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676  Using Arduino / General Electronics / Re: soil moisture circuit on: June 22, 2012, 09:34:56 am
Rather than using software to create diagrams, go old school and use pencil and paper, then just scan or take a digital photo...

The interesting thing about the sparkfun approach is that it shows how to perform the function without using the 555, since the arduino can provide the pulsed dc.  They have schematic and source code available, so you could use that to learn how to implement circuit yourself.

While the comments by Docedian are valid, you have to decide if you are doing this for the outcome (you just want the measurements) or the process (you want to learn how to do this yourself).  If the former, you would be better off purchasing commercial sensors since you will not be able to build something for less that would last and perform well.  If the latter, than while hints as to what will fail and why are useful, making mistakes yourself and learning from them are key to understanding.  So use pulsed DC and then watch and see how the signal degrades over time and understand why...  If the signal degrades quickly, then of course the technique isn't very useable, but if the signal remains of a useful quality for months, then maybe replacing the probe becomes more reasonable.  And as time goes by, you can learn how to implement better techniques.

Just decide if the journey or the destination are more important!

677  Using Arduino / Project Guidance / Re: my first project problems on: June 22, 2012, 07:18:06 am
It sounds like you have made a good start, in that you have gotten each component of your project to work separately. I suggest you try combining two functions, and then testing.  For instance, combine the two ldr's with steering changes; something like:

   if (ldr1 < ldr2) then steer left
   else (ldr1 > ldr2) then steer right
   else go straight

Get that working, then work on your detection of an obstacle.  You will either need an additional sensor to detect that the car has hit an obstruction, or if the motor shield has a current sensor, you can use that to determine that the motors have stalled.  The ldr's will not really be able to detect an obstacle.  If you run into problems, simply post your sketch that your having a problem with and give a good description of the error/issue your having and someone will help!
678  Using Arduino / General Electronics / Re: soil moisture circuit on: June 21, 2012, 07:21:37 pm
An Analog pin can measure (if defined as analog in the definitions in the sketch... any voltage between 4.88 mV to 5V... it is a common technique to "Average" a pulse train  to make an analog voltage that represents the "Average" DC value of said pulse train or if you will stream or input. for example look at "analogWrite" A PWM signal "Averaged" to an analog value. There are several issues with the schematic as drawn. Pin 4 (Reset) as mentioned must be tied high and Pin 5(Control) should go to ground through a 10 nF capacitor although the schematic doesn't do that... the data sheets ALL mention that pin and it's uses. Soil moisture Must be measured with an AC signal to prevent polarization of the electrodes. Dc will appear to work... but what of the composition of the soil and what else is there that is conductive as well, are the measurements going to reflect the moisture of the soil or the other conductive chemicals that might be present as well. I spent 5 years designing and manufacturing soil conductivity measurement devices. Successfully. The main issue is that the implementation as drawn will not work and the OP apparently doesn't have the knowledge yet to make it right so let's concentrate on fixing that first.  randomworth... first why would you say that you don't need a specific part? what is going to take it's place? usually a designer specifies parts for a reason, do you know more that the other person about his apparently working device? My point is not to embarrass you but rather to get you to focus on a set of specifications first... how is the device to be used? as a plug-in to your Arduino? A stand alone device, is it for you or someone else and how is it going to be used? are the electrodes going to be permanently in the soil or are you going to build a probe. No project work better that it's plan and you don't seem to have formulated that yet. So lets begin by Formalizing what it is that you want to do and how the device must operate. Do you want a relative moisture meter, you can buy one for $5 or $6 dollars. Do you want an accurate one that will return conductivity in Millisiemens (can't remember the spelling) and if so over what range?
You need to supply some more information besides an incorrect copy of an incorrect drawing.


The specific part he didn't used was a dc regulator ic, which droped the supply voltage to 3v, since he is using the 3.3v supply from the mega he doesn't need that to implement that circuit.  Other than the one missing connection his circuit was a valid implementation of the reference circuit he mentioned.  I have no idea if that circuit would work for this purpose; however, the reference text for that circuit was clearly wrong when it claimed that circuit was producing an AC resistance measurement.
679  Using Arduino / Microcontrollers / Re: how to read multiple analog temperature snesors LM35 ? on: June 21, 2012, 07:17:10 pm
Yes, just include the sensor being read in addition to the sensors value when it is being sent to the host computer.

