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Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 3:08 pm
by sunng
I'm using a TP-Link USB Wifi for my raspberry pi. In my case, the network gets very weak when touchscreen is on. It can discover my WiFi but never dhcp successfully. When I turn off the touchscreen everything works as before. So I assume this is a power issue.

So do you use any Wifi adapter together with the display? Does it work? Is it because my USB Wifi uses too much power? Do you have some recommendation if I buy a new one?

Thanks!

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 3:59 pm
by JimmyN
It's most likely a power issue. The display draws another 430mA~450ma so it's probably pulling voltage down some and the wireless adapter doesn't have enough power. I use 2 different wireless adapters with mine. One is an Edimax I don't remember the brand on the other one, but it works fine with either. What kind of power supply adapter are you using and do you ever see any low voltage indications on the RPi, like the colored block in the upper right of the screen or a blinking red power LED?

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 4:05 pm
by sunng
Yes, I do see that block on the screen. I didn't know thats a low power indicator.

Thanks for your suggestion. I will switch to an Edimax then.

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 4:19 pm
by JimmyN
Changing the wireless adapter may not help. Your power supply may not be up to the job with the display drawing almost another half amp in addition to the RPi. Unplug the wireless adapter and play with it for a bit to see if you still get low voltage indications. Plus try a reboot without the wireless adapter and watch to see if you get any low voltage indications while it's booting up.

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 4:38 pm
by fruitoftheloom
JimmyN wrote:Changing the wireless adapter may not help. Your power supply may not be up to the job with the display drawing almost another half amp in addition to the RPi. Unplug the wireless adapter and play with it for a bit to see if you still get low voltage indications. Plus try a reboot without the wireless adapter and watch to see if you get any low voltage indications while it's booting up.
You need a decent 52A PSU

https://www.raspberrypi.org/products/un ... wer-supply

Then you can increase the USB BUS from 600ma to 1200ma if you have a RPi B+ / 2B

https://projects.drogon.net/testing-set ... erry-pi-b/

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 5:15 pm
by rpdom
fruitoftheloom wrote:You need a decent 52A PSU
While that would work, I suspect it is a bit of overkill :lol:

Keyboard sticking? (I should talk... mine is in a right state. It needs some serious TLC and cleaning. I have to check everything I type twice :( )

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 5:18 pm
by mahjongg
I suspect by 52A he meant 5V 2A. Not over 50 Amperes. ;)

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 5:19 pm
by fruitoftheloom
mahjongg wrote:I suspect by 52A he meant 5V 2A. Not over 50 Amperes. ;)
Yes my keyboard can not type :oops: :oops: :oops: :oops:
5V 2A

Re: Anyone using wifi together with the display?

Posted: Fri Oct 23, 2015 10:16 pm
by W. H. Heydt
sunng wrote:Yes, I do see that block on the screen. I didn't know thats a low power indicator.

Thanks for your suggestion. I will switch to an Edimax then.
It's not exactly "low power", rather, it's "low volage". I realize that is a bit of a nitpick because a PSU under load or a poor cable will drop the voltage giving that result.

I've been using a Monoprice dongle without any issues, but I make very little use of WiFi...generally I only use it at Jams, so roughly 3 -4 hours once a month outside of some occasional testing.