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31  General Category / General Discussion / Re: Noob question on: July 22, 2014, 07:49:16 am
See Blink Without Delay. Learn it.

Ignore the Blink sketch. It will only teach you bad habits.
32  General Category / General Discussion / Re: Generating Square Wave with with modulated carrier frequency on: July 22, 2014, 07:47:19 am
I am having a hard time understanding what it is you want.

Is that a square wave with a variable width portion on the falling edge that is modulated by some higher frequency? Because all I see are two bright lines.

Can you draw a sketch that clearly shows what you want this to do?
33  Using Arduino / General Electronics / Re: Circuit Correct? Help me! on: July 22, 2014, 07:45:11 am
Tested them how? Just connected and the motor ran? Or measured the voltage while running the motor to make sure it didn't drop by more than 1V?

Obviously, it failed. 4V is -way- too low. Your batteries are either dieing and need to be replaced, or were simply never strong enough.
34  Using Arduino / General Electronics / Re: TRIAC AC switch , need some info on: July 22, 2014, 07:36:02 am
That is drawn a bit strangely. The point between the Load and 220Vac should be the Neutral line, and the line coming out the bottom of 220Vac should be the Hot line.
35  Using Arduino / General Electronics / Re: Circuit Correct? Help me! on: July 22, 2014, 12:47:03 am
How do you know the capabilities of a battery before you buy? Google! Look on the manufacturer's website.

Unless a battery is specifically rated for high current (like rechargeable Lithium Ion or Lithium Polymer), plan on drawing no more than C/2 where C is the AHr (amp hour) capacity of the cells. C/4 is better.
36  General Category / General Discussion / Re: Generating Square Wave with with modulated carrier frequency on: July 22, 2014, 12:41:46 am
I don't get the OP's video.
37  Using Arduino / Project Guidance / Re: Help With Powering/Wiring of a CNC-Style Setup on: July 22, 2014, 12:40:57 am
Yes, that is one of the counter-intuitive things about stepper motors. They may draw less current when they start moving faster.
38  Using Arduino / General Electronics / Re: Circuit Correct? Help me! on: July 22, 2014, 12:39:28 am




Pin 1 Gate to the BJT
Pin 2 Drain to the motor and diode
Pin 3 Source to V+

Looks OK to me. Change the resistors, change the batteries to something larger.
39  Using Arduino / General Electronics / Re: Getting 0-5V with PWM on: July 22, 2014, 12:31:11 am
What about average vs peak? I think he wants the average, not the peak.

Anyway, where is the OP in all this?
40  General Category / General Discussion / Re: Generating Square Wave with with modulated carrier frequency on: July 21, 2014, 09:04:25 pm
That waveform is either badly locked on, or there is something going on.
41  Using Arduino / Project Guidance / Re: Help With Powering/Wiring of a CNC-Style Setup on: July 21, 2014, 08:58:43 pm
I bought a bunch of VGA/RAM heat sinks. Just the right size for the A4988. Many come with thermal double-stick tape on them, if not, buy some.
42  Using Arduino / Project Guidance / Re: How rugged is Arduino? on: July 21, 2014, 08:50:13 pm
Short, clear, code. The hardware affects the reliability, too.
43  Using Arduino / Project Guidance / Re: Poll: How Should I Unlock My Door on: July 21, 2014, 08:48:01 pm
DIY RFID?

http://playground.arduino.cc/Main/DIYRFIDReader

As others have said, the unlock mechanism may take your entire $20.
44  Using Arduino / Project Guidance / Re: How rugged is Arduino? on: July 21, 2014, 08:41:55 pm
Quote
Should i use a watchdog timer for reliability?

Yes, absolutely. Never assume that it can be made to never lock up. ESD, nearby lightning strike, stray cosmic ray, etc.
45  Using Arduino / General Electronics / Re: Circuit Correct? Help me! on: July 21, 2014, 08:14:36 pm
Wow! No wonder your AA batteries are pulled down so far. There is no way they'll supply 1.5A at full voltage, or for very long.
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