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91  Using Arduino / Project Guidance / Re: Arduino working as a keyboard on: May 14, 2012, 11:54:32 am
Hey i think i'm trying to do somethign just like you. But what your trying to do. So you hit the button, the arduino sends serially, an A into the computer. Then if the other button is pressed it'll do a D instead.

If thats what your trying. It wouldn't be too hard to makeup a sketch on the arduino to send in one of those 2 letters when a button is pressed. Just a digital button tutorial doubled with a serial.print

as for the comptuer side of things. a couple of older useres of this froum told me to look up "gobetwino".
Its a nifty program that will let you do stuff based on a serial signal in.
Heres the website.
I'm still messing with getting it to work though, havent gotten to play with it yet. But it might be just what you need.

92  Using Arduino / Project Guidance / Re: About 2 years on: May 09, 2012, 10:40:31 am
iv got one thats been going for 5 months now its still running fine. And at work we have a couple that have been constantly running for a year and a half. So as long as your not doing anything horrible to it, 2 years should be fine.
93  Using Arduino / Project Guidance / Re: Video Calling Arduino on: May 09, 2012, 10:36:10 am
Hmm actually I think it could be done easy with the Gobetwino after looking at it.
I already have the comp waking automatically when you walk into the room in particular though. I'll play with this software though, if I can work it around to do a hotkey for the keyboard that should be good.

On the note of can she use a computer, no, shes 96 years old and can't see well. Thats why I was setting it up so that shed have it running using her TV as the screen so she can see better. But I'm not dealing with trying to teach her to use a computer or an IPad (which she wouldn't be able to see well enough either, I've tried). Took me 6 months to get her able to use her cable box.

and after testing out the camera because I've been going over for months and setting up using her TV and a webcam (fairly high quality). All her relatives have the IPad which is fine, but this old lady wouldn't be able to deal with that.

But thx for the Gobetwino. I'm pretty sure that that'll let me do what I need without having to learn to program a computer (though I should probably do that sometime anyways).
94  Using Arduino / Project Guidance / Re: breaking at 115200bps on: May 08, 2012, 01:57:50 pm
I've never had a problem with not getting data in the serial monitor.
Perhaps theres something happening in your code? Perhaps you could post it.
95  Using Arduino / Project Guidance / Video Calling Arduino *kinda solved* on: May 08, 2012, 11:51:42 am
Hey so I've come up with a crazy project from my neighbor (a nice old lady). So for a while, every now and then I go over to my neighboors house and setup my laptop on her TV with a webcam and all and let her Skype her family who live too far away to visit usually. And well for her birthday this year I'm giving her an older comptuer of mine. heres what I want to do for the project though.

What I'm building is a system, where with the press of a single button, (out of like 6 buttons, so like speed dials) she can do a skype call to her relatives with this computer. The comp will be hooked up to her TV (so its easy to see) and has a webcam setup facing her living room (they have 2 in the house, the normal one, and the family room, which people dont go in often, but this will be setup in)

Way it works, so the computer will be in hibernate mode, sitting there waiting. Walk into the room from either door, and it trips an IR beam by the door, which sends a signal to the power button on the computer to pull it out of hibernate and get ready (there will be plenty of time with her walking over to her chair). Then she can turn the TV on regularly, and it works normal or she sets it to channel 3 (she can handle that) which will be the output from the computer. Then using one of the several buttons (each large and labeled so she can read) it places a skype call to the person chosen, and goes through, fullscreens the videochat and all, then she enjoys watching her grandkids play with legos 2000mi away.

Now the buttons and the IR beams, are all done. the computer is over there and walking into the room will pull the comp out of sleep. And within the serial (using serial.print()) when you hit each of the buttons, sends a line that says like "call carol" or "call george".

My problem now is getting the computer to read those and put them into action. I've read a lot about peopel suggesting "Processing" as a language to use to program arduino related things that work on the computer itself. I've gone and played with a few of the tutorials (very graphically oriented of a programming language eh?) And I'm sure that with any language one can make a program that will read the serial port, and then click some buttons in series on the desktop.

