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Mk4 Usb Port Problems? Read This.


RChadwick
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I just took measurements to confirm this. If you want to reliably use your MK4 Wifi Pineapple with something plugged into the MK4 USB port, you need to power it with 7 to 15 volts. If you're not using the USB port, you can get by powering the MK4 with 5 volts from a USB port.

The reason is because the hardware uses two separate regulators. One lowers the input to 3.3v the wireless hardware uses, and the other lowers the input to 5V for the USB port. Problem is, these regulators need a volt or two to work. So, if you expect to get 5V out, you need to put more than 5V in. For those interested, here were the results of my quick measurements:

With 5V input, the USB output voltage varied between 3.90V and 4.10V, with no load

With 5.5V input, the USB output voltage was 4.6V, with no load

With 6V input, the USB output voltage was 5.03V, with no load

I didn't plug anything into the USB port (A load), and suspect these voltages will go even lower with a load.

Depending on the USB device you use, it might work with a 5V input, but don't expect it to be reliable.

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Thanks for taking the time with the voltmeter RChadwick! It always good to have the hard facts. The shortcomings of embedded system's USB ports has been a hot topic around here lately - I'm especially disappointed with the raspberry pi's underpowered (and shared pipe) USB's. However, I use a SuperTalent Pico USB stick with my mark4 for days at a time in my lab. Dozens of clients, constant writes with tcpdump and sslstrip. All running off a POE cable from a spare laptop. I don't doubt your measurements, but I have experienced very reliable performance with this card.

Supertalent card:

http://www.supertalent.com/products/stt_usb_detail.php?type=Pico

Super Awesome POE cable:

telot.org/poe.html

telot

telot

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