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1846  Using Arduino / Programming Questions / How would I Set and Clear [Solved] on: September 01, 2012, 05:12:08 am
I fixed it...
I just threw it away as a bad receiver

Doc
1847  Using Arduino / General Electronics / Re: Speaker or line-out jack... on: August 31, 2012, 04:46:39 pm
Quick one word answer NO. you have 4 wires that need to go to the jack... not counting the ground. Line out, the unswitched output and the connection to the volume controls that you are switching with the jack. You could of course use a DPDT mini toggle switch. That would take care of the audio switching necessary... But it won't happen when you insert the plug... You could use the mono jack to activate a relay... but that meqans that if you loose the plug (Shorting plug to "switch on the relay...) But If you lost it... No Switch. Here is an inexpensive one from a place I spend money at (Lots of Money, they have Lots of inexpensive Goodies)
http://www.electrodragon.com/?product=3f07-double-sound-channel-3-5-audio-jack... The Part is PCB mounted only But it is $0.21... Most all of what they sell is in that class.

Doc
1848  Using Arduino / General Electronics / Re: "perfect" logic level shifting on: August 31, 2012, 04:18:04 pm
Use the Sparkfun circuit... and use 2N7000's I've done it twice and BOTH worked perfectly. The 2N7000's can plug into an IC socket... Too. Not SMD. CHEAP and easy to do. See the NXP10441 App Note that I included with this post. It gooes through... with great detail what is necesssary. The IC's (the true Bi-Directional level shifters) are similar to the App note concept, just in a single package, SMD and difficult to deal with. The devices were designed to eliminate the necessity of placing all the parts required for the Mosfet idea. A GREAT idea for reduced production cost's BUT hardly an initial requirement here. When your device is debugged and you haave your first order for 1K pieces... Then BY ALL means use the IC's. The Logic gates, transmission gates (CD4066) and other ideas either are one way or they aren't capable of any current (@ 3V3 a CD4066 has about 500 ohms of series resistance... with that and a few hundred pF of board capacity... you have a great first order low pass filter... Not so great for I2C or SPI... As those signal bus's operate at a speed high enough to be crippled by a filter with a 100 KHz corner frequency. I modeled both the Mosfet and a Bi-Polar variant in MultiSim 11 before I choose the 2N700'0s. Both simulated perfectly and the Mosfet version looked real good when I looked at it with my O'scope... In Circuit between a BMP085 and an Uno Nice "Crispy Sharp" edges on both clock and data. It only takes 2 Mosfets (in TO-92 packages and the same pin lineup as a 2N3904 except    gate for base, source for emitter and drain for collector) because you will already have or need the 3V3 and 5V pull-ups... So just 2 cheap parts. I've got about 20 of them... PM me If I can Help. AND READ the App note... Too.
{Edit Doc}

Doc
1849  Using Arduino / General Electronics / Re: Square Wave Generator Problem on: August 31, 2012, 03:39:14 pm
am LM324 is a difficult device to get a good square wave out of. This is caused by it's poor high frequency response. You can built a relaxation oscillator much easier with a 555 oscillator/timer chip. A 7555 is a 5V Cmos version that might work as well and they are sold at Radio Shack. There are two devices that might work better for you one is an Exar XR2206 (Sold as a Kit by Jameco) and the other is an improved... XR2206 called a Maxim MAX038. Both will work from several 10ths of a Hz to 500 KHz or more (Decade value capacitors and a rotary switch). Both chips are called Function Generator IC's and both will produce fairly low distortion Sine Square and Triangle waveforms.

Doc
1850  Using Arduino / General Electronics / Re: Speaker or line-out jack... on: August 31, 2012, 03:30:24 pm
S "switch Jack", as has been pointed out already. The Idea about the IC is no good... that device only mutes the speakers when headphones are plugged in, albeit without a switch jack... it was apparent that he didn't understand your Post. Use the switch jack to switch off the audio to the power amp when the line output is in use. If you place the jack before the Vol control then your line out won't be affected by the volume setting which is normal for a line out. In fact that's why it's called "Line Out".