680  Using Arduino / Microcontrollers / Re: problem to burn bootloader using usbtinyisp on: June 21, 2012, 07:15:38 pm
Does your programmer supply power through the ISP connector to the device being programmerd?  My AVRISP MKII does not, and I get similar message unless I also wire up power to the device in addition to the ISP connections.
681  Using Arduino / Project Guidance / Re: Gboard battery with solar setup on: June 21, 2012, 02:34:59 pm
DC to DC converter for moderate to low current demands...  Standard 12V solar charger and deep cycle batteries for higher level demands.
682  Using Arduino / General Electronics / Re: soil moisture circuit on: June 21, 2012, 01:49:58 pm
In comparing your circuit to, which I believe you used as inspiration there is at least one discrepancy, pin 4 on the 555 should be connected to 3.3V

Also, since that circuit is designed to provide a frequency output, not an analog signal, you really shouldn't try reading it using an analog pin, which will give you only two readings; 3.3v and 0 depending upon where in the pulse it measures.  You need to hook this to a digital pin and use a frequency measurement technique (

Also the description for that circuit is incorrect when it says that the technique is using AC current to measure the resistance; it is using pulsed DC, which is not the same.  Pulsed DC, like AC, has a frequency, but the direction of current flow is constance, where with an AC signal, the direction of current flow changes.
683  Using Arduino / Microcontrollers / Re: ATtiny84 and TinyDebugSerial shows garbled text.... on: June 21, 2012, 01:10:02 pm
CodingBadly's tiny core has no problem providing serial output on the tiny84--at least for me at 1MHz and 8MHz using the internal clock and a 38400 baud rate.  The trick is using the correct pin.  On Speeds less than or equal to 8MHz use pin 2, at 16MHz use pin 13.  Since it is bit banged serial, I don't think it will work at speeds other than those three.
684  Development / Other Software Development / Re: Beta testers needed for a new library that generates true random numbers on: June 21, 2012, 07:51:51 am
Here are some additional test results:

IDTesterDeviceChipDate CodeTypeSample SizeEntropyChi squareP-valueMeanS.C.C.Comments
037wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP102,4127.998406225.980.9045127.14730.000618
038wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP100,3687.998131260.480.3935127.4403-0.004133
039wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP101,9647.998389227.510.8914127.0540-0.004832
040wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP236,1367.999246247.630.6178127.3000-0.002023
041wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP100,1447.998202249.550.5846127.80170.000526
042wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP107,0927.998095282.900.1108127.42410.001396
043wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY85-20PU1211DIP100,1687.998309234.680.8146127.59220.002843
044J. ChristensenArduino UNO SMD EditionATmega328P-MU1034SMD1,000,0007.999809264.470.3286127.3932-0.000010
045J. ChristensenBreadboard Arduino close, 16MHz xtalATmega328P-PU1107DIP1,000,0007.999792289.050.0702127.50880.000577
046wandrsonBreadboard 1284p, 16mhz xtalATTINY1284P-PU1211DIP446,9727.999577262.650.3575127.4290-0.002572
047wandrsonBreadboard 1284p, 8mhz xtalATTINY1284P-PU1211DIP109,7407.998350251.610.5483127.52610.001790
048wandrsonBreadboard 1284p, 8mhz xtalATTINY1284P-PU1211DIP318,4327.999402264.350.3305127.55980.001933
049wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY84-20PU1010DIP278,9607.999355248.840.5969127.8017-0.003964
050wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY84-20PU1010DIP100,2887.998213249.050.5933127.5756-0.003266
051wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY84-20PU1010DIP100,0207.998360226.460.9009127.3991-0.002293
052wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY84-20PU1010DIP102,9167.998466218.490.9527127.3037-0.002528
053wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY84-20PU1010DIP265,4207.999419213.390.9728127.61360.000817
054Coding BadlyArduino UNO R2ATMEGA328P-PU1107DIP839,9887.999778257.950.4367127.3391-0.003102
055wandrsonBreadboard 1284p, 8mhz xtalATTINY1284P-PU1211DIP649,7287.999697273.190.2071127.4459-0.001684
056wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY84-20PU1010DIP102,8607.998113269.980.2483127.55590.005196
057wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY84-20PU1010DIP96,0687.997948274.550.1911127.45900.005131
058wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY84-20PU1010DIP101,1647.998136262.130.3661127.0534-0.004649
059wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY45-20PU1211DIP284,0727.999377245.090.6610127.3208-0.000006
060wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY45-20PU1211DIP100,0727.998263240.500.7341127.3423-0.003373
061wandrsonBreadboard tiny, 16mhz (internal oscillator)ATTINY45-20PU1211DIP110,6447.998224272.660.2136127.47350.002846
062wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY45-20PU1211DIP100,9127.998196252.700.5289127.34670.008878
063wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY45-20PU1211DIP100,1647.998027273.660.2016127.21110.002015
064wandrsonBreadboard tiny, 16mhz (internal oscillator)ATTINY45-20PU1211DIP214,7607.999182243.370.6891127.4248-0.005771
065wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY45-20PU1211DIP103,6567.998399229.730.8704127.4767-0.003893
066wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY45-20PU1211DIP118,6767.998584232.000.8463127.3653-0.008254
067wandrsonBreadboard tiny, 16mhz (internal oscillator)ATTINY45-20PU1211DIP107,9207.998366244.520.6704127.2434-0.007688
068wandrsonBreadboard tiny, 1mhz (internal oscillator)ATTINY45-20PU1211DIP101,7167.998237247.820.6147127.2760-0.000026
069wandrsonBreadboard tiny, 8mhz (internal oscillator)ATTINY45-20PU1211DIP231,7407.999281230.800.8594127.5449-0.000518
070wandrsonBreadboard tiny, 16mhz (internal oscillator)ATTINY45-20PU1211DIP123,8207.998312289.800.0662126.9300-0.003889
071P. StoffregenTeensy2  5v, 16MHzMEGA32U4-AU0945SMD383,3807.999503264.980.3208127.65700.001401
072Elvind TrielArduino DuemilanoveATMEGA328P-PU0948DIP1,226,2567.999859239.460.7495127.6417-0.000672

