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16  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?
17  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.
18  Using Arduino / Project Guidance / Re: How to make a waveform generator with frequency of 20hz-20Mhz on: March 31, 2014, 08:47:29 am
Ain't gonna happen with an Arduino.....
Go to eBay, but a couple of MAX038 chips and a bunch of REALLY wideband Op-Amps.
19  Using Arduino / Project Guidance / Re: Wireless LED on: March 25, 2014, 10:42:52 am
I've had better luck sending multiple messages with a different header (which is particular to the intended recvr) in each message.  the 433MHz modules i've used ar AM and therefore subject to a lot of noise and backend arduinos don't always get the entire message packet.  I've had a lot better luck using Nordic modules.
20  Using Arduino / Project Guidance / Re: wireless video transmitter connection with arduino? on: March 24, 2014, 02:29:59 pm
Actually, an arduino is more than capable of controlling the camera (turn on/off and settings), but why? The camera system's transmitter/receiver setup already provides this through the video receiver.....
No, an arduino can not do video processing, but that wasn't the question.
21  Using Arduino / Project Guidance / Re: em-406a help on: March 24, 2014, 02:15:36 pm
Aw man, they deleted the tutorial...... mega-bummer... (I think they are upgrading to a new recvr with more chan.s, so the 406 will probablly be obsoleted soon).

Checkout TinyGPS in the playground. 
22  Using Arduino / Project Guidance / Re: em-406a help on: March 21, 2014, 09:43:15 am
Works for me.
Go to
search for em-406a
23  Using Arduino / Project Guidance / Re: nrf24l01 new project idea on: March 21, 2014, 09:35:39 am
If you are somehow thinking of timing RF pulses through the NRF, you are going to need a faster boat.....
24  Using Arduino / Networking, Protocols, and Devices / Re: I2C Master controlling multiple devices on: March 18, 2014, 02:46:28 pm
Well,,, at least he didn't call you a bumbling dunderhead who has no idea how to post a question.....
Oh,,, well, he sorta did, didn't he.....

Maybe you should 1) post an actual question, or 2) change your thread title to "Mommy, Mommy, look what I did!", and 3) stop calling respected members foul names, and 4) YOU go some where else.
25  Using Arduino / Project Guidance / Re: Agriculture - Finding Area of a column of falling particles (grain) on: March 18, 2014, 11:42:59 am
You're still brainstorming an unknown problem.
When you make assumptions about issues, whithout sufficient information, Fate calls up a guy names 'Murphy'.

26  Using Arduino / Project Guidance / Re: Agriculture - Finding Area of a column of falling particles (grain) on: March 18, 2014, 10:02:30 am
There you go being logical again....

I was wondering if I was the only one who thought this has a lot of holes in it...
27  Using Arduino / Project Guidance / Re: How to Generate Square Wave in Bursts with Variable Amplitude on: March 18, 2014, 09:59:34 am
or an OP-Amp with a digi-pot in the feedback loop, controlled by the arduino,, or a staircase generator to provide stepping offset to the digital outout, or,,,
28  Using Arduino / Project Guidance / Re: em-406a help on: March 18, 2014, 09:56:17 am
Sorry for the late reply.  I thought I got this in yesterday, but I see no entry for it....
Oh, well...

Go to the 'SparkFun' website and look up the EM-406A (
Start with the NMEA Reference Manual, under 'Documents', then look at Simpson's "GPS TUTORIAL".
That will tell you how to select which sentences you want from the GPS module's message burst.  Modify that suit the needs of your project.

Good luck and have fun.
29  Using Arduino / Project Guidance / Re: Object Tracking for a Camera on: March 13, 2014, 11:53:37 am
Not actually,,,,
Depending upon what material is between emitter and detector, wavelength of the IR, and power emitted,,,,,  I have been able to detect IR emitter in a shirt pocket from 5 feet (do not have any idea what the max distance would be, did not test it) and UVb worked much better.  However, is moot point.  No way it'll work over 150 feet....... (sighs and wimpers)
30  Using Arduino / Project Guidance / Re: Project guidance for code-based locker opener on: March 13, 2014, 11:39:16 am
not REALLY relevant, but how many lockers, how many kids?  (and what kind of budget, is this just proof of concept?)

It shouldn't be a big deal to get the building facility folks to run a low voltage line from the classroom (where you have A/C outlet and place the supply) to the lockers.  Although 'transmission' of D/C power induces a lot of losses, it shouldn't be much of a problem in this case (and you can revert to low voltage A/C to the lockers and A/C to D/C convert at the lockers; bridge rectifier,  filter caps, and linear regulator).

But it is your call, it's your project/application.  JUST DON"T RELY ON 9V BRICK BATTERIES.
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