Doc
1851  Using Arduino / General Electronics / Re: Turbo charger controller advice. on: August 31, 2012, 03:23:17 pm
I think Martin is exactly right, Preconditioning (filtering and CLAMPING the 12V line can't cause anything to "not work" So at least a 100uHy Choke a .001 to a .01 Farad Cap (on the cold side of the choke) and a Tranzorb at a minimum... might well clean up what is a potential "noise receiver" and turn it into a workable ignition control or sensor network. You have a source follower for the RPM data input... try a 1nF cap to ground from the source. All of the noise "Power" in a square wave is contained in the leading edge... If you slightly slow the rise time you eliminate most of it's noise producing potential because most of the high frequency information (noise) is in the leading edge.

Doc
1852  Using Arduino / General Electronics / Re: Solenoid doesn't work on: August 31, 2012, 12:41:32 pm
One more "small" hint might well be to shorten the leads on the components used on a bread-board... Doing so will make it much easier to make secure and "Short-circuit" proof connections. What I do is keep a basic set of components that I only use for breadboarding. Doing so prevents "accidental" loss of sensitive components. It also makes it MUCH easier to see what you really have wired on the breadboard. One More thing... Neatness counts too, as far as making accurate wiring and being able to draw what you really have, in preparation for your "Final PCB"

Doc
1853  Using Arduino / General Electronics / Re: 3.3v to 5V logic level shifter using transistors on: August 30, 2012, 10:41:47 pm
The major failing in Any (almost) IC level shifter is that it isn't Bi-Directional, Most data bus are bidirectional. There are 8 connections to use both Mosfets and at least that many pins on an IC. Don't forget you must deal with the inputs to Any unused gates. The possible reason \why the 4066/4016 failed... @ 5V  it has a typical on resistance of 400 ohms @ 5V Vcc. at lower voltages it gets worse... The TI data sheet I enclosed isn't the same as the RCA as the chip is characterized and Specified to 3V, The Resistance would almost double, If the curves for 5, 10 and 15 volts hold true.
One last point about the Mosfet Level Shifters... all the parts would plug into an 8Pin IC socket... with 2 extra pins left free. the pull-ups are required with either solution so they don't count.

Doc
1854  Using Arduino / General Electronics / Re: Why use 2 decoupling capacitors? on: August 30, 2012, 10:22:50 pm
In my few years at the Electronics... I don't believe I have Ever seen a board fail due to too many Bypasses,, But I've seen a bunch that failed because of too few and more than a few of mine suffered that initial condition.
Having said that I utterly fail to find any sense in deciding how few you can get away with using in a design. The parts cost much less than the possible time figuring out why it doesn't behave "exactly" the way you thought it should. MY Very simple Rule is a 100 to 330 uF electrolytic at the Vcc connection, a .1uF cap per Ic and a 10uF cap for any board and increased by one every 3 IC's.
What Hasn't been mentioned well here is the inductance of the power supply leads and more important the traces carrying power on the PCBI. It's like a whole series of little inductors... in series with both power and grounds distributed across a board.
The Very best boards I Ever worked on had 4 layers top and bottom were grounded, more as an EMI shield that anything else, there was a Vcc plane, Split as necessary for ADC's and other more sensitive or low noise devices and an internal ground plane, Granted they were early Military stuff but there were no board issues and they were high speed synthesized radio PCB's... with 100 Mhz system clocks.
My design philosophy is very simple... You Don't have to populate the pads and holes... But it is sure hard to "Stick" em on later.
Place the parts on the board or at least the footprints... Stuff them all on the first copy and then remove the ones you think... extra, and see that your power supply is clean with an O'scope... If not start putting them back until it is.


Doc

Doc
1855  Development / Other Software Development / Re: [MOD] Arduino Enhanced Release 1.0.1B for Windows (installer, drivers, etc) on: August 30, 2012, 05:08:37 pm
Where is the "New Code" the "New shiny WINAVR"... I downloaded the Aug 13 version...

