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1906  Using Arduino / Project Guidance / Re: Trouble aligning laser diodes on: March 07, 2013, 08:21:40 pm
Yeah but will it be enough?

You see what I mean about lever arm? It's like having a big dial vs a small dial to fine tune a radio. The diodes are small diameter so hard to adjust.

Another thought that might be better for staying aimed... put the diodes in ping-pong balls or the like and cut holes to hold them in stiff foam. Then turn the smooth ball to adjust aim and see if the foam holds it there. If the foam has some spring-back you might have to wiggle the ball as you aim or shave the hole a bit bigger. It's possible that square holes will do but I'd try round ones first.

That idea has the lever arm and a possible way to hold aim. Call it laser ball turrets.
 
1907  Using Arduino / Project Guidance / Re: Covering robot with metal on: March 07, 2013, 08:08:11 pm
Silver mylar?

Too bad you need so many sq ft. Joe Barker wrote a book on making models from soda and beer can metal.

Don't laugh too hard, can metal is plated to make the labels stand out. Some cans like Coors are highly shiny silver and some cans have a gold-color plating. The book covers recovering metal from the cans, removing the painted label and aspects of joins and all. The results just look fantastic. Check that bottom model;
http://www.fiddlersgreen.net/other/WSAM-Explained/sodacans/sodacans.htm

1908  Using Arduino / Project Guidance / Re: Record Changes in Height of Book Stack - Best Sensor? on: March 07, 2013, 07:23:16 pm
If the inside of the box is well illuminated then you only need detectors that the book spines would block or not. Maybe drill holes through the vertical slats and put the detectors in, but if the books are thin that would be a LOT of detectors needing to be wired. Good news is a bag of detectors might run 5 cents each.

I was looking at fiber optic cable, to feed the light from many to 1 phototransistor but wow, the cable I see costs more than detectors and wire!

You could try ultrasonic sensing from above the box. Check them on eBay, they're cheap.
http://www.ebay.com/itm/HC-SR04-Ultrasound-Wave-Detector-Range-Ultrasonic-Sensor-Distance-Module-/200896270284?pt=LH_DefaultDomain_0&hash=item2ec659cfcc
This looks the same as the ones I got from LC Tech. It's supposed to be good to 2mm but I didn't get that in quick testing. Getting it right should be a little problematic.

Quote
There is a 2" slit in front of the box which allows you to see the spine of the book.  In other words you can see that there are still books in the box without looking into it from the top.

That presents single detector possibilities but they would have to be positioned in front of the box.





1909  Using Arduino / Project Guidance / Re: Measuring the weight of a beehive on: March 07, 2013, 05:59:27 pm
I'm not sure that this will be good for beehives but if you have a mass that can move freely and an accurate accelerometer, especially at low G's, then if you apply a known force... F=MA.



1910  Using Arduino / Project Guidance / Re: Doppler Speed Radar on: March 07, 2013, 05:45:12 pm
Can you give it more power?

Also what you reflect from, smooth metal is best and for testing a corner reflector will send the most back. If you take a box and cut so there are 3 sides together making a corner then line the inside of that with smooth foil (try not to wrinkle) you will have a cheap corner reflector. Make it not small. Even if the reflector is not pointing directly at the source, the geometry will send the waves back. It works with light, it should work with radar.

Last is movement. The object must move relative to the radar either toward or away though sideways can be mixed in.
1911  Using Arduino / Sensors / Re: DS18B20 multiple sensors on: March 07, 2013, 04:03:35 pm
So long Troll.
1912  Using Arduino / Sensors / Re: Measure nightsky with TSL237 on: March 07, 2013, 02:30:18 pm
I am learning along here, i am trying out different float, unsigned longs etc... i have also got my "cheat-code" to work... i tried the freqmeasure.h and that worked like a charm...

don´t get me wrong here, i like to learn and i am listening to all of you! big thumbs up for you guys! So while i try to compile my "own" code i also trying librarys with examplecode...

just sharing what i tried yesterday, i also tried to add a button so i can choose when i want to take a reading.

Good move with the button.

When you use floating point constants like the 22 in
Code:
const float A = 22;

it's good to put in a decimal just to be sure, like how the UL goes on
Code:
const unsigned long U = 12345UL;

and usually people would write 22.0 instead of 22., I guess for easy reading.

Most of the time the compiler will get it right or it won't matter but it can gitcha and those bugs can be a real pain.

Keep on with the updates!



1913  Community / Bar Sport / Re: USPS out to kill hobby shipping on: March 07, 2013, 02:19:04 pm
For important parts it's well worth the extra. I guess you don't sell toys?  smiley-mr-green

1914  Using Arduino / Sensors / Re: DS18B20 multiple sensors on: March 07, 2013, 09:48:19 am
I hereby admit to being an ass to an asshole.

