle to find an olde PC that still
has a parallel port in 2020.

Thanks David!   :-)

"Nosey" Nick Waterman, VA3NNW/G7RZQ, K2 #5209.
use Std::Disclaimer;
We have enough youth, how about a fountain of SMART?

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