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10756  Using Arduino / General Electronics / Re: Can I use stained glass flux for electronics? on: February 17, 2011, 02:48:38 pm
I would suspect it comes down to the chemistry used in the flux. My limited knowledge of the subject is that some fluxes are acid based and some rosin based, where electronic applications always stressed to not use acid based flux.

10757  Using Arduino / Project Guidance / Re: Make a permanent project on: February 17, 2011, 01:27:32 pm
How can a project be made permanent? Instead of investing an entire Arduino into the project, are there any ways to separate and utilize the active components with functioning code?

It's pretty simple and straight forward. Do a search on "Arduino standalone" and you should get more then enough examples on how to proceed.

10758  Using Arduino / Motors, Mechanics, and Power / Re: Pwm output is high on bootup? on: February 17, 2011, 01:07:26 pm
probably not reseting pins to input mode.
No that happens automatically as a result of the reset pin being hit. It is a hardware thing.

I'm not so sure, the Uno/Optiboot 'features' and the new 8u2 usb converter chip sure made for a rather rocky introduction to the latest board offerings from Arduino, with more bugs then any other new board offerings I can recall. And also requiring two IDE releases in very short order.

 In hind site they would probably been better off just introducing the 8u2 feature and put off changing from their more proven bootloader code. That or they need a better beta process before rushing new boards to market.

My money 2 cents is that this symptom uncovered in this posting will be at least related to the new bootloader if not directly caused by it. No proof, just shooting from the hip.  smiley-wink
10759  Using Arduino / Motors, Mechanics, and Power / Re: Issues Controlling a Digital Servo on: February 17, 2011, 05:51:12 am
I've also tried the Arduino sample servo sweep code. In this case the servo moves to 0, then rotates about 120 degrees, then stops and makes the high pitched buzz with no further movement.

It's probably hitting a mechanical stop. Not all servo are designed to move 180 degrees, 120 degrees is a common range for R/C servos. Send a 1000usec and then a 2000 usec pulse to determine the designed normal travel range. Most servos will have a little 'over-travel' above and below 1000 and 2000 respectively, but how much over-travel varies from servo to servo. Don't force it to a position where it's buzzing continuously, it's not showing you love when it does that.

10760  Community / Bar Sport / Re: What else offer an Arduino MEGA beside the big amount of ports? on: February 17, 2011, 05:40:43 am
You didn't state if Mega or Mega2560 but other then memory size those two are equal. You get besides more I/O pins you get 4 hardware serial ports, five user interrupt pins, more timers.

It really depends on the project scope you are going to work with. I still like arduino board that use socketed dip chip 328 processors because you can develop your program on the arduino development board, and then pop the chip out and wire in your project circuit as a standalone microcontroller with just a couple of support components and buy a $6 replacement 328 chip and you are ready to develop your next project. Any of the SMD packaged processors (Uno or mega or nano boards) aren't as DIY friendly for that kind of development cycle.

10761  Using Arduino / Programming Questions / Re: Stopping signal output to servo when input unchanging. on: February 17, 2011, 05:08:01 am
Instead of debating the subject with too many unknowns, just give it a try to see how it will actually work. Servos are not that expensive if things don't work out.

That is a $ 60 servo he is playing with there  smiley-money  I certainly would have second thoughts of applying 10vdc to a servo designed to work off 4 series AA cells.
10762  Using Arduino / Sensors / Re: ADC reading changes when digital pins are HIGH on: February 17, 2011, 04:15:47 am
I think it's just the nature of the beast. Where there is digital and and analog signals sharing the same IC die, board ground plane, and power traces your going to see a certain amount of noise, jitter, variation, whatever one chooses to call a differnce between theoretical conversion vs actual conversion. The 10 bit +/- 2 LSB of total accuracy is a very loose spec that AVR allows themselves. That says you can't rely on better then +/- 3 counts overall accuracy worst case.

 If you desire or need instrumentation quality A/D performance then you should look at purpose build dedicated analog front end and A/D converter chips placed on well designed PCB with proper support components. The AVR built in A/D pins are a really cool feature and very very useful, but expectations need to match reality. There are things one can do to smooth out conversion performance, like external RC filtering or software averaging over multiple sampling.

10763  Using Arduino / Motors, Mechanics, and Power / Re: Protecting Arduino connected to a power supply? on: February 17, 2011, 12:40:55 am
Which servos are you using?
Not all hobby servos can handle 12v.  Most of mine let the magic smoke out at that voltage.
Many of the newer ones can handle it though.

Can you give us a link to some of those 'newer ones' that can handle +12vdc?

