I am new to this and in the process of building a prusa with sanguinololu 1.3
as printer controller, using a raspberry pi as host controller.
When checking the wiki, I came across the usb 5V bug mentioned on
http://reprap.org/wiki/Sanguinololu#Bugs
The solution mentioned there and googled elsewhere (desoldering the 7805 or cutting the 5V track) seemed a bit drastic
for my brand new controller board I have received only this week.
I searched elsewhere and came across a similiar problem people seem to be having with raspberry pi - some powered usb hubs backfeed 5v into the raspberry pi. That "feature" can apparently be used to power the raspberry pi, but it can just as well cause all sorts of usb problems.
An entry in a german raspberry forum seemed promising and gave it a try.
http://raspberrycenter.de/forum/leid-usb-hubs
There was suggested a little adapter that cuts the usb 5v line - but, being an adapter, it can be used with some
flexibility (well, you can use it or not use it, but you have a choice and the choice can be changed even after you have made it)
I built two of these adapters today, basically just a type A usb plug and type A socket soldered together back-to-back, but with only pins 2-4 connected and pin 1 (5V) not. The gap I have filled with hot glue so the pins are protected. The cost was about 0,50 EUR per adapter, but the socket und plug could just as well be salvaged from an old computer and broken usb stick.
What can I say: these adapters seem to work really well. I connected both of them to my raspberry pi. The powered usb hub is connected to the first, the sanguinololu to the second. Both the sanguinololu (the first time I saw my steppers move) and the usb hub for the raspberry seem to be working ok. What is more, the usb problems I kept having on my raspberry for ages seem to have gone, I could even connect a second usb hard disk via the hub, which was a first.
Sorry, if this is an answer to an obvious f.a.q. but I haven't found the solution with the adapter in the forum so far.
as printer controller, using a raspberry pi as host controller.
When checking the wiki, I came across the usb 5V bug mentioned on
http://reprap.org/wiki/Sanguinololu#Bugs
The solution mentioned there and googled elsewhere (desoldering the 7805 or cutting the 5V track) seemed a bit drastic
for my brand new controller board I have received only this week.
I searched elsewhere and came across a similiar problem people seem to be having with raspberry pi - some powered usb hubs backfeed 5v into the raspberry pi. That "feature" can apparently be used to power the raspberry pi, but it can just as well cause all sorts of usb problems.
An entry in a german raspberry forum seemed promising and gave it a try.
http://raspberrycenter.de/forum/leid-usb-hubs
There was suggested a little adapter that cuts the usb 5v line - but, being an adapter, it can be used with some
flexibility (well, you can use it or not use it, but you have a choice and the choice can be changed even after you have made it)
I built two of these adapters today, basically just a type A usb plug and type A socket soldered together back-to-back, but with only pins 2-4 connected and pin 1 (5V) not. The gap I have filled with hot glue so the pins are protected. The cost was about 0,50 EUR per adapter, but the socket und plug could just as well be salvaged from an old computer and broken usb stick.
What can I say: these adapters seem to work really well. I connected both of them to my raspberry pi. The powered usb hub is connected to the first, the sanguinololu to the second. Both the sanguinololu (the first time I saw my steppers move) and the usb hub for the raspberry seem to be working ok. What is more, the usb problems I kept having on my raspberry for ages seem to have gone, I could even connect a second usb hard disk via the hub, which was a first.
Sorry, if this is an answer to an obvious f.a.q. but I haven't found the solution with the adapter in the forum so far.