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polo2014
05-29-2008, 01:24 PM
WATCH THIS PLEASE: http://www.howcast.com/videos/866-How-To-Make-a-Water-Gun-Alarm-Clock

Guys I am not genius in these kind of things.. I am a Pre-Med major so i don't know much about electronics...
.......I NEED SOME SERIOUS HELP PLEASE ......

I would like to make this water gun sleep alarm project and i don't know what is this "Voltage Relay Switch" thing they are talking about in the video below.. I went to radioshack and found nothings like it, but the guy that works there said it was an IC looking, but he didn't see anything like it in the store..!!

he recommended trying the 555IC, but that thing is 8 legged, compared to the one they have in the video is only 6 legged !!! if i use the 555IC, how could it be done ? (the 555IC is 5V, so i need to use resistors if the alarm is supplying 9V.. what is the MATH ? what resistor do i need? I know it might be very simple for any of you. SO PLEASE HELP ME ....

I don't now anything about electronics, tell me what you think this "Voltage relay switch" is, and tell me if I need resistors or not or just tell me how can I do this project ....

http://www.howcast.com/videos/866-How-To-Make-a-Water-Gun-Alarm-Clock

Watch the Video and let me know,


Thanks,
POlo

Adrenalynn
05-29-2008, 02:32 PM
Firstly: For the love of all that is good and holy, PLEASE USE A BATTERY OPERATED ALARM CLOCK. House-socket 120v AC + non-purified water + sleepy person = 15+A across the heart. You don't need to be a premed student to see how bad an idea that generally would be. I would also prefer that you opto-isolated the buttons on the BATTERY POWERED alarm clock, but I also need to note that OSHA would require it. Even a single AA battery can deliver what OSHA would define as a lethal shock.

Secondly: For the love of all that is good and pure, someone teach that chick to solder. She makes us look bad. At the same time, atleast teach her to strip wires...

Ok, onward and upward. What the Radioshack Monkey was describing would look like this: bp3.blogger.com/_BQac7gcHPK0/Rkz1aGKBFoI/AAAAAAAAAXE/WafKmm1mOwg/s1600-h/555+IC+Timer+control+relay+Switch.jpg

Bah. Way too complicated. All we really want to do is switch low current...

I suspect what you have there in that video is what's called an "Optocoupler". I don't have time at the moment to dig up any part numbers, but it may be enough to get you started.

You don't really want to use a resistor to drop the voltage - current becomes an issue. Good design would suggest you use a voltage regulator to get your 9vDC down to 5vDC. Radioshack part number: 276-1770 - a standard 7805 1A 5V regulator. You can put 5+v (up to 35vDC) and get a solid 5vDC output without jumping through any hoops. If you're drawing more than a couple hundred milliamps, it should be heat sinked.

Unless someone else chimes in, I'll try to get part numbers for you tonight when I'm done for the day. In the meanwhile, you can also consider a low-trigger 5v reed relay...

polo2014
05-29-2008, 03:30 PM
WOW, This is a good start... but I am kinda scared now... LOL

ALL I KNOW from physics is that 0.02A or more for sure could be lethal..

The video seems safe from what i can see. the water is not touching any electric components to transfer lethal eclectic current!!

I will be waiting on your part #s.. Thank you for helping out

I might be asking too much here, but if you have time you can sketch a simple breadboard circuit and draw all the components that I need on it and show how to connect them to make this project work then it would be AWESOME... and when it works I will upload a Video and make sure to acknowledge you :) .. hehe, THANKS...

meanwhile IF anyone else would like to comment and help out then it will be greatly appreciated..

polo2014
05-29-2008, 03:33 PM
I will make sure I use a battery operated 9V alarm clock.. this should be safe right ? .. and the water shouldn't be transferring any electricity anyways!! its not gonna be touching any electricity to conduct any current ..

Adrenalynn
05-29-2008, 03:46 PM
Hi Polo,

More quick notes with more detail later. I'm bouncing in and out of a project and responding from the palmtop...

Any decent AA battery should be able to deliver more than an amp. A moderately good rechargable NiMH AA battery can deliver 2.7A for an hour straight in theory, and I've seen a 9v alkaline drop 4+A into a direct short to ground...

Water + Electronics is frequently construed as a BadThing. Are the odds good your gun is going to fire in a way that causes you to grab a good path to common ground across your heart? Probably not. But one has to weigh the consideration that I do this kinda stuff professionally. If I didn't note the safety considerations and emphasize them, in our litigious society I would not have employed Best Practice. I think I've pretty adequately warned you of the risks of mixing Water + Electricity. If you choose to move forward, I did my best and you carried on as an adult making your own decisions (still arguably legal in our society. ;))

Sorry Polo, I don't mean to be the proverbial Stick In The Mud, but I've just seen too many people point at someone else when something they decided to do went "Boom!"...

