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241  Using Arduino / General Electronics / Re: Questions on projects 02 on: May 11, 2014, 04:38:21 pm
Thank you to @Crossroads :
"The limit is 200 mA Absolute Maximum per VCC & Gnd pin, then the current limit per port and per pin.

'328P in a DIP package has 1 VCC pin, thus 200mA limit.
'328P in a surface mount package, thus a 400mA limit.
The Notes in Section 29 show the limits per port, totalling 300mA:

ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET] 304
8271G–AVR–02/2013
Notes: 1. “Max” means the highest value where the pin is guaranteed to be read as low
2. “Min.” means the lowest value where the pin is guaranteed to be read as high
3. Although each I/O port can source more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady stateconditions (non-transient), the following must be observed:

ATmega48A/PA/88A/PA/168A/PA/328/P:
1] The sum of all IOH, for ports C0 - C5, D0- D4, ADC7, RESET should not exceed 150mA.
2] The sum of all IOH, for ports B0 - B5, D5 - D7, ADC6, XTAL1, XTAL2 should not exceed 150mA.
If IIOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source currgeater than the listed test condition.
4. Although each I/O port can sink more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V)under steady state conditions (non-transient), the following must be observed:

ATmega48A/PA/88A/PA/168A/PA/328/P:
1] The sum of all IOL, for ports C0 - C5, ADC7, ADC6 should not exceed 100mA.
2] The sum of all IOL, for ports B0 - B5, D5 - D7, XTAL1, XTAL2 should not exceed 100mA.
3] The sum of all IOL, for ports D0 - D4, RESET should not exceed 100mA."
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test condition.hl
242  Using Arduino / Project Guidance / Re: Detecting a stepper motor position after a power cut / setting a home position? on: May 10, 2014, 12:14:43 pm
Quote
Another way I suppose I could do this is have the stepper motors return to their "home" positions on startup and then move it forward to the correct time.
This is the way to do it.
May be have your home position at 12, i.e. one limit switch per hand.
243  Using Arduino / Programming Questions / Re: Problem with Arduino LCD on: May 09, 2014, 08:02:48 pm
Yes
http://forum.arduino.cc/index.php?topic=97455.0
244  Using Arduino / General Electronics / Re: Powering my arduino uno from car battery on: May 07, 2014, 07:41:06 pm
You want to go from 12 to 5 so buy a step down converter.

I've used HERE
245  Using Arduino / General Electronics / Toggle Power Switch Circuit on: May 07, 2014, 01:46:45 pm
Came across this circuit, thought others may be interested in it for DIY designs.
FYI
https://www.youtube.com/watch?v=Foc9R0dC2iI&feature=em-subs_digest-vrecs
246  Using Arduino / Programming Questions / Re: Arduino Barcode Scanning on: May 05, 2014, 05:15:33 pm
Making multiple posts one the same topic makes people upset and wastes time.
247  Using Arduino / General Electronics / Re: DIY cases for you next project on: May 05, 2014, 02:04:01 pm
Quote
where they'd drilled out a pocket
That's a good idea.
You could cut the center out then screw/glue on the top and bottom.

You would be able to create some interesting shapes too.


Edit: this is also an interesting way to make a box:
https://www.youtube.com/watch?v=OiETlYskTrY&list=PL675D09BBDEA50DAB
248  Using Arduino / General Electronics / Re: DIY cases for you next project on: May 05, 2014, 01:48:58 pm
Page 2
249  Using Arduino / General Electronics / DIY cases for you next project on: May 05, 2014, 01:47:51 pm
This may be of some interest to those who have some woodwork skills.
250  Using Arduino / General Electronics / Re: What are good Mosfets to use with an arduino?? on: May 03, 2014, 11:57:04 pm
Lots of good reading here:
Click on Advanced Search in the top right hand corner of the screen.
Search for     MOS FET
251  Using Arduino / Microcontrollers / Re: Updating the mighty-1284p core on: May 01, 2014, 08:32:12 pm
@Coding Badly
Quote
# Full Swing Oscillator; Start-up time: 16K CK + 65 ms; Crystal Osc.; slowly rising power; [CKSEL=0111 SUT=11]
Quote
bobuino.bootloader.low_fuses=0xF7
You helped me out of a previous situation where I experienced 1284 problems on a bread application.
THANK YOU!
Others have not see the problem probably do to a different circuit layout, ground plane etc.
This points to my following conclusion, if several people have seen the problem and others not, there must be something borderline or on the verge of not working.
Since a slight change in layout fixes the problem, we are playing with a situation which can/could raise it's ugly head as a bug or intermittent.
I for one will always use full swing (at a small cost of power) as it totally solves the problem, besides I have enough problems laying in wait.
Thank you Coding Badly and Crossroads!
252  Using Arduino / General Electronics / Re: Hey guys, does anyone know how to use two breadboards with only one arduino uno? on: April 29, 2014, 06:11:35 pm
Just use a jumper from one bread board to the other.
Do you know how to use the power bars/rails on the bread board?
http://www.instructables.com/id/How-to-use-a-breadboard/
Or
https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard/all
253  Using Arduino / General Electronics / Re: Help me improve my dire first attempt at soldering on: April 29, 2014, 06:01:10 pm
Need more heat, less solder, liquid flux.
What diameter solder are you using?
254  Using Arduino / Project Guidance / Re: How to connect the Magnetic Sensor with arduino for my Tachometer Project on: April 29, 2014, 09:20:09 am
IMO use  a LM339.
May have to play with 20meg feed back resistor for your particular pick up coil.
255  Using Arduino / Project Guidance / Re: How to connect the Magnetic Sensor with arduino for my Tachometer Project on: April 29, 2014, 01:06:14 am
Look at page 18, this may be what you need or a facsimile  there of.
http://www.ti.com/lit/ds/symlink/lm339-n.pdf
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