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Topic: Connect Arduino to Raspberry Pi with Tx/Rx (Read 23035 times) previous topic - next topic

Grumpy_Mike


Grumpy,
In defense of sonny, he pointed out that for $2 you can buy a pre packaged converter from spark fun and not have to buy any other parts, and given it does 4 channels, it could be cheaper than picking up the parts to build one yourself. 

Four resistors an a transistor will cost you $0.10.


sonnyyu

#16
Jun 18, 2013, 07:13 am Last Edit: Jun 18, 2013, 07:21 am by sonnyyu Reason: 1

In the optocoupled approach, can you connect to the emitter side of the optocoupler with a pull down resistor and connect collector to the voltage rail, to avoid the extra transistors that are there to un-invert the signal?  It seems that if you don't enable the pull up on the pin, it would work?  Reason I ask is that I have a boatload of isolators (good deal in bulk  XD). And may have to tie. Pi to a mega


Yes, you can. Here is the answer;-

Current Transfer Ratio/Design Guidelines for Transistor Output Optocouplers

Design Guideline Optocouplers

BTW for just tie Pi to a mega, If I were you just use usb cable via
Quote
Use USB or powered USB hub is more common since this time not only Arduino is powered by Pi but also supported  up to 127 Arduinos same time.
This is the way I did anyway but I did it with few Arduinos same time.

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