Adrenalynn
05-29-2008, 04:20 PM
Hmm, as I was cleaning the garage, a part number came to me from years gone by - a 4N28.

I don't know that I know what kinda voltage/current the speaker in that alarm clock puts out though. They just connect it straight up to the chip. The 6 pins leads me to believe that it has to be an optocoupler. I guess I need to put one on the scope [later]...

polo2014
05-29-2008, 04:34 PM
I totally understand..
but the project doesn't seem harmful in anyway, here is why ..

The water gun is being sold at target. All I am doing is triggering the water gun to squirt water at a specific time.
Its exactly like triggering the water gun manually to squirt someone, if its lethal to trigger it automatically then the gun it self is lethal to play with!! Right ?

I am not mixing water and electricity !! its already mixed in a safe way by who ever designed the water gun.. all the project is doing is make the trigger automatic.. how is it lethal ?

the water is in a water tank that comes with the gun. the alarm clock will trigger the motor in the gun to squirt water at a specific time, how could this be dangerous ? if its dangerous then the water gun itself is not safe to be sold.. coz am not really making a whole new water gun, am just making it automatic ...

Please.. think about it again and tell me if this could be dangerous after i have explained to you opinion.. I respect you opinion as you know more about electricity than i do. but logically is my project is not safe, the gun isn't safe to play with in real life...

make your argument, I might call the project off if you convince me with your view..

Thanks,
Polo

Adrenalynn
05-29-2008, 05:12 PM
I'm not really here to convince you or debate this particular application. With hacking comes unforseen consequences. It's something we either accept or don't. That squirt-gun went through severe product safety assessment. So did the clock. "No user servicable parts" - once you wire the two of 'em together, all bets are off. Notice how the switch [trigger] on that gun is sealed? It won't be anymore you're cutting it out.

So the thing squirts you, you reflexively raise your hands. You reach over to slap the snooze bar which has [whatever voltage the clock drops on it] running through the switch. Your wet hand makes contact and that open ground wire has ground potential with the water leaving the squirtgun. You just completed the circuit. The law of "Unintended Consequences" has just been fulfilled. Will it kill you? Probably not. OSHA says it can...

That's just one of those scenarios. I'm not saying "OMG! Don't do this! It'll kill you!", rather I'm saying "go into this with eyes-open and decide what the risks are". Would I do it? Naw. I don't like unpurified water around my electronics. [It also sounds like a crazy rude way to wake up]

Hey, we haven't even talked about you aspirating that water. You're the PreMed, I leave that one up to you. ;)

Anecdote:
I built a REM detector once employing galvanic skin resistance. I was really into lucid dreaming, and was looking for ways to detect the ideal state, as well as detect a lucid dream. I was largely successful. Anyway, the point being that even though my detector was running from the [email protected] USB, I was retentive about optoisolating my probes from my body and my detector from my USB PC. Even that circuit got whacked down when I was looking for UL approval for it. My isolators weren't good for more than 7500v, and a lightning strike would have killed someone using it... I got into redesigning it, then shook it off and just used it personally. I was willing to live with the odds...

Anyway, the upshot is that if their circuit actually works (again, I don't know what that speaker output delivers without putting it on the scope) you should be able to stick something like a 4N28 in there (check Digikey.com) and duplicate their results.

Alex
05-29-2008, 05:21 PM
All I am doing is triggering the water gun to squirt water at a specific time. Not exactly. What you're doing is triggering the water gun to squirt using methods involving electricity. Huge diff than finding other non-electric methods.

Anytime you have water shooting around electricity (your clock) you're taking a serious risk. All that needs to happen for you to get electrocuted is for the water gun to leak, get into the electronics of the clock and the alarm go off. Poof, no more waking up... ever.

Personally, I recommend you not do this project. Yes this project "sounds" cool in theory, but considering it sounds like you have no to very limited experience with messing with electronics, you're likely to get injured or worse. If you are going to do this project, DO NOT have a plug from the alarm clock anywhere near an electrical outlet.

Adrenalynn
05-29-2008, 05:42 PM
Actually, that's another good point. AC sockets and other things driven by line-voltage that may be in the neighborhood of the water's potential path, direct or indirect.

My mommy used to yell at us when we fired squirtguns in the house.

You know, another thing to consider are the creepy things that will be growing in your bedding. [shiver] I like critters but could probably live without the mold...

I outgrew wetting my bed... :D

All kidding aside, I'm glad to see Alex chime in here so I didn't continue looking like the lone wet blanket in this discussion [pun intentional]

Dave
05-29-2008, 05:44 PM
I am not mixing water and electricity !! its already mixed in a safe way by who ever designed the water gun.. all the project is doing is make the trigger automatic.. how is it lethal?

