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46  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)?
47  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.
48  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.
49  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.
50  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????
51  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.
52  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.
53  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!
54  Using Arduino / General Electronics / Re: Switching 220V light bulbs on: April 08, 2014, 09:32:14 am
Can you spell TRIAC?
55  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.
56  Using Arduino / Project Guidance / Re: Best way to track a flying object/Indoor object tracking. on: April 03, 2014, 10:19:05 am
I remember something about a group using Wii controllers to track IR emitters.  Try Googling 'WiiMote'.
57  Using Arduino / Project Guidance / Re: Putting a display on MAX038 on: April 02, 2014, 12:41:14 pm
MAX038 is an analog waveform generator chip.  You won't be putting a display on it.
You might build a waveform generator project (CIRCUIT) arround the MAX038.
You'll need to buffer the outputs with wideband amps to avoid loading the MAX038.
You can use digital signals, from an arduino, to control the type of wave generated.
you might be able to use digi-pots, controlled by anarduino to set frequency, offset, duty cycle...
you can tap the sync output of the circuit with a frequency meter based upon another arduino (or a PIC) to drive a display to show the output frequency of the circuit.

It gets to be a very complicated set of sub-projects.  Do-able, but intense.....
You might not yet have the expertise/experience to accomplish it all.  But, if you stay with it, do a lot of research, you can get there.
58  Using Arduino / Project Guidance / Re: How to make a waveform generator with frequency of 20hz-20Mhz on: March 31, 2014, 09:29:12 am
Not compared to a MAX038........ Ha, ha, ha,,,,, (almost the same,last time I was able to find a supplier of MAX038's).
59  Using Arduino / Project Guidance / Re: How to make a waveform generator with frequency of 20hz-20Mhz on: March 31, 2014, 09:23:12 am
We are all obsolete, but we are still here and, mostly, still work.

Thanks Bill.

A 555? really? MHz output? 

John Bigbooty, where is my overthruster?
60  Using Arduino / Project Guidance / Re: nRF24L01 project help on: March 31, 2014, 09:20:43 am
I think that they might be trying to say that you are asking how to drive a nail with a screwdriver.  Yes, nails can be driven (yes, doppler shift in transmitted vs received wavelengths can be detected), but not with a screwdrived (or an NRF24l01, and an arduino...). 

Study up on HB100 Doppler motion sensor (not really what you want, but will demonstrate doppler shift).
you will need to understand multi-stage amplification and wave shaping via op-amp.s and how to display the demonstrated frequency shift.  The HB100 will detect movement by measuring doppler shift in xmit vs rcv RF signal via internal circuitry (and size/distance by maginitude of returned signal, but not very accurately or with much repeatability).  The module, unfortunately, outputs a very low level sine signal.  You amplify that output signal (in multiple stages to reduce noise artifacts), overdrive to clip the waveform, and provide an offset to make it a non-zero-crossing square wave, then present that signal to the arduino for something like PULSEIN...... since the output frequency range of the HB100 module sisomething less than 3IKHz, you could simplly connect the amplified output to a speaker and use the audio shift to demonstrate the doppler effect.

However, as has been stated multiple times, give up on the idea of using the NRF24L01.

By the way, I have outlined a possible solution to whatever your project really is, and I have about one twentyith the technical expertise of the guys who have been telling you the Nordic radio will not work for this.
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