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16  Using Arduino / Project Guidance / Re: Arduino Prototype Drawing Software on: March 24, 2013, 05:29:15 am
its written in the picture you linked:
http://fritzing.org/

its free
17  Using Arduino / General Electronics / Re: Arduino mega tutorials and breadboards on: March 24, 2013, 05:21:31 am
there is no need for mega tutorials as  you can usually just use the code from uno for a mega. only thing you gotta do is maybe change the pins in the code.
when u have a breadboard and a multimeter and put it to resistance detect mode you will realize how the breadboard works in less then 3min.
or you could go to wikipedia... and see stuff like this, which pretty much explains it
http://upload.wikimedia.org/wikipedia/commons/e/ec/Breadboard_scheme.svg
also as a beginner you might wanna look into this http://fritzing.org/
18  Using Arduino / Project Guidance / Re: trust ebay new arduino for beginner? on: March 23, 2013, 05:12:45 am
if you buy from china then go directly for mega 2560.

you get them for 17$
http://www.ebay.de/itm/190814363717?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

its just as ready as any other arduino/clone


Quote
Go to the Installation and Troubleshooting part of this forum. Read a few posts. You will soon see that if you buy a clone Arduino for a low price, you will soon be on the forum asking why it doesn't work
could you point me to some posts?
I see a lot of posts with clones, but not where the clone is the origin of the problem. on the other hand i find posts about a not working bootloader, then 5 replies if its an original, in the end it is and still not working...

http://arduino.cc/forum/index.php/topic,150421.0.html
http://arduino.cc/forum/index.php/topic,148037.0.html
http://arduino.cc/forum/index.php/topic,155569.0.html
19  Using Arduino / Project Guidance / Re: Detect approaching car/detect distance from home on: March 18, 2013, 12:10:35 pm
i havent read the replies, so i dont know if this was mentioned:

i dont think thats a good idea at all. cats climb on trees, go through bushes. if she gets stuck eg while jumping she might be strangeled to death. I wanted to build a rfid cat door, while doing some research ive seen horrible pictures of cats with collars, even with those which are suppossed to break in a dangerous situations
20  Using Arduino / Project Guidance / Re: Looking for Feedback on a PCB design on: March 13, 2013, 05:35:44 pm
I got curious and took a look. in eagle schematic library search for component *wirepad*. Its vias which can be used as connectors in the schematic
21  Using Arduino / Project Guidance / Re: Looking for Feedback on a PCB design on: March 13, 2013, 04:07:45 am
-i would really rearrange your components, you have a lot of space so better place them to save lots of long routes and moving around corners, switching between bot and top layer. just remove all routs and look how you could improve it

-you still can put in a ground planes covering the complete pcb for bot and top. its very good for absorbing and dissipating heat.

-you still should read this, http://www.sparkfun.com/tutorials/115
and use those clearances

Quote
I just needed holes to connect wire leads to. How is that typically done?
-you can use a termin screw block as u can find under con-phoenix, vias is a good idea too, but i would clean up that design and place them properly like in the first picture at one spot

-i would really rearrange your components, you have a lot of space so better place them to save lots of long unnecessary routes and moving around corners, switching between bot and top layer. just remove all routs and take a look on how to improve it

-i would use 45° angles on all those corners and not ur 90°, like in this picture http://www.sparkfun.com/tutorial/Eagle-DFM/Routing.jpg  just use the 2nd and 4th routing mode
-u still use weird angles eg right side - bottom
-i guess u still didnt try that drc file, which gives like 100 design rule errors