What I'd like to know. I haven't done much with processing yet, I was planning on diving in fullscale tomorrow after my last final, and learning what can be done with that language. Should i go ahead and try the processing? Or would it be better to knuckle down, and actually go and learn regular C++ or Java or something to make it happen?

Yeah sorry not really an arduino question, but its interfacing with an arduino so I figured it might be valid.
96  Using Arduino / General Electronics / Re: Controlling Resistance Heaters on: April 25, 2012, 12:47:40 pm
but theres not too much running aroudn in these forums about 120VAC electronics.
That is because playing with mains when you don't know what you are doing is dangerous and can be fatal. I am surprised a teacher has given you this to do with so little knowledge of electricity. I would first check that your teacher is fully insured for when your parents try and sue over your death.

I would use a SSR solid state relay and turn it on and off at regular intervals to control the power. Get a relay that is rated at a current at least twice that you need to switch. The ratio of the on time to the off time determines the power. The code looks exactly the same as the code to flash an LED.

Perhaps I should note. This isn't an actual project. Its one of those kind of, end of semester. "Here go with this info and figure out how to do something like this". And get some xtra credit for doing a short essay about how you would do it. On of those deals. My teacher loves doing them. SO i figured I'd ask here, then over the weekend go find the guy who did my house's wiring and harass him for an hour. Basically what i had already was a relay controlled off of a switch, to turn the "heating units" off and on. But as far as temperature controlling. I understand its 1 thing to switch them on and off at certain setopints to keep the temp near constant. But with adjusting their output like a dimmer for lights. I'm sure there's more going on in a dimmer switch for lights in your house then just a potentiometer, so curiosity got the better of me and I didn't feel like waiting to ask the electrician so i threw it up here.

Gonna go up into the first statement and edit it stating its not actually something to build, shoulda probably mentioned it in the first place. However as it does stand. It seems a bit easier in the forums to get responses when asking about something that's over your head then for hypothetical projects.
97  Using Arduino / Project Guidance / Re: Building a ChronoGraph on: April 23, 2012, 03:25:33 pm
Id love to post the code but its at home, and im at school. Later this evening when i get home.

But suffice to say it goes something like this.

int count=0

Attach interrupt 0 [falling].
//Turn on SD read/writer and LCD screen


VoidInterrupt 0
not too much happening, just printing the count of pulses so far into an LCD screen, serial, and to an SD card (with an arbitrary filename, BBcount)

With regards to "its probably the code since its reading on the slower guns" In thinking about it, its probably more of cross section, and mounting problems on the guns. Why do I say this. Well pistols usually just have a little tip that sticks out, no fancy geometry or anything other then maybe a peep sight. When mounting the sensors to the 2 pistols I've tried, I get a small diameter plastic tube that fits over the end of the barrel. Mount the sensor and LED to that, and run. Its a lot more stable (and cuts across the BBs crossection better) then when I do it on rifles that all have some muzzle break that I have to try and mount the LED and sensor to.

Perhaps I can get the CNC teacher @ my school let me borrow a machine for a little while and cut something out of a piece of nylon stock or something. With nice low tolerance drilled holes to mount everything in that slides onto the equipment rails of one of the guns, to do the sensing. That'll account for any improper mounting.
98  Using Arduino / Project Guidance / Re: Building a ChronoGraph on: April 23, 2012, 02:38:05 pm
Using an interrupt since if im not mistaken, thats the fastest sensing capability of the arduino is it not? And yeah 545km/hr is fairly fast. THats a pertty standard outdoor projectile speed though. Many guns however fall into the 350fps range (~380km/hr for AWOL).
It probably is however the BB is too small to block out the light enough for the sensor. Though I know when I tried to do this on a couple pistols I have, it sensed just fine. So probably speed coupled with the small cross section.

So then, what could one do then to make the sensor read better, cause I cant really change the size of the BBs in the gun.

