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76  Using Arduino / General Electronics / Re: Control DC motor with transistor 2N3055, pwm from Arduino on: December 21, 2012, 04:36:41 pm
An IRL3103 should work.  The RDSon increases to about 0.016V at 4.5V VGS (close to typical at an MCU output).  That would mean about a watt of dissipation at 7.6 amps.  Given a typical TO220 I think it will get to about 60 degrees above surroundings at your maximum.  Okay for the FET, but you won't want to touch it or keep it cooped up.

I use little heatsinks when I push TO220 devices to a watt or so.  Kind of like these: http://www.aztecmcu.com/catalog/i99.html

They still get warm, but not so hot they could burn you or melt something.
77  Community / Products and Services / Re: Introducing the Omega MP shield and Aztec on: December 19, 2012, 05:15:40 pm
I've bought quite a bit of stuff off these guy's.  Including that programmer.  Very nice!

Selection on components is not huge, but their prices are hard to beat.  They also have some other unique stuff I've never seen elsewhere.

Thanks guy's!
78  Using Arduino / General Electronics / Re: Control DC motor with transistor 2N3055, pwm from Arduino on: December 16, 2012, 10:08:25 pm
VCEsat is also 3V @10A, so there will be 30W of heat to dissipate.  Well within the capability of a 2N3055, but it will require a fairly big heatsink nonetheless.

May I suggest an IRL540 MOSFET?  It could be used by itself and would not even need a heatsink with a gate drive of 5V and a drain current of 10A.  It can handle sustained currents of up to 28A and peak/pulse current over 100A, so it should be able to cope with stall and start conditions fairly well.
79  Using Arduino / General Electronics / Re: A Cautionary Capacitor Tale on: December 16, 2012, 09:42:47 pm
Are you all using metric or imperial measurement?  I am seeing references to standard sizes that are used in both measurement methods.
80  Using Arduino / General Electronics / Re: Is Converting voltage to frequency similar to creating a tone? on: December 16, 2012, 09:20:14 pm
I believe if the frequency range of the VCO (Voltage Controlled Oscillator) output is within the frequency range of the recorder, then yes, this should work fine.
81  Using Arduino / Microcontrollers / Re: Loading bootloader to an Atmega8U2, easiest way? on: December 10, 2012, 06:51:21 pm
Quote
I believe that is one of the programmers that cannot power the target chip

I believe so as well.
82  Using Arduino / Microcontrollers / Re: Loading bootloader to an Atmega8U2, easiest way? on: December 10, 2012, 06:25:33 pm
Some programmers can supply power through the ICSP, some can't.  So the quick answer is, it depends on the programmer you choose.
83  Using Arduino / Microcontrollers / Re: How to bootload/program an atmega328p at 1.8v on: December 09, 2012, 09:00:20 pm
Adafruit's USBtinyISP programmer has a jumper to supply 5V to the target or not. When the jumper is not in place, no power is supplied, and the logic levels are shifted to match the target's supply. I've used one to program target boards operating at 3V and 3.3V, but not 1.8V, so I'm not 100% sure that it will work. I do think I'd stick to ICSP programming and forget the bootloader.

They do this by running the 74HC125N buffer off the target board's voltage.  The 74C125N is spec'd to run down to 2V, so probably won't function well at 1.8V.  Even if it could, the ATtiny2313 would not recognize such low signals coming back on the MISO line.  I think 3.3V or thereabouts is the lower limit for reliable operation of the Ladyada USBTinyISP.
84  Using Arduino / Microcontrollers / Re: How to bootload/program an atmega328p at 1.8v on: December 08, 2012, 09:31:02 am
Could you not build  level shifter board and use ISP?
85  Using Arduino / General Electronics / Re: The PERFECT Arduino Programmer. on: December 08, 2012, 07:10:02 am
What about something like this? http://aztecmcu.com/catalog/i105.html

I use mine so much I have dedicated an older Duemilanove to it.

Putting an ISP connector onto your board is another way to go, but you still need a programmer.  I would imagine you also need to allow for ISP in your circuit design.  You could easily have things attached to the SPI pins that would prevent you from using them for ISP.

86  Using Arduino / General Electronics / Re: Circuits and suitable Parts for using with Electric Gear Retracts on: November 25, 2012, 03:49:24 pm
The Model i have in the build stage has a span of 88", would you still recommend servo's. smiley-confuse

That's a pretty big model.  Then again, there are some pretty powerful servos: http://www.ebay.ca/itm/JR-Z9100HVT-High-Voltage-High-TORQUE-Servo-JRPSZ9100HVT-/350486772564?pt=US_Character_Radio_Control_Toys&hash=item519aa3bb54

87  Using Arduino / Microcontrollers / Re: Burn Bootloader to ATmega 8-16PU using an Arduino Uno on: November 24, 2012, 03:25:49 pm
@Kenny_ken,

I just tried what you described with a new ATmega8-16PU and it worked just fine.  Make sure all your connections are made properly like in the tutorial simplex mentions.  It should work.

I long ago gave up the jumper wire method and got myself a little shield that makes it a pleasure.  This is the one I use: http://aztecmcu.com/catalog/i105.html

Its just so much easier than trying to debug the rat's nest each time it goes wrong.

Edit: BTW, what is the error message you are getting?
88  Using Arduino / Microcontrollers / Re: Loading bootloader to an Atmega8U2, easiest way? on: November 24, 2012, 10:43:03 am
I don't think the bootloader goes on the '8U2.  It needs the USB to serial communications code.  The code they put on the original UNO's 8U2 might work.  It should be available from the Arduino site some where.  The bootloader would go on the '2560.

Either way, you'd need your ISP programmer to put the code on them.
89  Using Arduino / Microcontrollers / Re: Can you use the arduino usb2serial lite as a ISP on: November 24, 2012, 10:37:32 am
I bought one of these: http://www.ebay.ca/itm/AVR-Programmer-Works-with-AVRdude-and-Arduino-IDE-/280890704478?pt=LH_DefaultDomain_2&hash=item416664025e

Cheap, fairly versatile and works pretty good using a serial connection, but it needs a real RS232 port.

Otherwise, there are tons of USB based AVR ISP clones out there pretty cheap too.  Some better than others.  Like this: http://www.ebay.ca/itm/New-USB-51-AVR-ISP-Programmer-Downloader-USBASP-usbisp-/261111862849?pt=LH_DefaultDomain_0&hash=item3ccb7ad641

Never used one though, so can't vouch for it, but you can't beat the price.
90  Using Arduino / General Electronics / Re: floating voltage at the output of a light sensor (with arduino Uno rev 3.) on: November 24, 2012, 10:07:52 am
Yes, for sure.  Solder the short end of the pins into the sensor board, then you can plug it into the Arduino properly as the longer end of the pin will make better contact with the Arduino socket.
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