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1  Using Arduino / Networking, Protocols, and Devices / Re: Stuck with RTC on I2C. on: August 26, 2014, 02:46:30 am
Folks,

All working.

Found the problem/s.

I'm a step further forward now.

Are you going to share what the solution to your problem was, so other people can benefit from your posts ?

// Per.
2  Using Arduino / Networking, Protocols, and Devices / Re: I2C bus running at 100kHz and 400kHz at same time? on: August 26, 2014, 02:44:46 am
As a test I commented out TWBR = 12; and the bus stays at 100MHz now.  And the OLED display still works.

100 KHz smiley-grin

Sure it still works, it just takes 4 times as long to send data to it. if it's not an issue for your application, let it be like that.

Otherwise, nice find - i would never expect to see something like this happen - i'm wondering what a slow 100 KHz-only device on the bus would get out of the 400 KHz signaling...

// Per.
3  Using Arduino / Networking, Protocols, and Devices / Re: Shield UMTS on: August 26, 2014, 02:40:50 am
How about a 3G-modem (USB-stick) in a USB Host Shield ?

// Per.
4  Community / Products and Services / Re: IDE recognizes Uno R3 board as Duemilanove on: August 24, 2014, 11:11:13 pm
So, I would need another ATmega328P?
http://arduino.cc/en/Tutorial/ArduinoISP

If I don't reprogram will anything be impacted?


You can use it as it is now, or re-flash the bootloader with something like this
http://www.ebay.com/itm/321455871442

// Per.
5  Using Arduino / Programming Questions / Re: One Wire & Dallas Temperature on: August 24, 2014, 02:09:36 pm
Please use the #code tag for your code, like
Code:
this

// Per.
6  Using Arduino / Motors, Mechanics, and Power / Re: Power an e300 Electric Razor Scooter from an AC Source? on: August 24, 2014, 10:29:49 am
Thanks, a slip ring looks like a great way to go to keep the cord from getting tangled.
I'm still wondering how to convert AC wall power to replace the DC batteries.
I'm wondering if I can basically take an AC to DC converter like this:
http://www.amazon.com/12-Volt-Power-Supply-Standard/dp/B00B8TRF0A/ref=pd_sxp_grid_i_0_2
and run the positive/negative outputs to the battery leads into the scooter?
Any thoughts?

Yes you can do that. But expect the motor to draw in excess of 40A when accellerating, and that would render your power supply useless. If you are lucky, it wille shut down and protect itself - if not, it will break down.

// Per.
7  Using Arduino / Motors, Mechanics, and Power / Re: Need help with RAMPS (reprap 3d printer shield for mega) on: August 24, 2014, 10:25:21 am
I have four steppers in total. My three axis drive motors are these:
http://www.ebay.com/itm/NEMA17-17-Stepper-Motor-36oz-in-2600g-cm-3D-Printer-RepRap-Medel-Prusa-/331084351443?pt=LH_DefaultDomain_0&hash=item4d162a47d3 They are 12v and 0.4 amps/phase. I have 3 sparkfun easydrivers to drive them if needed. My extruder motor is five volts 0.84 amps/phase. Lastly, the RAMPS controller I bought a-la-cart here: http://www.ebay.com/itm/111322422790?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Those motors are a very bad selection for a 3D-printer. To get speed and torque, you need a much lower voltage-motor.
like this http://reprap.me/hardware/nema17.html

If you want to use those 12V-motors you need to power your RAMPS board with 24V - check with the manufacturer to see, if your board can handle this. Still it will not be very good, compared to the very low-voltage motors like the one i linked to.

Some reading: http://www.selene.co/Blog/2011/07/stepper-motor-voltages-explained/

// Per.
8  Using Arduino / General Electronics / Re: Using multiple ESC on arduino mega on: August 24, 2014, 08:01:31 am
I simply want o know will the ECS draw current from my board if use a power source ohter then the BEC from the ESC. 

They will not draw current. Simple as that.

The signal from Arduino is a logic-level signal, and only a few mA is taken from the Arduino.

// Per.
9  Using Arduino / General Electronics / Re: Using multiple ESC on arduino mega on: August 24, 2014, 07:00:11 am
It's quite simple. You treat the ESC's like Servo's.

If your ESC's have a built-in BEC or SBEC and the output voltage is maximum 5.5V, you can power your Arduino trough one of the ESC's as well - usually they will have a 6V-output so check this first, before destroying your Arduino. 6V is not enough for the Raw-pin(DC-in-jack)

In either configuration, you connect the black wire (GND) to Arduino's GND, and you connect the signal-wire to an Arduino output, set in your code.

Do not connect the third power-pin, unless you want to power your Arduino this way.

// Per.
10  Using Arduino / Networking, Protocols, and Devices / Re: Software implementation of ethernet on: August 24, 2014, 06:00:12 am
Here you go: http://bit.ly/1mDmujk

// Per.
11  Using Arduino / Project Guidance / Re: How to power the Arduino from a UK light switch on: August 23, 2014, 11:00:31 am
Absolutley not.

Lightswitches in uk no not have a neutral.

If you use the earth the very best situation would be you trip a leakage breaker if you have one.
They are not connected to lighting circuits in domestic situations any way.

Worst case various electrical devices in home will suddenly become live wrt local earth, FATAL.

Wrong. In an UK outlet there is Phase, Neutral and Earth.

Still, unless EXACTLY you know what you are doing (and then you wouldn't ask here) i would not recommend to try it. It can go so very wrong.

// Per.
12  Using Arduino / General Electronics / Re: R5 on LCD broken? on: August 23, 2014, 10:00:28 am


Will using the wrong value damage the display? I soldered a 4.7 k in and the display seems to work just fine, although the OFF segments are a little uneven in their darkness. That's something I can live with if that's the only effect it will have.
Yes, using the wrong value will potentially damage the display because it will introduce a DC bias to the excitation voltages.  If you genuinely perceive a difference in the behaviour, that is your proof.  A DC bias would - amongst other things - show up as uneven illumination of the "OFF" segments.

I would guess, that the small imbalance in the bias (in the scope of a 3$ display), it wold not be the end of the world. If something did happen in the long run.

If one of the resistors of the stepped voltage-divider is off, i would think the others would change too, rendering the net bias even.

I have no personal experience with muxed displays, i only designed circuits with static backplanes.

// Per.
13  Using Arduino / General Electronics / Re: R5 on LCD broken? on: August 23, 2014, 06:05:34 am
Will using the wrong value damage the display? I soldered a 4.7 k in and the display seems to work just fine, although the OFF segments are a little uneven in their darkness. That's something I can live with if that's the only effect it will have.

No, no real harm should happen, as the segments are still driven with AC-signals. The only thing that will hurt the LCD-glass is DC.

Put the 4k7 on the board, and order the correct replacement.

// Per.
14  Using Arduino / Installation & Troubleshooting / Re: Arduino Uno Overheating on: August 23, 2014, 04:33:18 am
PLEASE resize that picture. It completely fucks up my browsers.
No more than 1000 pixels on the longest side, thanks.

Also, what does the specification for the "LED amplifier" state about the inputs?

If you don't have any documentation, open the box and take a good, clear picture of the internals. Resize the picture o maximum 1000 pixels on the longest side, and post it here.

// Per.
15  Community / Products and Services / Re: IDE recognizes Uno R3 board as Duemilanove on: August 22, 2014, 03:49:22 pm
The manufacturer loaded the wrong bootloader into the chip.

Attach an ISP-programmer and do a "burn bootloader" with the Uno selected - problem solved.

// Per.
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