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1  Using Arduino / Project Guidance / Re: Webserver Security on: March 30, 2013, 09:32:06 pm
The cell phones would actually be on the same network, as these users always keep their WiFi on 24/7.  the WiFi network that they use is Secured with a WPA2 pre-shared key.  I'm not too concerned about WiFi sniffers.  I'm considering the cookie idea, but I'm not crazy about it.  Since they would be on the same collision domain, would it be possible to use MAC address?   I'm also considering using a Base 64 encoded user/pass handshake, however I feel that is about as secure as the cookie idea.
2  Using Arduino / Project Guidance / Webserver Security on: March 30, 2013, 05:04:49 pm

I am trying to create a web server to open an electronic lock, the electronics part and the web server part are already finished, however I am looking for the best way to secure this.  I would like to do a MAC address check on the user's that connect to the arduino so my users (not many) wont have to type in a username and password for convenience, as I am anticipating this page to be loaded on cell phones mostly.  Yes I am aware that a MAC address can easily be spoofed, but that is not something most users need to worry about, and this is already on a secure wireless connection on a private network.  Is it possible to determine the Client's MAC address through the Ethernet library?

I am currently using an Arduino Uno with the Ethernet shield attached.  I am planning on eventually switching it for the WiFi shield, however I do not have one at my disposal currently to test with.

If it is not possible to determine the connected client's MAC address, does anyone else have any suggestions of an easy way to secure this.
3  Using Arduino / Project Guidance / Re: Feasibility of a USB Matrix on: December 05, 2012, 01:34:40 am
Correct me if I'm wrong, but I don't believe one can use a male to male USB cable to connect multiple computers together.

Even if I could, how could I get one computer to be have as a USB flash drive to another computer (at the BIOS level) to be able to boot from the "drive."

Also if I were to daisy chain the machines, if one machine goes down I would loose the ability to work on any machines further in the chain.
4  Using Arduino / Project Guidance / Feasibility of a USB Matrix on: November 29, 2012, 05:53:31 pm

I would like to create a USB matrix that I can control through a web server.

basically I would like to have about 3-5 USB ports (will likely be USB Flash drives or External Disk drives) and as many USB host connections as I can. (I am running about 12 machines, and growing)

I would like to be able to from a web browser, "connect" any device port to any host port.

Example situation: I can load a Boot disk onto a USB Flash drive from a working computer, and switch it to the computer I'm working on to be able to boot from the drive.

My current thought process is to either use Transistors (not sure if I can for USB data signals) or relays, or if I can, simply put the data pins onto an Arduino, and let the Arduino control the switching, but I'm guessing it would take way too many pins to do this.  Another possibility is to use Multiplexers.

I am open to suggestions as to the best way to implement this.

Also would I need to reset the power signal to the affected USB drive every time a switch occurs?

Thank you in advance.
5  Using Arduino / General Electronics / Re: wiring a Relay board with a separate power supply. on: November 05, 2012, 11:14:45 am
I am working from memory (and the picture), I'm pretty sure the pins are (in order) Vcc, Ground, Int1-8, COM, and another Ground.  The last two pins have a jumper on them.  If i connect the ground to the arduino, how can I be sure that the relays are grounding to the power supply?  I will have 4 relay boards attached to this arduino so if the relays do not ground properly I will blow the arduino.
6  Using Arduino / General Electronics / wiring a Relay board with a separate power supply. on: November 04, 2012, 09:56:03 pm
I need some assistance on figuring out how to wire a specific relay board (5v version of with a separate power supply.  I have been googling this for a little while and I am finding instructions for other relay boards, but not this one.

Any guidance would be appreciated.
7  Using Arduino / Project Guidance / Re: Advice needed on Limits... on: October 08, 2012, 03:24:14 am
I also plan on setting up an additional LED in between the relay board and the Arduino board (one led per relay) to place on the project enclosure to display the status of the outlet in the server rack.  Will wiring up an LED in series add any current to the pin?  I don't believe this will add anything, but I would like to confirm before I blow the circuit.
8  Using Arduino / Project Guidance / Re: Advice needed on Limits... on: October 08, 2012, 02:49:39 am
you could make a simple excel spreadsheet & put everything in total it up easy enough.

That is how I came up with the pins that I did, but after 2 hours of working on it, I could have easily made a mistake along the way...  I'll just review the pins in a day or two after I lose my thought process.

Thank you for all your help, I'll keep updating this to see how it went.  After all the other parts get delivered.
9  Using Arduino / Project Guidance / Re: Advice needed on Limits... on: October 08, 2012, 01:44:30 am
After staring at a lot of numbers for the past two hours, I believe I am golden if I degrade from 32 Outlets, down to 31 outlets, using digital pins: 0-3, 5-9, 11-29, 38-39, and 42 rather than 18-49.

I realize I could use the analog pins for outputs to help cover my current constrains, however I opted not to as that would affect my string handling while retrieving the get commands from the buttons, and I can live with one less outlet.

If I use the pins above, I believe I avoid all other pins used by the Ethernet Shield.  With the pins above, if I have all my outlets turned on, and they are actually drawing 20mA (vs 15) The test conditions #2 & #4 that CrossRoads mentioned will be at exactly 200mA.  As the documentation states "[...]should not exceed[...]" I should be fine.  If anyone can confirm that using these pins (0-3, 5-9, 11-29, 38-39, and 42) should allow everything to work properly, I would greatly appreciate it.

I would love to test the board that I bought to see if it actually draws 15-20mA, however it hasn't been delivered yet.
10  Using Arduino / Project Guidance / Re: Advice needed on Limits... on: October 07, 2012, 10:24:05 pm
So using transistors I can trigger each relay using only about 6.25 mA (x32=200 mA) on each pin?  I apologize as I am terrible with transistors (I am trying to learn).  Also I thought transistors only effected volts, not amps.
11  Using Arduino / Project Guidance / Advice needed on Limits... on: October 07, 2012, 07:43:14 pm
Ok, I have an Arduino Mega 2560 Revision 3, with the Ethernet Shield (with the MicroSD card slot)

I have built a simple website to control the state of 32 relays, and thus 32 different computers. (future-proofing)
On the hardware side of things I'm only going to start with 8 relays.  I bought an 8 Channel 5V Arduino Relay Shield Module (Shield info: from a different website.  however I am thinking I may need to get an 8 channel relay board with Optical Isolation.  I am planning on powering each Relay shield with a different power supply.  My pins to control the relays are currently set to pins 18-50.   

My code is VERY incomplete and I am constantly modifying it.

code to do list:
change web server ON state to hardware pin LOW, as it is still reversed.
Pin 13 is added on there for test purposes, as I do not have the relays yet.
The button to Update the Machine labels is not functioning yet.
I am planning on saving the Machine labels and States to the EEPROM.
Create Authentication to protect the web server.
I would like to (eventually) interface the SD card to output a log of device changes.

I have attached my code as I was unable to embed it. (too long)

My Questions:
  • Will I have over-current issues when I turn multiple machines off (thus pins are HIGH)?
  • Will I have over-current issues with the ground with all pins set to low?
  • What should I use to power the relay boards?
  • I would like to unsolder the power connector on the Arduino and solder the wires directly.  Will I have any issues introducing heat to the board?
  • Does anyone have any recommendations as far as adding authentication to the board? *I have not researched this part yet, it may be a simple answer*
  • Any other recommendations for this project?

This is indeed my first Arduino project, so I'm sure I have made some noob mistakes along the way.

PS:  mods, if I placed this in the wrong section I apologize.

Thank you for taking the time to read this.
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