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1996  Using Arduino / LEDs and Multiplexing / Re: Suggestion of LED Strip Which Can Be Controlled by Arduino on: July 04, 2013, 04:41:24 am
I wanted to make LEDs turn on and then off in a one-by-one sequence, i.e. running pattern.

I suppose this would be addressable ?


Yes.

I don't think they do single-color, individually addressable strips so you'll have to use RGB.

Next question: How many LEDs do you need per meter?
1997  Using Arduino / General Electronics / Re: Transistor types on: July 04, 2013, 04:35:34 am
BC337 or 2N2222

Remember to put a 330 ohm resistor between Arduino and transistor base.

1998  Using Arduino / General Electronics / Re: Incorrect functioning of Arduino UNO when not connected to Serial on: July 03, 2013, 03:12:37 pm
I have 5V going to the Ping sensor I'm using and 3V going to each motor. The battery pack I'm using is 6V.

Measure it again. 6V isn't enough for the Arduino regulator to function properly so you can't possibly have 5V on the Arduino.

PS: 4 normal batteries doesn't give 6V unless the batteries are brand new. Measure that voltage, too.
1999  Using Arduino / LEDs and Multiplexing / Re: LED frequency issues on: July 03, 2013, 02:37:23 pm
The teensy is powered with 2 3V coin batteries wired in series.

I imagine that's the problem. Coin cells can only provide a couple of milliamps - not enough to run an Arduino + LEDs.

2000  Using Arduino / General Electronics / Re: Incorrect functioning of Arduino UNO when not connected to Serial on: July 03, 2013, 02:33:32 pm
Sounds like a power problem.

Try measuring the voltage on the Arduino.
2001  Using Arduino / LEDs and Multiplexing / Re: LED frequency issues on: July 03, 2013, 01:48:00 pm
Hey all,

I am relatively new to the electronic engineering game. I am currently working to create an LED strobe using the Teensy model 2.0 ++ and am having issues keeping my frequency running. When the Teensy is connected via USB to the computer the code runs fine and the LEDs light up according to the written code with the proper frequency (the teensy and arduino programs don't even need to be open on my computer!). As soon as I unplug the USB the LED's light up with a common illumination without a strobe of any sort. I've changed the power sources but I can't get my LED's to light up properly without the Teensy being plugged into the computer. I can use any help you can offer. Thanks!

Code?
Circuit diagram?

My psychic powers are failing me.
2002  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: July 03, 2013, 01:39:23 pm
I meant to ask: what size cube is possible from only one Arduino? Using only one microcontroller, what size LED cube could I make?
The number of Arduino pins isn't a limiting factor, you could make a very big one with a single Arduino.

But seriously, if you're asking that question then you're not ready to start building 32x32x32 (or whatever). Start with a small one, eg. 4x4x4.
2003  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: July 03, 2013, 01:30:08 pm
I meant to ask: what size cube is possible from only one Arduino? Using only one microcontroller, what size LED cube could I make?

The number of Arduino pins isn't a limiting factor, you could make a very big one with a single Arduino.

2004  Using Arduino / LEDs and Multiplexing / Re: Flickering LED Lamp Problem on: July 03, 2013, 04:38:14 am
a) Take it back to the shop

b) The "Arduino" question was...?
2005  Using Arduino / Microcontrollers / Re: Voltage regulation on Attiny85 on: July 03, 2013, 03:56:58 am
Does bandgap measuring cost extra power?

The ADC needs power, yes. Luckily for us Atmel thought of that and you can turn parts of the chip on/off on demand.

The AVR standard library has functions for this:

http://www.nongnu.org/avr-libc/user-manual/group__avr__power.html

If you're using batteries you should turn off the parts of the chip you're not using. The ADC converter and Timer1 are the worst power gobblers (see datasheet).


It looks like my tiny is working such low voltage.

Don't ever depend on "it seems to work". It might be right on the edge of failure and start giving random errors a week from now when the battery voltage drops by 0.01V.

It looks like my tiny is working such low voltage. Should that V be printed on the chip itself (or a serial)?

It should say "ATtiny85V" on the chip.
2006  Using Arduino / Microcontrollers / Re: Multiple power supplies on one Arduino board? on: July 02, 2013, 06:23:30 pm
Can you power any of the Arduino boards with both the power supply outlet and the Vin pin and power them both to 12V?  Or if my battery was dying but I didn't want to wast it so I used my DC power supply through the Vin pin to make up for the loss in power?

Connecting a 12V supply to a dying battery isn't a good idea.
2007  Using Arduino / Microcontrollers / Re: Does the 1.1V analog ref work on the Attiny85 ? on: July 02, 2013, 02:45:32 pm
I'm using: http://hlt.media.mit.edu/?p=1229 which does not list it so I guess I'm out of luck unless I can use C code directly ?

Direct programming AVR chips is easy. For the ADC you only need to manipulate three registers.

Code:
ADMUX = XXXX;   // Select a source
ADCSRA = 0xd0;  // Start a conversion
while ((ADCSRA&0x10)==0) {
  // Wait for conversion to complete
}
int val = ADC;  // Get result

(Or something like that ... I just typed that with no testing, see datasheet...)
2008  Community / Exhibition / Gallery / Re: noise resilent DCF77 clock on: July 02, 2013, 02:02:57 pm
Well, IMHO it is pointless to make an Arduino a NTP Server, this is something that should be done with a RASPI.

Why? I could do it with a Tiny85 and a cheapo Ethernet module for less money and in a much smaller space.
2009  Community / Exhibition / Gallery / Re: Classic 70's TV game reproduced on the Arduino/AMTEGA328 on: July 02, 2013, 01:58:17 pm
...seems to indicate that such LEDs don't readily exist - but then again, I've seen home-use UV LED based sanitization wands...?

I've seen home-use ultrasonic mosquito repellants and UV-led mosquito zappers on sale. It doesn't mean they actually work.

PS: Is there anything they don't sell ultrasonic repellants for? Rats, cockroaches...I've seen those too. None of them work BTW.

I used some 3W UV LEDs to light up a room last Halloween. I'm sure one of those placed right on the EPROM window would do something to it. You'd have to experiment to find out how long it takes to erase using one of those.

2010  Community / Exhibition / Gallery / Re: Classic 70's TV game reproduced on the Arduino/AMTEGA328 on: July 02, 2013, 01:52:05 pm
I've got a stack of old 6809s and Z80s  too...I'm getting twitchy asm fingers.
However, before I could program my EPROMs (for which I'd have to build a programmer), I'd have to erase them.
I wonder if UV LEDs would do the trick?

The wavelength for UV erasers is 253.7nm. I don't think you can get LEDs with those wavelengths.

Other wavelengths will work but it will take longer to erase.

https://en.wikipedia.org/wiki/EPROM#Details
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