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HawaiianPi
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Location: Aloha, Oregon USA

$9 Wireless Pi computer

Mon Jun 27, 2016 11:16 pm

Combine a $4 USB Wireless b/g/n adapter + $0.40 (40¢) OTG adapter + $5 Raspberry Pi-Zero:

Image

..and you get...

Image

A wireless Linux computer for less than ten bucks!

(click on pictures for larger versions, then use back to return here)

Yup, I finally got my Pi Zero. :mrgreen: And I even love that the WiFi adapter is a naked board sticking out of a USB plug, because it matches the Zero! Not sure what I'll be doing with it yet. Thinking about picking up a camera and cable. I have a couple of small powered USB 2.0 hubs kicking around here somewhere, might try it as a low powered server. Or a mini game system. Or a tiny media center. Or a torrent seeder... Too many ideas, not enough Zeros...

Now where are my 2x20 headers... :ugeek:
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

stderr
Posts: 2178
Joined: Sat Dec 01, 2012 11:29 pm

Re: $9 Wireless Pi computer

Mon Jun 27, 2016 11:52 pm

HawaiianPi wrote:A wireless Linux computer for less than ten bucks!
Ignoring the power supply wart or whatever and the flash card to boot. If the zero could just take 20 volts or something like that unregulated, almost any 12 volt wall wart would power it and actually could probably be used to power a few of them in parallel. This change and built in network boot capability would once again change the cost game.

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HawaiianPi
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Location: Aloha, Oregon USA

Re: $9 Wireless Pi computer

Tue Jun 28, 2016 12:18 am

stderr wrote:Ignoring the power supply wart or whatever and the flash card to boot. If the zero could just take 20 volts or something like that unregulated, almost any 12 volt wall wart would power it and actually could probably be used to power a few of them in parallel. This change and built in network boot capability would once again change the cost game.
I already own a ridiculous number of 5V chargers and power supplies, so didn't need to get another one. I also have a handful of microSD cards, so didn't need any more of those either. Already had the tiny OTG adapters too (and a few not so tiny ones that came with various phones or tablets). And speaking of phones, I even have a couple of those mini-HDMI to HDMI adapters from phones past.

All I really needed was the Zero and a way to connect it to my network, so... $9 wireless Linux computer (well, okay, there was some shipping too).

I've even got a bunch of CP2102 USB-UART serial adapters, somewhere (still haven't finished unpacking from the move). Been meaning to find those and try the serial console feature.

I agree on network boot, that would be nice.

Don't think higher voltage would be beneficial, since 5V power is so commonplace nowadays. And unlike the Pi3, the Zero can run off of almost any 5V supply. Mine draws less than 200mA when connected to my wireless network. I think the weakest 5V charger I've seen was 380mA, which came with a Bluetooth headset, and I'll bet even that could power a Zero.

... I found my 2x20 headers! :D
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

stderr
Posts: 2178
Joined: Sat Dec 01, 2012 11:29 pm

Re: $9 Wireless Pi computer

Tue Jun 28, 2016 4:37 pm

HawaiianPi wrote:Don't think higher voltage would be beneficial, since 5V power is so commonplace nowadays. And unlike the Pi3, the Zero can run off of almost any 5V supply. Mine draws less than 200mA when connected to my wireless network. I think the weakest 5V charger I've seen was 380mA, which came with a Bluetooth headset, and I'll bet even that could power a Zero.
My supply of wall warts that would work if the pi could take higher than 5v is probably 100 to 1 more than now. And the zero is a special case because you can't run most of the pi on chargers that put out 380mA.

The makers of the ATX power supply standard came to the same conclusion about 5v and lower and went to mostly 12 volts. They decided that power supplies make 12 volts and hardware then decides what it wants to do with it. This is a new thing but cheap dc to dc conversion is now readily available.

If it didn't much matter what the voltage was to the pi as long as it was more than 5v and less than say 20v, whatever the max is from an unloaded 12 volt unregulated wart, then people could build, keeping in mind current limits, their own power over ethernet and their own, I don't know, call it power over two wire bus, supplies.

So, for example, if I wanted to have 10 pi zeros with cameras set up for a security system, I could use a cheap 12 volt power supply designed for low voltage outdoor lighting, and run the two wires out and tap into it at each pi. Compare to what I'd need to do today for the same outcome, yea, mains out to each pi and a 5v wart for every one to convert. Not only does this involve high voltages, it means the obvious reliability issues of dodgy wall warts in potentially high current continuous duty applications. No, I think this capability would be huge, right up with the booting from the ethernet/wifi fantasy.

geoffr
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Location: Melbourne, VIC

Re: $9 Wireless Pi computer

Wed Jun 29, 2016 3:13 am

stderr wrote:
HawaiianPi wrote:Don't think higher voltage would be beneficial, since 5V power is so commonplace nowadays. And unlike the Pi3, the Zero can run off of almost any 5V supply. Mine draws less than 200mA when connected to my wireless network. I think the weakest 5V charger I've seen was 380mA, which came with a Bluetooth headset, and I'll bet even that could power a Zero.
My supply of wall warts that would work if the pi could take higher than 5v is probably 100 to 1 more than now. And the zero is a special case because you can't run most of the pi on chargers that put out 380mA.

<snip>
One way to deal with that problem is to use a cheap DC-DC buck converter - e.g.
http://www.dx.com/p/321489
http://www.dx.com/p/255394

I've used a couple of these to power multiple Pis off a single 12V DC power supply.

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mahjongg
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Re: $9 Wireless Pi computer

Wed Jun 29, 2016 5:53 pm

stderr wrote:
HawaiianPi wrote:A wireless Linux computer for less than ten bucks!
Ignoring the power supply wart or whatever and the flash card to boot. If the zero could just take 20 volts or something like that unregulated, almost any 12 volt wall wart would power it and actually could probably be used to power a few of them in parallel. This change and built in network boot capability would once again change the cost game.
a 12Volt to 5Volt converter (for say 1.5A) would add a few dollars to the price of the PI, would produce heat, and the most important problem, there is no guaranteed, no errors possible, 12Volt input connector that prevents polarity inversions. Don't say a barrel connector, as it is not a standard, and doesn't prevent disasters from happening, like plugging in a 27Volt input power, or one with reverse polarity, or even AC.
Just standardizing to a micro-USB has solved all those problems.
Adding network booting is only possible by changing the tiny ROM for the GPU inside the chip to a much larger one, is not going to happen!

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