TY btw
99  Using Arduino / Project Guidance / Building a ChronoGraph on: April 23, 2012, 02:11:17 pm
Hi there, so I've been mulling around this project in my head a little bit. SO I built a rig that uses IR leds/IR recievers to sense when a BB was going out of the barrel of an airsoft gun (counting ammo usage through the course of a game). And I had a little bit of trouble with actually getting a signal off of some guns.

I'm wondering, what might have been causing the problem. I doubt that the arduino is running too slow to pick up the pulse. I think, assuming a 5mm bb, going say 500fps,
Thatd be the 5mm turned into inches is ~.2in, to feet thats .016ft for the bb's cross section. .016 divided by the 500f/s gives you the amount of seconds that the BB takes to go by a point (the sensor), then multiply that by 1000 to get the number of milliseconds that it takes to pass by.

So .032ms, too fast for the arduino to pick up? Or is my math wrong?
Or is there a better way overall to go about this?

100  Using Arduino / General Electronics / Controlling Resistance Heaters on: April 23, 2012, 02:08:16 pm

So I've been thrown onto a project to make some resistance heaters work, gotta melt some plastic for my teacher. So the heater is 800W and runs on 120 V AC, Which that should be ~6.6Amps. Now thats low enough it should (keyword should) run off of a wall outlet correct.

How would one control the temp of the thing though, I was thinking of using the kind of knob off of an electric oven. But what is that itself, just a big potentiometer? From what I've been told, working with AC isnt as simple as dropping in a resistor to limit current.

Thanks ahead of time, and sorry for whats probably a dumb question, but theres not too much running aroudn in these forums about 120VAC electronics.

Edit. To note, this is a project, for an end of year, xtra credit essay. No actual heating system will be built.
101  Using Arduino / Project Guidance / Re: magnetic coil gun on: April 23, 2012, 01:18:09 pm
Well what are you using for a projectile. One thing you should probably do is make the coils themselves a bit bigger (the look from the picture like they onyl have about 20 turns in them). Also since I'm assuming your projectiles are probably nails with the heads ground off, you might want to switch the nails themselves. Some nail steels aren't as magnetically active as others. Though that will come down to trail and error.

If you've got a few working coils though, and aren't too worried. What you can do, take 3 coils, and place them right next to eachother. Then a little down the line do another bank of 3, and farther down another 3. Set them all up with their own relay, but in a manner so each bank of 3 will trigger at the same time.
(With doing this, itll give you the power of 9 coils, but the complexity of 3) then it comes down to doing testfires and trying different timings. Probably will have to use micros in the timing really.
You might be helped severely by throwing together a chronograph (actually im gonna ask advice on the forums about how to make one here in a few mins) And testing the speed of the projectile at several steps of the firing.

Another experiment you might try, do 3 banks of coils. 1,2,2, coils. Hook it up so that on firing, first all the coils are triggered, each having its own cap to run. After passing coil 1, the second 2 banks are triggered again, drawing power off a second set of caps (also taking another few couple relays). As it passes the second bank, the last 2 coils trigger again, along with another set of caps. That means that at initial, the projectile will have the highest acceleration, and then as it moves through the barrel, gets sped up again by the new fresh charge from your second cap bank. Then right before it leaves the barrel, gets another last burst of significant power. This can only work though if you have measured out the speed at several points and can trigger the coils at the right time.

Also it lets you use all your coils. If the explanation isnt clear, later on ill draw a diagram. I tried to do this once with my own coilgun. But as it would happen, there was too much current going through the projectile, and it had a habit of melting the plastic I made the barrel out of.
(I was using it as a conductor to make the contact for the subsequent coils. To alleviate needing computer timing, note this was long before learning of arduino lulz) Yeah it was a dumb idea, but charging single coils at a time, it worked great.
102  Using Arduino / Project Guidance / Re: Can someone go over my code please? 16ch chicken incubator on: April 23, 2012, 11:59:50 am
One thing though. I don't think you can have a Millis based timer with a 2000ms delay within your code. I'm pretty sure thatd cause a problem. You could, for example, make it so that that delay is a millis one.
Sure you can. millis() is a clock. delay() uses the clock to know when it is done wasting time.