-you could transform a via into a library part for eagle, so you could use the via as a connector in your schematic, there are plenty of tutorials eg youtube, also then eagle would give you airwires for those and tell you if any lines cross or something like that
22  Using Arduino / Project Guidance / Re: Looking for Feedback on a PCB design on: March 12, 2013, 03:26:49 pm
the big IC on the right: the silkscreen border line is made out of bottom layer... it should be on silkscreen layer

go to this site:
http://www.seeedstudio.com/depot/fusion-pcb-service-2-layers-p-835.html?cPath=185

its a typical pcb service... read what they want from you for ur pcb
there download the eagle design rule file to check if your layout is consistent with most of their needs for production

check this too http://www.sparkfun.com/tutorials/115

try to make straight lines with 90° angles, even top and right outline of the white boardline are not in 90°, maybe you need to zoom in in your screen to see it, if you right click the top outline and click properties you can adjust the position of the line, try 0.72 and 0.72 for the two fields on the right side

also try to increase the resolution of your routing grid, makes it easier to place all the routes in a proper way

also what do you use these "connected vias" for? u dont have something like that in the schematic
23  Using Arduino / Project Guidance / Re: Looking for Feedback on a PCB design on: March 11, 2013, 03:58:35 am
do this:
http://dangerousprototypes.com/2012/07/18/eagle-polygons/

why dont u use like really horizontal or vertical lines but those awkward angles

with better placement of components i think you can avoid switching between top and bottom that often
24  Using Arduino / Project Guidance / Re: Guidance required - home automation on: March 07, 2013, 01:43:26 am
i dont know if i got it right:

datasheet says: OPERATING FREQUENCY RANGE: 47 to 63 Hz

pwm above 50Hz -> u wont see leds flickering
25  Using Arduino / Project Guidance / Re: Project qurrey on: March 04, 2013, 06:40:23 am
with those electrodes its like putting two cables into the water, you get a connection, once the water is below that lvl u will open the circuit. but would not be a good idea for ur cupstuff.

with that pressure: imagine it like this: the cup is standing on some sort of small ballon, or maybe the end of a syringe. to that ballon or syringe u attach a pressure sensor. Depending on the weight of the cup the pressure value changes.

another type of sensor: maybe measure acceleration of the cup, so you know a sip was taken but not how much
26  Using Arduino / Project Guidance / Re: Feasibility of "vending Machine" type lockbox? on: March 02, 2013, 03:11:47 pm
Quote
and 14 switches for each of the key holders.

maybe u need just a linear stepper, how about this: the keys r put into something similar to a revolvers cylinder, where u put the bullets in.
Infront of that cylinder is a plate with one closed opening. If they right code is put in the linear motor rotates the cylinder to the right position and then the second motor opens the door and people can take out the key
27  Using Arduino / Project Guidance / Re: Project qurrey on: March 02, 2013, 02:58:22 pm
you could maybe measure the weight, or use a force sensor or pressure sensor, or u could put electrodes in different heights to open a circuit when the water left that height, you could use level/floating sensors positioned at different heights
28  Using Arduino / General Electronics / Re: What are the difference between soem condensator on: March 02, 2013, 07:56:31 am
google helps in 2sec
http://www.learnabout-electronics.org/ac_theory/capacitors01.php

the element is a resonator

i think the voltage means that the capacitor is resistant up to a voltage of that value
29  Using Arduino / General Electronics / Re: transistor selection help on: March 02, 2013, 03:48:14 am
like this one irlml2502
http://www.irf.com/product-info/datasheets/data/irlml2502.pdf
its super small, super cheap and can handle a lot more then u need


this is german but might help anyway: -u need one of those where it says logic level, then look for the needed package
http://www.mikrocontroller.net/articles/MOSFET-%C3%9Cbersicht#N-Kanal_MOSFET
30  Using Arduino / General Electronics / Re: transistor selection help on: March 01, 2013, 04:49:44 am
hi,
not necessarily, u need to calculate the watts, then look at the datasheet °C/°K per Watt, calculate the heating above ambient 25°C, then look at the case of ur transistor eg to220, To92, and see how good it dissipates the head and then decide wether u need a different case or what kind of heatsink

ive done this only one time so i maybe get it wrong, so it would be nice if someone with more knowledge looks over this:

Forward voltage of bc337  1,2V x 0,48A = 0,576 Watts  (0,625 W max Rating - thats way too close)
thermal resistance from junction to ambient 0,2 K/mW  -> 0,2 K/mW x 576mW = 115,2°C +25°C ambi = 140°C   way too hot

id recommend u use mosfets
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