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1  Using Arduino / Sensors / Re: Laser tripwire with modulation. on: October 16, 2013, 10:36:32 am
i would not use the 38kz. its a standard that is used for about anything that controlled or controls something through infrared. your security system could be defeated by a learning remote. generally i dislike the security through obscurity model, but it might be your best bet here.  just write a function that loops through your own defined patterns of off and on that can be detected and predicted by the device on the other side. kind of like morse code spelling out a phrase, but dont use morse code. 

if you want to be very fancy, you can use the HOTP token based one time password generating/authenticating algorithms using a base32 shared secret. the algorithms can be difficult to understand, but are just a series of math operations so not too hard to implement.

as far as hardware, ive had good luck with old garage door blockage sensors or whatever, that keep you from closing the door on top of an obstruction.

hope this helps
2  Using Arduino / Sensors / Re: Problem writing to the MFRC522 with Arduino Uno R2 on: October 16, 2013, 10:16:31 am
the example code here has write support. i havent tried it as i have no writable tags yet, but it compiles fine and works just fine for reading tags at least. it does look like it function-izes all the commands so you dont have to mess with the hex.

as a note: if you sign up with TI you can get free samples of rfid tags, theres only a few that are 13.56mhz but you can get 5 of each of up to 5 products so 25 tags smiley they have one of the best and most generous and unstingy samples policy, probably to retain some market dominance
3  Using Arduino / Programming Questions / Re: Midi controller info on: June 29, 2013, 09:17:34 am
im wondering if you were able to get this operable. im about to set out on basically the same project. custom MIDI controller with an arbitrary design. but also with the ability to act as a midi "hub" in order to funnel through a device with only one input/output. ill check out the project in the link, so i apologize if any of this is specifically addressed there.
4  Using Arduino / LEDs and Multiplexing / Re: Multiple Max7219s and LedControl Library on: June 14, 2013, 08:29:32 pm
would you mind terribly posting a schematic or description of your wiring? im trying to do the exact same thing as you. im nowhere near new to electronics, just arduino... kind of.  id like to confirm my schematic before i go soldering... i doubt these cheap displays could handle much desoldering/resoldering and id like to make sure i get it right the first time
5  Using Arduino / Storage / Re: Arduino + USB Host + SATA Drives on: May 30, 2013, 11:19:44 am
man i wouldnt even say that online.  i dunno the political climate where you are, but here they really got no sense of humor about that these days.  we all know youre joking, but it could in theory be used against you, out of context.  that being said, make a model rocket launcher.
6  Using Arduino / Sensors / Re: Need help with my ultrasonic sensor on: May 18, 2013, 02:10:35 pm
it could not be both, evaluation proceeds left to right. order of operations.

if you are using multiple modules in proximity to each other, i could see them "hearing" each other

i recently got a HC04 or whatever. i found a library, but was unsatisfied with it, and ended up changing all but a handful of lines. let me know if you want the code arduino@pyrotuc
7  Using Arduino / Microcontrollers / Re: Arduino on ATtiny - which core ? HLT, or Arduino-tiny or another? on: May 16, 2013, 01:00:58 am
what method are you using to burn your chips?
8  Using Arduino / Microcontrollers / Re: ATtiny85 w/ tiny-core and serial write on: May 16, 2013, 12:43:56 am
so basically, there is a specification in the standard for 12v, but some "smarter" interfaces will bend over backwards to be overly compatible?

anyway, i just got a number of these chips. excited to try them out cause their cheapness opens up new options...
9  Using Arduino / Microcontrollers / Re: Programming ATTiny24 (and 44/84 of course) on: May 16, 2013, 12:34:08 am
think this will work on an 85? i just picked up a couple of these at tayda ( )  I will try it on the morn. seems like these would be *perfect* for building a fleet of sensors with an extra kick, smart switches, automation/security features... 6 pins...hmm... 6 pins.. how to use them...

so glad there is already a known way to use these things, seems like at that price they open up all sorts of new possibilities.... muwahahahhaa 
10  Using Arduino / Sensors / Re: Honeywell HIH 4030 Humidity Sensor Library on: May 07, 2013, 08:04:53 am
i recently got some HIH-4602-A and C sensors as samples from honeywell. ( ). which is awesome of honeywell as the sensors are around $80 each.

ill need to compare datasheets, but it looks like they work in a similar manner to the 4030s. if i need to extend your library, are you down? or you think just use it as a template and make a separate one? thoughts? comments?
11  Using Arduino / Sensors / Re: How to Sense Voltage ( AC Main Line ) using arduino ? on: April 19, 2013, 08:46:52 pm
also, theres things called hall effect sensors you may want to look into, but i dont know if they would be appropriate for what you are trying to accomplish.
12  Using Arduino / Sensors / Re: Where to get sensors for weather station? on: April 19, 2013, 06:06:24 pm
maxim carries a number of these sensors, and will ship you samples for free. i just got a ds1620 from them.

honeywell makes some combined temp/rh sensors, and will also send you free samples

in fact, if you just search for "free sample IC", you will find that there are TONS of products you can get for free just by asking nicely.  i probably got $500 or so worth of free products from a dozen different companies recently, just by asking nicely. if they dont have a "samples" link on their website, just email customer service and explain yourself. i only had one place decline me because i wasnt a hot-shot with plans to buy 1000 or more eventually.
13  Using Arduino / Sensors / Re: ds1620 on mega2560r3/1.0.3 on mac, library wont compile on: April 19, 2013, 05:44:35 pm
nevermind, i ditched that library and found a newer one that works.

i only managed to pull half my hair out, luckily.
14  Using Arduino / Sensors / ds1620 on mega2560r3/1.0.3 on mac, library wont compile on: April 19, 2013, 05:31:05 pm
when i try to compile the example in ruben lagunas ds1620 library i get strange errors that im not sure how to fix

/Users/kristucker/Documents/Arduino/libraries/ds1620/ds1620.cpp: In member function 'void Ds1620::rst_low()':
/Users/kristucker/Documents/Arduino/libraries/ds1620/ds1620.cpp:127: error: 'LOW' was not declared in this scope
/Users/kristucker/Documents/Arduino/libraries/ds1620/ds1620.cpp:127: error: 'digitalWrite' was not declared in this scope

can anyone point me in the right direction? im thinking it was written for a old version of the compiler and needs to be updated, but im not sure how to do it. ive gotten tons of other code to run with little to no problems... frustrating!
15  Using Arduino / Storage / Re: Need help writing data to text file on SD card. on: April 19, 2013, 04:51:20 pm
for the life of me i cannot get the ds1620 library/example to compile. i have tried installing it in a bunch of different places, no luck. it tells me HIGH is not defined and LOW is not defined, i try including like every other library i have, still no luck. i think it is because i am using 1.0 of the compiler and these were for <1 of the compiler because they are .pde this is the first code problem ive had that i havent been able to figure out, and searching all over and i cant figure out what i need to do. can anyone help?
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