Hmm I always figured that a delay stopped the loop from operating for that time though. So, if he were to have something with the 2 sec delay, but then something that should happen every second because of a millis timer, then the millis timer would also end up working at the 2 second mark (since itd be past the 1000ms interval anyways). Meh i guess ill try something out when i get to my dorm later.
103  Using Arduino / Project Guidance / Re: magnetic coil gun on: April 23, 2012, 11:09:11 am
Based on my experience trying to build coilguns. So what I believe your saying.

1 you built a few coils yourself with some 22 gauge wire.
2 Your firing something down a 1/4 in tube for your barrel (what are you gonna use for projectiles?)
3, You've got your capacitor bank built out of disposable cameras, as well as the charge circuit.

Ok so what your planning on doing is making the arduino trigger the relays on in series to accelerate the projectile more efficiently.

That means turning on the first relay, then as the projectile passes shutting it off, and turning on the next. ANd having an individual capacitor bank for each coil.

Its not surprising you broke your multimeter, caps they have in disposable cameras can store more then enough power to hospitalize someone. Odds are, your relays wont trigger fast enough to get the series right (unless you lengthened the barrel, but then theres more friction). And with that much power as your first coil project, theres a very high chance your gonna hurt yourself. You say 22 AWG wire. How much voltage can the insulation take though?

Try something simple. 1 Coil, 1 cap/charger, and 1 relay (get something with high voltage and current ratings). Get that to work off your arduino (jsut have like a fire button on the arduino) Then move up to adding more coils and caps.

To note, its a lot easier to have a pair of coils on top of eachother each getting less power then it is to have 1 coil with 2x the power in it. And its safer. Now go experiment. I don't wanna see a news report of some guy hospitalizing himself with a homebrew coilgun though.
104  Using Arduino / Project Guidance / Re: Can someone go over my code please? 16ch chicken incubator on: April 23, 2012, 10:51:46 am
That is one of the most organized homebrew circuit boards I have ever seen. Props to you man.

Though using arrays definitely will make your life and following your code a bit easier. A for loop would probably help too.
Reads sensor, calculates temp. Switches relay if needed. Moves on to next pin. And then just does this repeatedly.

For getting the actuator to tilt the egg trays a little though. One thing, is it supposed to be like a sudden, over a minute it does the 45 degree shift, or does it gently go back and forth over the course of the hour? And what kind of signal does it take to operate the actuator?

As for the millis command.
Since you're already using the basic blink without delay to turn on and off the incubator lights I think. Its probably good to mention that you can have other intervals to do sections of code at. Each one will need its own previous millis (so like prevmillisincubator, prevmillistilt) and then jsut have the different while loops activate as needed at different times.

One thing though. I don't think you can have a Millis based timer with a 2000ms delay within your code. I'm pretty sure thatd cause a problem. You could, for example, make it so that that delay is a millis one. If you've noticed, does you LED on your arduino only blink every 5 seconds or is it off and on every sec? (haven't tried putting both a delay and a timer in the loop at the same time, always figured it'd cause problems. If it doesn't, well then I learned something coming here today).
105  Using Arduino / Project Guidance / Re: fiber optic balloons on: April 17, 2012, 12:00:58 pm
Which is heavier, 100m of fiber, or a watch battery and Nano?

I dunno, they got some pretty big watch batteries out there. =P

I think some kind of radio communication would be the best way to go, even with a "large balloon" Cause theres no way you could lead any kind of signal wire up 500ft to a balloon unless you were going for something truly massive.

The newer xbees can reach over a mile range IIRC, and they're mad easy to use, though they are a bit power heavy if you were gonna run off a watch battery. Though, how big is this balloon gonna be.
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