1915  Using Arduino / Sensors / Re: DS18B20 multiple sensors on: March 07, 2013, 07:56:56 am
Let me know when you've sobered up or your head gets down to regular size or they find the right meds for you, whatever.



1916  Using Arduino / Sensors / Re: DS18B20 multiple sensors on: March 07, 2013, 06:50:57 am
You can go through this forum and find many posts where I spell out 20 mA per pin and 200 mA total as recommended and not bright to exceed. My feeling is that the less you pull from the Arduino, the better.

But when someone says the SOS about me again and again despite me writing different, I might just pull their tail to see if they even notice and maybe got a hair across a sensitive spot.

Why would ATMEL say pulling 40 mA for extended periods MAY permanently damage the machine if that is no way true? Go climb up their butts. Maybe you will learn something you didn't expect.

As for me, I can see you do miss things and have your dearly held practices as I have mine but what is possible and can work doesn't care a bit for those.
1917  Using Arduino / Sensors / Re: Measure nightsky with TSL237 on: March 07, 2013, 06:05:53 am
Those frequencies are integer pulse per second Hz because of the 1000000 / microseconds part of the math.
They could as easily be pulse per msec by using 1000 / micros and give Hz to 3 places.
The other half of that trick is in placing a decimal point in the printout rather than resorting to floats.

Say I have 1234 pulse/msec in a variable named mFreq and I want to print Hz.
I print mFreq / 1000 and get the integer "1"
and then I print a decimal point.

Then I look at mFreq % 1000 which gives the remainder of mFreq / 1000.
If it's less than 100, I print a zero.
{
  If it's less than 10, I print another zero. Note I only check for < 10 if the value is < 100.
}
Then I print the remainder.

And yes, it can be rounded up or down but you best do that when calculating what you will display.

Remember that display is for looks. Don't let looks dictate substance, they should only reflect it.
On a full-blown PC, I'd go with doubles but with Arduino I go with what works best and happens to be fastest as well. And this time I didn't need to use long-long's for intermediate steps!   

Let me know if you need more. Maybe Rob or someone else won't get there first. My posts are just my attempts to help.

1918  Using Arduino / Sensors / Re: DS18B20 multiple sensors on: March 06, 2013, 09:28:39 pm
ATMEL EEPROM datasheets don't list the ATMega 328P, do they? But they say bits so you just hang tight to that and let denial take care of the rest.

The ATMEL datasheet for the ATMegas including the 328P says:
Quote
ATMEL: – 256/512/512/1KBytes EEPROM
Quote
ATMEL: 8.4 EEPROM Data Memory
The ATmega48A/PA/88A/PA/168A/PA/328/P contains 256/512/512/1Kbytes of data EEPROM memory. It is organized as a separate data space, in which single bytes can be read and written.

That's BYTES there, not bits, as in ATMEL says the 328P in the UNO has 1k BYTES of EEPROM.

What does Arduino say?
Quote
Arduino: EEPROM   1 KB (ATmega328)

I won't bother quoting the forum but a lot of people writing and reading UNO EEPROM's keep saying there's 1k bytes. Nobody is saying that after byte 127 they ran out.

I didn't tell some poor user the UNO has 1k bytes of EEPROM when there's 1k bits. That's because there really is 1k bytes EEPROM in the UNO.

1919  Community / Bar Sport / Re: Your latest purchase on: March 06, 2013, 08:42:40 pm
Just got a partial shipment on what may be my last order from DX (DealeXtreme).
Got 50 40-pin header strips (steel, not brass pins), 10 keychain SD-micro/USB adapters and 3 IR signal receivers and a bag of jumpers. Still waiting on 10 2 mW laser modules (because at 45 cents ea, I'll make a use), 10 snap-in RJ-11 modular jacks, and 2 female-female 40 cm DuPont cables.

Well, I might order disc batteries from them but I can't say about that either.
1920  Using Arduino / Project Guidance / Re: Trouble aligning laser diodes on: March 06, 2013, 08:23:08 pm
The white plastic stick you made to hold the leds.

You could try to angle adjustment screws in from the sides so the screws are 90 degrees apart. The screws would adjust along one diagonal each instead of horizontal and vertical.

OTOH you could try using shim wedges in the holes that hold the lasers. That would be thin tapers going through the holes, how far any one is in or out would change the taper thickness between the side of the hole and the laser with a good bit of in and out making small change in aim.

Can you print individual led holders with a finger length stick out the back? Then that stick becomes a lever long-arm you can adjust easier than the little body of the laser. But how you mount and hold that I just dunno.





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