With the exception of the Avalon A7 which uses a RPI as its controller, there isn't any Bitcoin miner that is profitable and needs the RPI to control it. The Gridseed is mainly used to mine LTC and it isn't too profitable (maybe a couple pennies if you're lucky). Don't even think about mining BTC with it for profit- when it was released, the miner had below-average efficiency for its time. Now it's just an energy hog and mostly a collectible.
Additionally, if you are talking about Scrypt or other alt coin mining please move this out of Bitcoin mining speculation.
Shall I take it as ,,, THERE IS NO PROFIT WITH BITCOIN MINING

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If i can make 2 or 4$ a day, with mining as profit, that will be great .
How much does your power cost per kwatt?
8 cents a kwatt means you have a chance to profit.
Bitcoin miners are very loud.
The Avalon 741 is about 800 usd. Add a rasp pi and a psu it is near 1000 it make 8 or 9 a day.
Good luck buying it.
Can't you save money by flashing the Pi yourself? I recall I saw a guide for doing that by Avalon and it seems that'd save you a lot over how much Avalon charges. For PSUs you can get a decent server psu that can power it under 100 or rarely 80-50, so it'd be closer to 900 if you're lucky.