Using the raspberry Pi 2 mod B to programming arduino with a usb externally powered hub

To:AS

I do not have a Arduino Uno R3, but I think pictures that I have seen of it, has a Female (2.1mm?) Receptacle for a DC Power connection in the Lower Left Hand Corner. I believe the spec for a Power Brick is like 5-12VDC. You should check this. I think that the Arduino Uno R3 might draw DC power from RaspPi's USB Connector's (+,-) Leads, enough for a LED but not a heavy load like a servo. I know your first inclination was to get a powered  Hub, which you tried. IDK (I Don't Know) if the Powered Hub WILL definitely power your Arduino Uno R3 (w/ Servo attachment). Try a Power Brick on the Arduino Uno R3's power connector. IDK2 how the Arduino Uno R3 will switch from drawing power from the USB connection and switch(?) to the Power Connector. Please read any instructions you have on the Arduino Uno R3 first.

I am in NY NY, USA and just yesterday {Time Stamp 22FEB16] I bought (1-qty) Inland (brand) Mega 2560 r3 [price was $9.99USD down from $19.99], and (1-qty) Inland Pro Mini 5v [price was $3.99 down from 7.99]. AAR (At Any Rate). This was at a Micro Center Store in the Queens neighborhood of NYC. IDK3 whether MC is placing these items on Sale OR Clearance?. The items where in the section that they normally have stuff for RaspPi and Arduinos, NOT in the Clearance Racks. I bought these two items as an "Impulse Buy", I don't really need them, but the Price was Right.

Now I have Three Arduino Variants: 1. Gertduino. 2. Mega 2560 r3, 3) Pro Mini 5v. I will be connecting RaspPi to Gertduino and using MatLab/Simulink. Will post Schematic Block Diagram when done IF you guys/gals want.

As a possible Post-Mortem  to this Thread, We (all contributors) have been kicking-around your situation for Ten Days now. If a schematic Block Diagram (of your situation) was posted in the beginning, we could have been at this point maybe 1-2 days after your Original Post. Just a Thought. No Judgement.

USCDADNYC (NY NY USA)

Aditya Salunkhe wrote:

 

Yes connecting directly to rpi works but the main problem why i bought the externally powered hub was because of current drops in rpi when arduino is connected

for eg.

>if i have a arduino with a load(like a servo) connected to raspberry pi's usb there are current drops in rpi and rpi freezes

>but if i have a small load connected to arduino(like a LED) everything worked fine

Hence i thought this could be a Amp problem so.. i bought a externally powered hub.

Aditya Salunkhe

     Ok, I see better what and why,  Here is my final points:

• Originally without hub(powered), you had a RPi powered off wall with Arduino power off  the RPi. This works until a Servo is powered off Arduino and then you see/would see a current drop on RPi .
• You purchased a USB 3.0 powered hub to fix. But when you power the arduino through hub, the RPi cannot see the Arduino, See next point.

• > ohh and one thing i noticed usb keyboard or mouse or any other HID device wont work with rpi when plugged into USB hub but storage devices like external HDD and flash drives work with hub // hub is fine tho i checked it on other system it works fine.

     This means any human interface or for that matter the Arduino (which btw is another human interface since it uses a serial connection to the RPi) does not work on the powered hub does not work with RPi because the RPi is USB 2.0 and the powered hub (USB 3.0) is not fully backward compatible with 2.0!

     So with this dilemma, how can you "fix" the situation with following options:

1. Power servo not from Arduino, but from some other power source. I am surprised it powers of Arduino in a way.Use HUB for storage only.
2. Power RPi off powered hub. Connect Arduino to RPi directly. Read https://www.arduino.cc/en/Main/ArduinoBoardUno which suggests way to switch Arduino to use external power off wall jack in range of 7V to 12V.
3. If number 2 does NOT work, use a data only USB from Arduino to RPi http://yourfinalsystem.com/cable-design-f-a-q/147-how-do-data-only-usb-cables-workto force Arduino to power off wall.Uou can make one by cutting the +5V wire only leaving GND.
4. Replace your 3.0 powered hub with a true 2.0 powered hub that is compatible with RPi RPi VerifiedPeripherals - eLinux.org

I tried to be thorough but concise.

Thanks,

Clem

Kudos to CM again (what is your physical loc and LocalTime again?)

1. Your Tip "... Read https://www.arduino.cc/en/Main/ArduinoBoardUno which suggests way to switch Arduino to use external power off wall jack in range of 7V to 12V....". Was something I was (half-way) looking to find out in case my Mathlab/Simulink-RaspPi-Gertduino Set-up does not work. Thx for the URL

2. Your Tip #3 "...cutting the +6V wire only leaving GND..." I think if you do a Wiki on"USB", I don't think they refer to this Wire as "+6V". I think they label it as "+".or "V_CC (+5 V, red wire)" I do not want AS to get confused.

BTW since you are knowledgeable about Arduino, Maybe you can direct me to URL's that describe: FTDI cable, AVR (USB Programmer) Cable, I2C(spelling?) Cable?

I think they are about the same . In that they are required if your Arduino VARIANT does not have a Full Size USB B female connector, and you want to program the Variant.

THX in advance

USCDADNYC (NY NY USA 6:43AM EST)

thanks i will try cutting power line from usb, to power arduino from wall

To AS:

Pls post what you did/going-to-do WRT the powering your Arduino Uno R3. Did/does the Arduino Documentation have something more specific than (possibly) Cutting pin 1 of the Full Size Female type -B Connector w/ signal designation "+" (5v)? AAR I do not have a Arduino Uno R3. I do have a Arduino Variant, an Inland-brand Mega 2560 r3. This has less documentation than Real Arduinos.

BTW (I have a 26pin GPIO RaspPi) to able to measure the Current requirements of your Arduino Uno R3, try buying a 40pin Pirack. My (26pin) Pirack Board has (jumpers) that you can bridge w/ an Ahm-Meter. IDK the p/n for the 40pin version, BUT the 26pin version IS; Manf: PiFace Newark P/n 97W2503 Manf p/n Pirack

BTW2

[Time Stamp 29FEB16 10:11AM EST] They just announced a RaspPi 3. This is a Game-Changer, b/c this RaspPi 3 has BT (BlueTooth). If a new (incarnation) of RaspPi Zero has

BT, Then ALL BETS ARE OFF! The lack of wireless connectivity had forced us to use Microcontrollers. Not anymore, if a new RaspPi Zero includes BT. Any new RaspPi Zero including BT coupled w/ a RTC module for RaspPi (connected via GPIO Pins), will be a Great Combo. So await/Lobby-for a RaspPi Zero w/ BT