Doc
1856  Development / Other Software Development / Re: New Library for BiColor LEDs on: August 30, 2012, 04:52:37 pm
I apologize for "loosing" you but my "Rant" was about users that ASSUME that they KNOW everything.
If for example, you consider a 60Hz 10V PP signal... AC Right?, NO WRONG, a repetitive signal of 10 Volts amplitude only... repeating @ a 16.67 Ms interval.
The AC signal requires a reference of +5V. to recover the "Negative" part. It is still a 10V PP signal.
The basic concept of AC is a negative going signal... A Voltage that alternates polarity.
However polarity is a thing related to a "reference" point, usually 0 volts.
The point is that this signal Will pass through devices made for AC only.
Your alternating dc voltage will pass through a transformer... DC won't. Even a single pin from an Arduino coupled through a capacitor
with a repeating pulse present will pass both the transformer and the capacitor and be present at the other transformer winding... DC won't.
The capacitor isn't required but I included it to drive home the point about AC vs DC.
So it clearly isn't DC any more. To prove it is simple. It requires an external "reference" a pair of equal value resistors from Vcc to ground.
Measure from the center point of the resistors to the pin outputting the "Pulse" you will measure an AC 5 V PP signal.... at least on an Oscilloscope.
A DVM  will "average" or really mangle the signal But it is AC.

Doc
1857  Development / Other Software Development / Re: New Library for BiColor LEDs on: August 30, 2012, 03:31:22 pm
Pulsating dc and ac are the same, a variable flow of electrons. The primary difference is the "Reference"... If "AC" is "Referenced" from the most negative level them you could say "It''s Just pulsating DC.
Whether it is sinusoidal, square rectangular (duty cycle not 50%) triangular.
Come to think about the definition a little and you will see that the prime requirement for AC... The one Difference that sets AC apart from noise is just Periodicity.
It is the periodicity that sets it apart and allows it to do useful and predictable work is it's periodicity.
If you put in place a device that passes AC only, a capacitor or a transformer will pass your "DC" very well.
As to the library it does produce a signal that makes the LED light up Yellow... So the difference is?.. The LED works the same as if it had AC on it
Just the point of reference... Put it in the right place and your "DC" signal becomes "AC".
Place a diode in series and you remove 1/2 of the DC signal... Just as a diode would with AC... and you have DC again... pulsating but of one polarity... The signal cannot pull down when the input goes to it's lowest point because the diode will not conduct in the reverse direction.

Doc
1858  Using Arduino / General Electronics / Re: Driving a high power transistor on: August 29, 2012, 11:27:29 pm
A handful of BS170's, 2N7000's, or VN2222's are great too.

Doc
1859  Using Arduino / General Electronics / Re: voltage divider calculations on: August 29, 2012, 09:41:52 pm
That is the Finest Kind of learning... Also the way I've worked out Many, many different issues... I usually do my finest work in the shower... and I used to go to work with most of the previous day's issues worked out.

Doc
1860  Using Arduino / General Electronics / Re: Resistor Color Code Finder App on: August 29, 2012, 09:28:04 pm
Lefty, I agree with you 100% There is a great color code reference in Chapter 22 of the ARRL handbook...
Table 22.4
Resistor Color Codes
Color Significant Decimal Tolerance
Figure Multiplier             (%)
Black 0             1 { ? (0) }
Brown   1 10     1
Red      2 100    2
Orange 3 1,000
Yellow  4 10,000
Green  5 100,000                 0.5
Blue 6  1,000,000                0.25
Violet  7 10,000,000            0.1
Gray   8 100,000,000           0.05
White 9 1,000,000,000
Gold                   0.1         5
Silver                 0.0         10
No color                          20
This is a rough cut and paste from the handbook but the information has been in the "Public Domain" for so long, I have no issues with repeating it
There will not be a 3 or 4 band resistor with a 3rd band greater than blue or 000000 6 zero's. Not in the EIA standard list.
There is a big bunch of resistors that can be purchased from Amazon, for $29.00 you get 4550 resistors, All 1% metal film and Blue bodies, that for my old tired eyes, even with one of those headband magnifiers @ full strength... makes me grab my Fluke 179... just to make sure.

Doc
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