Don't let Adrenalynn scare you away from your project. She's just doing the responsible thing by letting you know what you're getting yourself into, since you're inexperienced with electronics. Listen to what she said, though. Don't mess around with water and wall-current, even if you think they won't mix in your project. Refer to Murphy's Law if you're still not convinced.

It's unlikely that you'll electrocute yourself by modifying low-voltage battery operated gadgets like a clock and a water gun. Keep this in mind, though: If that water gun sprays anything electronic, short circuits can result. Shorts, even in battery-powered gadgets, can cause fires and all sorts of other unpleasantness. You, or someone you know, may be operating this thing while half-asleep. Don't burn your house down.


I might be asking too much here, but if you have time you can sketch a simple breadboard circuit and draw all the components that I need on it and show how to connect them to make this project work then it would be AWESOME...

I hate to sound like the elitist electronics geek that I am, but... nobody here is going to design your project for you. You have to learn some of this stuff on your own. We're all willing to answer questions and point you in the right direction, though.

Adrenalynn
05-29-2008, 05:51 PM
What is this, you and Alex playing "Good Cop, Bad Cop" today, Dave? ;)

So what do you think - look like they just wired the speaker output straight into an optocoupler like an NEC2501 or 4N2* (27,28,29, whatever the heck they're up to these days...)?

Dave
05-29-2008, 05:57 PM
You know, another thing to consider are the creepy things that will be growing in your bedding. [shiver] I like critters but could probably live without the mold...

Ew. That hadn't even occurred to me. Yeah, why don't you make a Tesla Coil or something instead. Nice and dry, those things are.

Also, here's a helpful Instructable: How to Take Things Apart Without Killing Yourself (http://www.instructables.com/id/How-To-Take-Things-Apart-Without-Killing-Yourself/)

I'm not making fun; this is actually a very informative and useful article.

This is Step 2, from said article:

"UNPLUG THE #$!%ing THING! I AM NOT KIDDING! I KNOW EVERYONE THINKS THEY KNOW THIS, BUT STUPID PEOPLE HAVEN'T BEEN TARGETED BY THE WHO FOR WORLD ERADICATION, AND ACCIDENTS CAN AND WILL HAPPEN!!!"

Dave
05-29-2008, 06:02 PM
What is this, you and Alex playing "Good Cop, Bad Cop" today, Dave? ;)

Actually, that's our professional relationship, in a nutshell.


So what do you think - look like they just wired the speaker output straight into an optocoupler like an NEC2501 or 4N2* (27,28,29, whatever the heck they're up to these days...)?

It looks like it, but to be totally honest I really doubt it would work very well, if at all. I'd want to rectify and filter the signal before using it to switch something. Although "rectify and filter it" is pretty much my solution for everything.

polo2014
05-29-2008, 06:03 PM
OK guys. you do have some good points for sure ....

My plan is to make it where it mist water and not squirt it so it wouldn't reach such outlets and cause serious damage.

I will make sure No leaks are in the gun, + the gun will be actually far from the alarm clock.. I am not gonna put it on top of it !! .. I can also use purified water as a safety measure ..

with good cautions I think i can make it really safe, I just need to find out how to connect it 1st ..

LOL, anyone knows a more annoying way to wake me up ? I am a heavy sleeper .

Adrenalynn
05-29-2008, 06:08 PM
Actually, that's our professional relationship, in a nutshell.
Will you forgive me if I don't want to visualize how that translates into your personal relationship? :tongue: :veryhappy:



It looks like it, but to be totally honest I really doubt it would work very well, if at all. I'd want to rectify and filter the signal before using it to switch something. Although "rectify and filter it" is pretty much my solution for everything.

No doubt. My first thought was wondering how long the audio amp could possibly live with wild impedences like that... Thanks for chiming in on it. I wanted to make sure I wasn't losing the little bit left of my mind [that hasn't been lost in my garage the last couple weeks]...

polo2014
05-29-2008, 06:12 PM
You guys are awesome..

I am gonna proceed with the Project. Dave, thanks for the article.. I do build computers :) give me the parts and I can fire it up .. haha.. but I will make sure i read it ..

I will take all the safety measuremnts.. like stay away from outlets, make sure the gun doesn't leak, and I will keep the gun away from the alarm, + i will make it spray mist, not squirt water ..

Now what is that 6 legged thing ? I still don't know how to build it!! I need some help on that matter .. Thanks

Adrenalynn (http://forums.trossenrobotics.com/member.php?u=1711), Keep me updated on what exactly you think this 6 legged thing is.. or let me know if you got another way of doing this simple project .. and btw, I used to analyze REM data in a Neuroscience lab :).. great stuff..