10764  Using Arduino / Programming Questions / Re: Stopping signal output to servo when input unchanging. on: February 16, 2011, 11:21:01 pm
I talked to Hitec and they said it would greatly reduce the life of the servo but if I turned it off while holding a position it probably would not be detrimental so long as it is not used continuously at that voltage. Having the voltage across the servo doesn't matter though I think. So long as it has no control it is not doing any work and thus not generating any heat.

That's not my take on it at all. As long as you have +10 vdc applied to the servo's power pin you are stressing the heck out of it and I would never recommend running a servo at above it's rated voltage range, most spec 4.8vdc to 6vdc. The fact that the servo is detached with no control signal just means the motor won't be drawing current, but that has nothing to do with voltage stress on all the semiconductors used inside the servo. Running components above their maximum recommended specification is never a good idea. If you need a stronger faster servo then buy or build one. At least that's my advice and worth what you are paying for it.  smiley-wink

10765  Using Arduino / Project Guidance / Re: Spray can and Arduino on: February 16, 2011, 11:12:16 pm
Just buy a mean dog. No legal problem if your dog mauls a burglar if it happens inside your home.

10766  Using Arduino / Project Guidance / Re: Voltage/Current control via PWM? on: February 16, 2011, 11:07:51 pm
I hope this clears things up.  It's difficult to convey an idea without actually spilling the beans.  But I think you can get the point.  Actual values do not matter here in this forum.  I'm mainly looking for methods.

I'm afraid you have given us not enough to work with. A schematic drawing would be a nice starting point, showing the wiring and what and where you want to measure and/or control. You don't have to name the mystery parts, just draw their equivalent electrical properties.

I suspect that if this was such a great secret project that the techinical players could better describe the basic function they are requiring from the arduino. Saying it will sometimes be turned on and other times turned off is probably true of 90% of the Arduino projects ever built.  smiley-wink
10767  Community / Bar Sport / Re: My first and probably last arduino project on: February 16, 2011, 10:53:57 pm
Only then did I notice that there was a 100 megawatt 50 gazillion lumens street light that shined all over that viewing area.

That's funny.

Is now, back then, not so much. I did spend a couple of weeks trying to figure out if I could make the street lamp turn off. Like most street lights it had a sensor so it didn't waste power trying to compete with the sun, so I tried aiming flash lights, spot lights, etc to trick the light sensor, but to no success. This was before affordable lasers so maybe that would have worked? I really really really considered just shooting the damn thing out, but I guess my conscience got the better of that idea. Plus with my luck they would just repair it in record time.

10768  Using Arduino / Programming Questions / Re: Different Tabs on: February 16, 2011, 10:46:53 pm
Lefty, if you write code in a separate .pde file, you need not worry anything as all .pde files are concatenated before compile so it the same as writing all those lines of code in one file, which is not very visually appealing.

If you put anything in .c or .cpp files, those files are compiled separately and later linked together. In order for the main .pde to use any functions (old fashion C or C++), you need declarations of these functions in your main .pde file.

I'm writing a blog post on this issue. It's mostly done but I'm still typing the last part.

I look forward to reading again when completed. Please repost when your done.

10769  Using Arduino / Project Guidance / Re: Measure time for a tank to empty by weight on: February 16, 2011, 10:17:17 pm
@Graynomad I wish I was < 25 smiley

Calculating flow shouldn't be a problem

Get a reading every 5 minutes
Old reading - New reading = flow in 5 minutes
(Full reading - New reading)  / flow X 5 minutes = time remaining

Ah, the old rate of change calculation. That would be pretty simple. They used that in a refinery I worked in, as they already had a accurate level measurement avalible, so creating alarms on changing levels when the tank was not suppose to be opened to anything was easy, and rate of change gave the operators an idea of when they might have to leave to drive to the tank to shut it in after a large product transaction for the tank. A RTC chip would help make it easy, however just tracking via millis() time stamps should work as well.

10770  Community / Bar Sport / Re: My first and probably last arduino project on: February 16, 2011, 10:11:26 pm
Sound like a telescope project I got involved with many decades ago. I read and researched for a couple of years, finally selected a 8" reflector design and got to buying parts and such. Finally got it all working and took it out the first night to my only available southern viewing site in my backyard. Only then did I notice that there was a 100 megawatt 50 gazillion lumens street light that shined all over that viewing area. The scope worked fine, but my eyes were never able to really dilate to full open enough to really utilize the power of the scope. Oh well I did enjoy learning about telescopes and the project was a technical success, in not a practical success. I learned something from that lesson, not sure what it was but I learned something.  smiley-grin

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