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1  Using Arduino / General Electronics / Re: Am I using a LM386N amp wrong? on: September 01, 2014, 06:23:40 pm
The LM386 is not suited for anything other than amplification of signals to a speaker.

I disagree. The LM386 can be used for any purpose for which its characteristics are suited. That includes oscillators, DC amplifiers and motor drivers.

Sorry for to being too specific.

Of course it's usable as a small amp. for motor drive, etc - After all, a speaker is just a motor.

// Per.
2  Using Arduino / General Electronics / Re: Am I using a LM386N amp wrong? on: September 01, 2014, 03:35:08 pm
The LM386 is not suited for anything other than amplification of signals to a speaker.

You should get yourself a LM358 - it's a general purpose opamp, and will do what you want to do.

// Per.
3  Using Arduino / Project Guidance / Re: What Shield or Chip does the GSM library support? on: August 29, 2014, 05:15:52 pm
Almost all GSM modules are controlled using AT-commands.

Almost all the commmands is standardised, and will work across modems. If there is some commands that is different, it would be easy to compare documentation between models, and open the library files and change the AT-strings.

As long as you use modems from the same manufacturer, there is a very good chance that there is absolutely no difference.

// Per.
4  Using Arduino / Sensors / Re: A lot of flowsensors on: August 29, 2014, 05:13:07 pm
If the outputs on the flowsensor is a PWM signal (count pulses per second) AND you can do with measuring a single one at a time, make a network of CD4051 multiplexer chips, then you can read them all.

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

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.
6  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.
7  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.
8  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?

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

// Per.
9  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

// Per.
10  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:
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.
11  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: 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:

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

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:

// Per.
12  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.
13  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.
14  Using Arduino / Networking, Protocols, and Devices / Re: Software implementation of ethernet on: August 24, 2014, 06:00:12 am
Here you go:

// Per.
15  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.
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