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1  Using Arduino / Project Guidance / Re: Opening and closing gate on: January 18, 2013, 03:11:39 am

Thank you very much for your responses smiley

@Quick5pnt0 how do I find out this information? I could go out and get a multimeter today but I'm not sure how to use it. I believe it's momentarily where I press the switch the gate starts opening, even when I release the switch, (sending the switch into an "off" state), the gate will continue to open until it's reached it's programmed limit. After then when I press the switch again, the gate will start to close.

@coltstrgj there is no keycode per se, it's controlled wirelessly via remote control or an indoor switch (it seems that the remote triggers a relay). I chose to connect the relay to the photographed switch since the location of the switch is within close proximity to a LAN port and a wireless access point (I prefer to use the access point to conserve ports).
Perfect. If you could get another remote, you could have a servo or motor easily press the button, or you could wire in to that same relay that you mentioned. You should also look at the arduino wifi shields, I have not worked much with them, but it shouldn't be too hard.
2  Using Arduino / Project Guidance / Re: Opening and closing gate on: January 17, 2013, 10:46:36 pm
Hi. This is entirely possible, I have a door to my dorm room that opens by checking my email, the problem is making it. With a little more info I could help better.
First, how is the gate opened now? Is it electric with a keypad? If not (and it is manual) then there is two ways to do this. First you could have the arduino unlock the gate, and not actually open it, or the harder but much cooler option is having the gate actually open for you. If your gate is just a manual gate you will need to chose if you want this to be easy or "Hard".
If the gate is already automated somehow, you will(probably) need to crack open the controll box, are you ok with that? You could also have the arduino just punch in your code for you if you dont want to open it up, but this would be something that I have never messed with.

My last question is: Have you ever worked with arduino's or other micro-controllers? This is not neccesary, but it helps. Any prior programming knowledge also helps alot.
3  Using Arduino / Project Guidance / Re: Arduino and Android on: January 17, 2013, 10:35:02 pm
If you get(or make) a micro usb to plug that Is able to plug into the arduino there are apps that can do serial communication and other simple stuff(some do more) I think that this would be the cheapest and easiest option for you to do. I personally used a female to female usb connector, and just plugged my phone charger into the arduino cable. I leave the phone charger end hanging out in the hall at my dorm, and use serial communication to open the door(with a servo). I now also have a py script that checks my email and opens it, so this is obsolete unless im in a hurry.
4  Using Arduino / Project Guidance / Help with using Arduino Uno i/o pins as both input and output on: January 17, 2013, 10:27:43 pm
The short version: suggest a small relay or transistor (Preferably transistor) that I can turn eight of on with a single output pin on the arduino.

The long version:
I have looked for a way to do this, but I have not really come up with a good way to word my search. If there is a simple way for me to look, or a simple solution please tell me and this topic will be removed.

The "problem" is that I would like to use the pins (2-9 specifically, not that it matters that much) as an output, and an input within the same sketch. My code is fine, but I need help with the design of the hardware. I would like a way to have the pins 2 through 9 to have led's connected to them, but also to be able to detect input (not at the same time) I planned on using transistors as switches for the led's so that the led circuit would not effect the outcome of the digitalRead(and get a false HIGH) but because I have eight of them, the remaining pins 11, 12, and 13 were not strong enough to open the transistors wide enough to keep the LED's bright. Is there any transistors that I could drive 8 of with one pin. If not is there any that I could drive 3 of. I would like to keep the whole thing powered by the arduino(with usb), with no relays. If I do get new transistors, how should I wire them. I currently have all of the base pins and the collector pins wired together (not base to ground, but ground to ground, and base to base but i assume that you knew that) and then each of the collectors this is likely where my problem is, but I can not think of another way to do It. I am not looking right now (I am home for Winter break, and I switch between my parents houses) but I think that the collector line is wired to ground, and the base is to pin 13. The emitter goes through the led, and then to the output pin. Unless I have forgotten something very important(which is probably true) that is the only way to wire it, and get the leds to light when I need.
I could use relays if need be, but I would prefer not to. If i do end up needing to use relays, I would like a suggestion of small ones that are fairly cheap. I would also need to know how to run all of them off of a single (or three) pins on the arduino. I assume that if I just wired them in series that they would all get activated, but I am not sure.

Thanks in advance for any help.

5  Using Arduino / Installation & Troubleshooting / Re: Detecting input as High when not actually active. Arduino uno r3 on: January 11, 2013, 07:49:31 pm
Show us how you have the project wired in a schematic.
I cant take a picture at this time, as I do not have the board with me(I also can not try it with only pin 9) but here is a picture That is not photoshopped in any way of the same exact design as I used. I just unplug the wires that I do not want to detect as HIGH and plug them in when I do want them to.

Unconnected pins are "floating" and will read high and low randomly.

Use the internal (or external) pull ups to fix it.

I will try this. Thank you for showing me this. I figured that a pullup would not be needed in this case, but you are probably correct, I will try this when I get home.
6  Using Arduino / Installation & Troubleshooting / Re: Detecting input as High when not actually active. Arduino uno r3 on: January 11, 2013, 12:17:23 am
Also If I left any info out please forgive me, I will edit the post if you just tell me what I forgot.
7  Using Arduino / Installation & Troubleshooting / Detecting input as High when not actually active. Arduino uno r3 on: January 11, 2013, 12:16:33 am
Short story: pin 9 detects the input as high, even when there aren't any wires in it(so no way to detect a input) Other pins have the problem also, but only occasionally. Why would this be happening. I have tried if(digitalRead(pinNum) == HIGH); and if(digitalRead(pinNum) != 0); neither seem to work. I have not tried reversing the logic (subtracting from 255 instead of adding from 0) but I do not see why that would make a difference.

The long story:
I wrote a small bit of code that would detect input on pins 2-9 and return the integer value (the input represents binary. This is for part of a  project to help introduce kids to binary, it is a calculator that also outputs in binary on leds. The rest of the project is working) For some reason pin nine always returns as HIGH and some of the other pins do sometimes also. I have noticed that It is only the PWM pins on the last few trials, but this is likely just a confirmation bias, because I think that at one point there were a couple registering incorrectly at a time. I made a separate program just so that I could prove to myself that my other code was not interfering. Now all that the program does is output to serial what pins are detecting a HIGH input.
I have never powered the arduino from anything other than a usb port, so there is no reason that I see that it should have fried. Should I put a resistor inbetween the 5v rail and the input pins? if so how high of a resistance? Do I need a pull down resistor (from the input to ground) to be sure? I would have thought that just having the connection break would be enough, but as we can see what do I know.
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