All of the above tests were performed on different chips. No repeated tests on the same chip, unless otherwise noted. Since test number 018 failed so spectacularly, I retested that same chip in test number 022. Tests 014 - 022, 025-026, 034-043, 049-053, and 056-070  were performed using from Test 027, 032, 046-048, and 055 were performed using Mighty 1284P core files.
685  Using Arduino / Project Guidance / Re: Gboard battery with solar setup on: June 21, 2012, 07:32:20 am
Adafruit has a couple of products that may help:
686  Using Arduino / Project Guidance / Re: Camera control on: June 21, 2012, 06:24:06 am

These are just a few of the articles found that may help,or.r_gc.r_pw.r_qf.,cf.osb&fp=dd77c1d95ca3fbd9&biw=1855&bih=961
687  Using Arduino / Programming Questions / Re: Parallel I/O - e.g reading or writing a whole byte, not one pin at a time on: June 21, 2012, 06:08:12 am
Datasheet ->  "This is the bible for development with the 168 chips"  Similiar documents are available for the other chips used in Arduino's

MLF -> Micro lead frame package

ADC6&7 are available in any of the 32-pin variants of the 168.
688  Using Arduino / Programming Questions / Re: Parallel I/O - e.g reading or writing a whole byte, not one pin at a time on: June 20, 2012, 07:06:17 pm
Each of the ports have a variable defined in c for such activity; PORTA, PORTB, ...
Excellent.  Thanks.  I take it I can still configure them with pinMode()?

I don't see anything about that in the language reference either.  Is there a list of predefined variables somewhere?

You can still configure them with pinMode(); however, there is also a variable for each port that can allow you to set pin modes for the entire port at one time; DDRA, DDRB, etc...

Note that these port variables work MUCH faster than the Arduino functions...
689  Using Arduino / Programming Questions / Re: Parallel I/O - e.g reading or writing a whole byte, not one pin at a time on: June 20, 2012, 07:04:35 pm
The functions are part of AVR-LIBC which is what the Arduino IDE uses at its base.  The relevant section of that manual is
690  Using Arduino / Installation & Troubleshooting / Re: Program Upload on: June 20, 2012, 07:02:24 pm
What driver is it saying is being used when you verify the port in Device Manager?
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