Show Posts
Pages: 1 ... 121 122 [123] 124 125 ... 196
1831  Using Arduino / Programming Questions / Re: .pde to .ino, what replaces BYTE on: September 02, 2012, 11:47:39 pm
Yeah it IS... I have Prata's books on C & C++ and "A Book on C" and I get so confused I sometimes just want to quit reading anything. Beyond the real basics, precedence and basic rules of syntax and "grammar" they are more confusing than they were really worth. For all the good I got from "A Book..."
 I could have checked it out of the library and been done with it in a week... Instead of paying $18.++ for a really used book.
 cout << "I Quit" << end1; ...  printf(%s.... REALLY useful stuff. Struct's Unions and Enumerators... Pointers...
I finally realized they were a LOT more complicated than values and addresses...
Still makes me "Slightly Crazy" and I force myself to read 2 hours a day... Too.
I now know slightly more C & C++ than could be legibly engraved on the head of a Pin... And as was pointed out I learned 95% of it in the forum and a couple of Arduino specific books.

Doc
1832  Using Arduino / Programming Questions / Re: Goertzel or FFT for reliable DTMF Decoding on: September 02, 2012, 06:54:37 pm
 A Mitel MT8870 will give you 4 bit binary outputs and a data ready signal. The device contains the filters for the high and kw frequencies and decode @ < 100mV. I included thee data sheet and I've seen them on Ebay for $3 - $4.00. Much easier than devoting such a large piece of the code space for decoding... another note is that there are DTMF generators that use the same crystal... If you choose another time base only you could easily decode them. This was a common method for semi secure radio based remote control. I used it when building my first amateur radio repeater for shut down and phone patch control.

Doc
1833  Using Arduino / General Electronics / Re: Speaker or line-out jack... on: September 01, 2012, 04:04:40 pm
I stand corrected and I apologize for misleading you, I ASSUMED you meant stereo audio. A single circuit switch jack will do what you want to do for a monaural source. The suggestions about sensing when something is plugged in won't work as the sense signal... becomes part of the audio signal too. This idea has no merit...
From Magician: "Continuity testing usually works by passing a small amount of current throw 'through' a load"...
The "Load" is the Audio Amplifier input, not a place where you would want anything but Audio.
Re-read the post from me that begins "Quick one word answer NO. You have 4  2 wires that need to go to the jack...
The connection  methods would be the same however, just two wires less. Trying to use the speaker audio presents another issue as what "Switches" off the speakers when the Line In plug is inserted?.

Doc
1834  Using Arduino / General Electronics / Re: Turbo charger controller advice. on: September 01, 2012, 03:34:35 pm
I intended you to filter the 12V supply well and clamp it so that noise wouldn't be as severe as without the suggestions. and as I mentioned place a small capacitor "You have a source follower for the RPM data input... try a 1nF cap to ground from the source" (missing "across the 10K source resistor"). I did now (Finally) see a major mistake. In any control sutuation the grounding method should follow a star topology, that is all grounds must radiate or start at one common point and I don't see that done on your drawing nor do I see where the Arduino ground is connected... to anything. I am led to believe it must be the power connector on the board because you just don't show it. You don't show how the Arduino is powered at all and this point might well be central to the whole issue
Any spikes present on the gate of the Mosfet Must be transferred to the source circuit. Even though the Drain is tied to +5V it won't be dumped into the 5V source (the only place it can go except the input to the Arduino). A .1uF cap right at the drain lead, physically close to the drain. The issue comes back to the original design of the Arduino, It was meant to be a teaching device... Not a general purpose "Brick" for any control operation required... So when attempting to use it as a brick the user must be knowledgeable enough about the environment it is used in so as to be able to compensate or correct the "interface" between the Arduino and it's working environment. An Opto isolator is a solution. replace the 10K resistor with a 1K resistor and the opto... connect the transistor (collector) side of it from Vcc to a 10 K resistor and then to the Arduino input. You will have the same circuit as before. Presently when the gate of the 'fet is high so is it's source and thus the led in the opto will be on turning on the 5V source to the Arduino input. The other thing I don't see is any kind of a circuit that indicated any planning or fore-knowledge of an automobile's operating environment. Your drawing is more a statement of present conditions than it is a guide to a well thought out plan of action (Lack of power source for the Arduino, lack of any conditioning of the 12V source connected to the elements controlled by the Arduino. Primary side Sloane Kettering ignitions (Points and coil not electronic) versions can and DO have spikes many thousands of volts in intensity. There are Electronic ignitions that place 200 to 600V on the coil primary (Capacitor Discharge types). The Electronic ignitions use a magnetic sensor that produces a pulse that drives the controller to fire the spark plugs. That pullse can be upwards of 100V. Remember the points are now 4 6 or 8 "Lobes" on a shaft... causes a change  in the magnetic path when each "lobe" is adjacent the sensor coil. I've never seen a distributor that had TTL level outputs for engine RPM.
Since I don't see any formalization of plan and scope of this project I can only think you are creating it as you go along.
Good engineering Starts with an accurate plan... The instructions for building the device and when you deviate from the plan then you are working without planning exactly what you wish to achieve.There is an old design maxim... "Plan your Work, then Work your plan". IMO

Doc
1835  Using Arduino / Programming Questions / Re: How would I Set and Clear on: September 01, 2012, 12:41:31 pm
I fixed it...
I just threw it away as a bad receiver

Doc
1836  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
1837  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
1838  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
1839  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
1840  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
1841  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
1842  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
1843  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
1844  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
1845  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
Pages: 1 ... 121 122 [123] 124 125 ... 196