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1  Using Arduino / Project Guidance / Re: Green Laser 3VDC Ebay on: April 22, 2014, 02:00:34 pm
Krupski gets the cigar on this one!  (those green dpss modules will handle 6volts from four AA's just fine).

I think I would try a MOSFET, but he's got it.
2  Using Arduino / Project Guidance / Re: ArPReS - Arduino Parachute Release System - Brainstorming on: April 22, 2014, 01:55:38 pm
1) how are you going to tell the difference between change in Baro induced by wind, prop wash, or normal aerobatic flight and loss of altitude due to catastrophic failure of the copter?
(hint: putting a foam buffer over the hole in the baro will take care of the first two, most of the time)

2) how are you going to throw the chute clear of the aircraft when deployed (are you familliar with the term 'cannon-balling')?

might want to look into an accelerometer and think about a solenoid?
3  Using Arduino / Project Guidance / Re: Green Laser 3VDC Ebay on: April 22, 2014, 08:53:26 am
Gimme a Break!!

50mW greenie e-bay laser = DPSS, prob > 50mW = prob 200mW or better IR pump diode.

No wonder the Arduino 3.3V supply couldn't get it to threshold current.......
4  Using Arduino / General Electronics / Re: can i put leds on serial line to show activity? on: April 18, 2014, 12:09:01 pm

You put the LED and current limiting resistor between the Arduino pin and ground,, and the LED 'Sinks' (draws) power from the Arduino when the pin goes high ( the Arduino sources power to the LED).

You put the LED and resistor between +5Vdc and the Arduino pin,, and the LED 'Sources' power, from +5Vdc, to the Arduino pin when it goes low ( the Arduino sinks from the LED).

I think,,, My brain hurts....
5  Using Arduino / Project Guidance / Re: Blocking -VDC on: April 17, 2014, 02:07:55 pm
First prize to Polymorph for thinking outside of the box!!
6  Using Arduino / Project Guidance / Re: Blocking -VDC on: April 17, 2014, 01:31:23 pm
Instead of asking the sensors (polling), what about having the sensors alert you (interrupts)?
7  Using Arduino / Project Guidance / Re: Blocking -VDC on: April 17, 2014, 11:06:31 am
Encoder wheel setups use some sort of emitter/detector  (photo interrupter, magnet/hall sensor,,,,) to generate pulses which are used by subsequent circuitry (to, say, measure rotational velocity, or positioning).  Make it easy and consider a photo interrupter and an encoder with just one shadow (or window, depending upon trigering strategy,, we'll use a shadow). When the shadow passes through the interrupter fixture, it blocks the I.R. beam and provides for the generation of a pulse (for simplicity forget about the second pulse when the shadow leaved the slot).  You count that pulse over time and get a rudeementary rotational velocity.  End of Encoders 101 class.

If you place two interrupters along the wheel, you can detect which gets interrupted first, and determine direction of rotation, and some other stuff, like speed and velocity changes,, all kinds of goodies.
It just takes a little logic.
8  Using Arduino / Project Guidance / Re: accelerometer readings on: April 17, 2014, 10:41:12 am
How about telling us which accelerometer you are using and/or supplying a link to the data sheet?
Accelerometers I am familiar with report in G's (gravity), not degrees.
9  Using Arduino / Project Guidance / Re: How can i connect Laser Diode to Arduino? on: April 15, 2014, 01:47:41 pm
The circuit you posted is called a DDL driver, after the fellow who originally posted it on  It is a modified constant current regulator, based upon a linear voltage regulator IC configured as a current regulator.  Not real efficient (%power in vs. %power out), but perfectly servicable for the diodes in question, IF,,,, you know the threshold current of your LASER Diode, and, the Maximum Rated current of your diode, and how to set the current limit of the driver to a value somewhere in between, and, of course, what kind of diode you have.

You said you recovered it from a CD driver (what is that?),  If you got it out of a CD-ROM reader, it is a useless I.R. Useless, to low power to really do any burning, and hazardous to play with because it is invisible emission.  If you got it out of a CD Read/Write Drive, it could be the READ diode (which is a useless I.R.), or the WRITE diode ( a moderate to low power RED diode).  If you got it out of a DVR writer, it gould be the same as a CD-ROM drive (except the RED will be a little more powerful).  Then there's BlueRay,,,,,

I.R. LDs are mostly 2.2v fwd, case positive
RED, and BLUES, are about 4-5v fwd and case negative.

You need the diode, a mounting with a heatsink, a driver and a power source.  A Arduino ain't gonna cut it as a power source, and the DDL does not have an added Modulation circuit.  You COULD use the arduino to drive a power MOSFET or HEXFET as a power switch between the power source and the driver positive feed (pretty expensive switch).  You would need to set the driver current limit with a test load, turn off power, disconnect test load, short the driver's output cap to discharge, THEN connect the diode.
Observe Static Electricity precautions.

Anybody who suggests that you use a resistor as a current limitter is uninformed or a fool.  Your diode won't survive long in that configuration (especially if you try to run it close to max current).

Go to LaserPointerForum, or some other laser forum, and do a lot of reading before you proceed with this project.  

Then again, free advice is worth every penny you pay for it.  Do your research first, or suffer the consequences.  Your choice.
10  Using Arduino / General Electronics / Re: can anybody tell me the gain of this transistor for 0.15 amp collector current? on: April 14, 2014, 02:38:26 pm
Since when is .15Amp = 15mA????
11  Using Arduino / Project Guidance / Re: Building a lightweight quadcopter on: April 14, 2014, 12:18:28 pm
Then again, you're gonna need a copter to learn how to fly one.  Most of them are not really ready to fly right out of the box.  But, it would be a fair idea to invest $50 or so in a mini and attempt to learn to fly it.
12  Using Arduino / Project Guidance / Re: Arduino frequency counter on: April 14, 2014, 12:14:31 pm
Freqcount.h is NOT a library, it's a C Header file.  The Library which contains that file is accessable at the link CrossRoads gave earlier, look for "Download: (version 1.0) " on that page.
13  Using Arduino / Project Guidance / Re: Building a lightweight quadcopter on: April 14, 2014, 11:17:59 am
Brushless will last much longer, are more efficient, and offer a much wider range of ESC's.
Arduino Uno is more than sufficient for basic multicopters.
Cannot say about the shields.  HobbyKing offers MultiWii controller boards which incorporate Gyro's, magnetometer, Accellerometer, and will support other modules, such as GPS, for about $30 US (but shipping is really costly).

Before you start pulling parts together, consider:
Foamie may not take the stress without additional structural support (wood, rigid plastic, or metal).
In my limited experience, the lighter the bird, the harder it is to stabilize.  design heavy and it will be easier to add things like camera and gimble later.

Also, you might consider starting with a tricopter design first, much, much, easier to tune and balance (IMHO).

Good Luck and enjoy!
14  Using Arduino / General Electronics / Re: Switching 220V light bulbs on: April 08, 2014, 09:32:14 am
Can you spell TRIAC?
15  Using Arduino / Project Guidance / Re: Putting a display on MAX038 on: April 03, 2014, 10:26:54 am
With respect Crossroads, that post has nothing to do with a MAX038 (what the OP is asking about).

However, having given up on the grandeos MAX038 based 'variable frequency microcontroller controlled waveform generator, with frequency read out' project several times,  I whole-heartedly agree the the instructable project with arduino controlled DSS would be much more suitable for the OP.
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