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10756  Using Arduino / Installation & Troubleshooting / Re: Voltage regulator getting hot on: April 20, 2011, 03:55:39 pm
 I already answered that.
10757  Using Arduino / General Electronics / Re: Arduino Uno not providing power? on: April 20, 2011, 03:52:50 pm
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this not short or damage atmega328.

Yes it will. To prove it to yourself measure the current you are allowing to flow through that led. Then note that the absolute maximum safe output pin current is 40ma.

Lefty

10758  Using Arduino / Project Guidance / Re: Live Action Scenario Bomb Prop on: April 20, 2011, 03:41:44 pm
Can't you just be happy with a blinking LED like the rest of us?  smiley-grin

By the way if you build one, don't take it to an airport.

Lefty
10759  Using Arduino / Motors, Mechanics, and Power / Re: Driving a solenoid on: April 20, 2011, 03:37:03 pm
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Could it be that without the pull-down resistor to ground (gate to source) when I power up the system, the mosfet could momentarily turn the 12v water solenoid on?  Kinda like the H-bridge without pull-downs on the control pins let a motor 'jump' when powering up?
I don't have pull-downs on my mosfets, but can put them on if this scenario happens.  The mosfet and Arduino will always be on at the same time, other than powering up.

That is the purpose of the pull-down resistor. Recall that an Arduino starts up at power on with all pins as input pins and until the bootloader times out and your sketch sets the pin as an output pin and you set it to low, the mosfet's gate is floating without a pull-down resistor. So adding such a resistor should prevent the momentary activation at first turn on.

Lefty

10760  Using Arduino / Microcontrollers / Re: problem programming attiny45 on: April 20, 2011, 03:31:53 pm
No I'm not, I guess I should do that right? what size cap and where should it be placed?

Jb

You will have to search the posts for verification because I use a hardware programmer and haven't tried to use ArduinoISP as a programmer. I think it's a 10mfd wired between the reset pin and a ground pin, positive lead of cap to reset pin.

Lefty
10761  Using Arduino / Installation & Troubleshooting / Re: Voltage regulator getting hot on: April 20, 2011, 03:28:34 pm
How hot the on board regulators is a function of the following:

External voltage value, 7-12vdc. The closer to 7 volts the better for less heat dissapation.

How much external current any wired components are using of the board's +5vdc power.


Note that voltage regulators like this will automatically shut down if they get too hot or you draw more the it's rated maximum output current. So while hot is not good and should be avoided, it's not likely to damage the board.

Lefty



10762  Using Arduino / Microcontrollers / Re: problem programming attiny45 on: April 20, 2011, 03:20:50 pm
After loading the ArduinoISP sketch are you defeating the board's autoreset feature by using a cap from reset to ground?

Lefty

10763  Using Arduino / General Electronics / Re: Arduino Uno not providing power? on: April 20, 2011, 03:16:55 pm
Quote
Another possibly important detail:
When I connect a wire to the 5V, the green power-LED turns off (and disconnecting the wire turns it on again).

What is the other end of the wire going to? You are somehow shorting the power on the board. Are you sure you are following the wiring correctly. Are you using a resistor in series with your diode?  What value resistor?

Lefty

10764  Using Arduino / General Electronics / Re: Arduino Uno not providing power? on: April 20, 2011, 03:14:46 pm
try to simple put a led direct on pin13 and gnd of arduino without resistor. it works?

Please ignore this suggestion. Wiring a led to pin 13 without a series resistor will short out the output pin and damage the 328 controller chip.

Lefty
10765  Using Arduino / Motors, Mechanics, and Power / Re: Switch 220V/400W lamps with Arduino on: April 20, 2011, 02:09:38 pm
Would it be possible to drive Solid-State-Relays like the Sharp S202 S02 (http://sharp-world.com/products/device/lineup/data/pdf/datasheet/s102s02_e.pdf) directly from an Arduino port? Or do I need a transistor or other driver circuit?

Yes you can use that with an Arduino output pin. The device has an internal optoisolator so you drive it just like you would a led. Arduino output pin to series 250 ohm resistor, other end of resistor to pin 3 of the device, pin 4 of the device to ground.

Lefty

10766  Using Arduino / General Electronics / Re: Arduino Uno not providing power? on: April 20, 2011, 02:04:15 pm
You will have to show us how you are trying to wire up the led (be sure to use a series resistor) to tell you where you might be going wrong. Assuming you can upload to the board and your using the blink sketch it probably isn't a sketch problem, but posting your actual sketch is also a good idea.

Lefty

10767  Using Arduino / Programming Questions / Re: newsoftserial - having a problem sending hex on: April 20, 2011, 11:48:11 am

Instead of: void setServoTarget(int servo, int pos){

Try: void setServoTarget(int servo, byte pos){


I think it's a unsigned byte Vs a signed int problem.

Lefty
10768  Using Arduino / Sensors / Re: Arduino V4 Sensor Shield on: April 20, 2011, 10:13:54 am
Assuming you mean....

http://www.emartee.com/product/41798/Arduino-Sensor-Shield-V4.0

... I see very little there that isn't just a matter of giving you easy connections, on a physical level, to the standard Arduino lines.

There's no "programming" as such. Any code that would work for any sensor or output connected directly will be the same as the code for connecting through the shield.

Now this on the basis of 30 seconds looking at the page cited. I won't be offended... delighted, in fact!... if someone can post any improvements to that answer.

Your assessment is correct. The board is just a kind of break out board allowing for different kinds of connectors to be used to access the arduino pins. Servo compatible pin outs allow for the servo to use arduino power (not a very good idea actually as current is a limited resource on a arduino board) and the analog connectors supply +5vdc to power the sensors as well as route the sensor's output to a arduino analog input pin. There is also a 4 pin communications connector that can be setup for serial or I2C with jumper pins. It's a useful board that is used to support the 'brick' line of sensors sold by Asian dealers.

Lefty
10769  Using Arduino / Programming Questions / Re: Laptop necessary for Serial? on: April 20, 2011, 10:00:44 am
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but I just wanted to make sure that I can run this type of sketch without my laptop attached.

Yes, it will work fine using just external power once you have uploaded a sketch to it from the laptop.

Lefty
10770  Using Arduino / Networking, Protocols, and Devices / Re: >Working, with library!< Interfacing ADS1213 22-bit ADC on: April 19, 2011, 06:37:47 pm
Very cool. Now if some vendor would design a ADS1213 sheild board we would be good to go. I assume 24 bit resolution requires careful board layout and not have to rely on some noisy protoboard or breadboarded lashup.

Lefty

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