I'm completely new to this! I do understand all the basic theory behind the arduino and have run some sample codes on it. I also have basic electronics experience in circuit bending instruments.
I have wanted to experiment with the aduino since I first saw I about a year ago but with so many project on the go I've just not found the time, until now. Actually, I still have no time but at least ive done the firststep and read through lots of info and got some boards, the problem is I need it to for a specific use and have no time to spare.
What I have is a 1.4 meter wide doorway, and a smoke machine, I want to sense people as they pass through the doorway to trigger the smokey. I was thinking of using the digital out pulse to close a relay for the switching. I also need to be able to calibrate the the length of this 'on' pulse (ON TIME) depending on the deployment of the smoke once the smokey's in place.
Next thing is the be able to change the amount of time before it is able to be triggered again (between 3-20 minuites) (DELAY TIME)
So my questions are.......
1.which sensor to use? I have the sharp GP2Y0A21YK but I see now this is more of a close proximity sensor about 80cm or less, so for a 1.4 meter doorway, it may not sense people who slip past one side of the door if I mount the sensor at the otherside, or kids if I mount it in the center above the door. A pressure sensor mat isnt an option so what sensors should I use?
Im not going to ask specifics about coding (not yet!) as i'm happy to give it a bit more thought first, using loop functions to do the timing. What I was wondering was if I could have a simple switch to change between say 4 different preset DELAY timings, so that other users can adjust the timings via hardware once i've calibrated them in via software. I think this should be possible as some sort of logic function with a 4way switch, what dyou think? Am I on the right track?
Sorry for the long descriptions and background info before I got to the questions, I wanted to explain the application and check I was on the right track. Most importantly, to move on I need to decide on the sensor first,
Sorry for the long descriptions and background info before I got to the questions,
No that is great, too many people ask questions without putting them in context and that of course affects the answer. We don't usually get to that point until about 6 posts in so it is very good to get a clear explanation.
great, perfectly straightforward! Not to me yet! thanks for your reply tho,
I was hoping to be able to get the the sensor and emmitter on the same side of the doorway to avoid wiring issues, but the doorway is actually 1.8 meteres wide not 1.4 so I don't know if that will be possible.
I followed your link and am sure I can knock up the sensor circuit (I have a broken freeview box at home I hope the rip the IR sensor and emmitter from) but how do I modify this to give me more power for the distance I need?
Also, the Sharp sensor is exactly this type of circuit just that its preset so I cannot adapt it for sensing futher? Am I right? But if i'm going to build my own I need to know how to set it up with values etc especially if I need two beams/sensors, anyone got any handy linc on this? I've tried searching for 'line sensor' but I'm mostly getting more complex things for robots to follow lines etc
I've seen people use a laser pointer and a photo resistor to make a laser break-beam sensor. The downside to this method is you would see the red beam of light as you walked through it.
I recently purchased the below infared sensor. It detects things up to around 50cm (19", not the 40" stated in the listing) away. Nice in that it only has to be mounted at one side as sensor and emitter are both in the same package. It interfaces directly with an Arduino input pin.
I decided to go with the paralax ping as it seems to have good enough range and is easy to implenent than my own IR emitter sensor circuits, I feel I sould have done it myself but I need this finished ASAP!
I've managed to write the code for the basic functionality I need and am quite uashamedly proud that it works as this is the first thing i've done with the arduino, so don't mock........
But.....more of an electronics question here.........which relay should I use? I have the ones pictured here in my bitsbox but have no idea how any of them are rated (except the one that says 12V coil on it) is the small black one likely to be 5V? (second from the top)
do you guys reckon it will be ok to switch a 12V circuit ? If not could anyone recommend a reliable, easy to intergrate to arduino, relay I can order in the UK, that would switch a 12V circuit (Usually on. I.e. push to break triggers the pulse)
I'm worried about just testing them incase I harm the aduino,