Adrenalynn
05-29-2008, 06:14 PM
LOL, anyone knows a more annoying way to wake me up ? I am a heavy sleeper .

Yeah, now see, there's a good question!

How about a rag mop affixed to a 3000+ RPM motor? Chain drive. Just put it over the bed and the thing will beat the crap out of you when the alarm goes off. THAT would get you up, yes-sir-ree bob, it would.

In fact, we can even start building it right here from Trossen's catalog:

http://www.trossenrobotics.com/store/p/4222-5-1-28mm-Planetary-Gearmotor-RS-385-Motor.aspx

http://www.trossenrobotics.com/store/c/2694-Chains.aspx

http://www.trossenrobotics.com/store/c/3117-1-2-Bore.aspx

http://www.lowes.com/lowes/lkn?action=productDetail&productId=109776-15265-2001&lpage=none

Adrenalynn
05-29-2008, 06:16 PM
It's an optocoupler for sure. I have no doubt. But as Dave mentioned/concurred - it's a wonder it works at all as designed, and I doubt it'd work for long...

Dave
05-29-2008, 06:21 PM
My plan is to make it where it mist water and not squirt it so it wouldn't reach such outlets and cause serious damage.

Mist drifts. Might be worse than a direct squirt.


LOL, anyone knows a more annoying way to wake me up ? I am a heavy sleeper .

For fifty bucks, I'll come over and hit you with a folding chair when your alarm goes off :p

polo2014
05-29-2008, 06:23 PM
LOL how on earth would i build that thing , haha .. I like the idea, but thats painful .. I don't wanna go to work with blue eyes, hahaha.. but still how would i power it ? are you saying instead of trigger the water gun trigger this motor to beat me up ?

what would i need to connect the alarm clock to this motor ?or better questions to ask, HOW can i do it? Do i just connect the 2 wires going to the speaker to this motor :) .. sounds simple !!!

polo2014
05-29-2008, 06:24 PM
Mist drifts. Might be worse than a direct squirt.



For fifty bucks, I'll come over and hit you with a folding chair when your alarm goes off :p

LOL.. I just wake wake up in peace, haha

Dave
05-29-2008, 06:25 PM
How about a rag mop affixed to a 3000+ RPM motor? Chain drive. Just put it over the bed and the thing will beat the crap out of you when the alarm goes off.

The mental image of this just totally made my day. I'm gonna race you to the patent office with this one!

polo2014
05-29-2008, 06:27 PM
Originally Posted by Adrenalynn http://forums.trossenrobotics.com/ambience/buttons/viewpost.gif (http://forums.trossenrobotics.com/showthread.php?p=10461#post10461)
How about a rag mop affixed to a 3000+ RPM motor? Chain drive. Just put it over the bed and the thing will beat the crap out of you when the alarm goes off.



The mental image of this just totally made my day. I'm gonna race you to the patent office with this one!


LOL, what do i need to connect this to the alarm ? how can i do it :)

Dave
05-29-2008, 06:35 PM
Do i just connect the 2 wires going to the speaker to this motor :) .. sounds simple !!!

It's never as simple as it sounds. Gotta rectify and filter it first. It may also may require a polyrazmatizer circuit. Adrenalynn, I think our dreams of avoiding personal liability have just gone out the window.

Adrenalynn
05-29-2008, 06:35 PM
You laugh (and so do I), but I've been building something not too far off from this - and have a provisional filed. :P

My TubSpyder project is basically a car-wash inside your bathtub. I rotate three brushes at high speed, and I'm going to use a couple of the Solarbotics motors that just came in today from Trossen to power it down the tub. I've been waitin' for those!

Still, I agree, the mental image of someone getting the crap beaten out of them when the alarm goes off, spluttering and having their hands around, is just as hysterical as it gets in my day...

Polo - it's effectively the same notion, sans the water. You need to rectify and match the output from the speaker, feed it through an optocoupler, and feed the power to the motor from some higher current supply.

-------

Adrenalynn
05-29-2008, 06:39 PM
It may also may require a polyrazmatizer circuit.
Yeah, but you've gotta find a box of ohms first.



Adrenalynn, I think our dreams of avoiding personal liability have just gone out the window.

I'm almost willing to assume personal liability for a spinning rag beating the crap out of him every morning, and his cursing my name. Fame is fleeting, infamy lives on. That, my friend, is infamy.

polo2014
05-29-2008, 07:02 PM
OMY.. this is so freaking complicated .... gosh

Adrenalynn
05-29-2008, 07:16 PM
Why not use a sprinkler timer as a clock? A cheapie multizone could control multiple motors beating the crap out of you...

Alex
05-30-2008, 09:17 AM
LOL, anyone knows a more annoying way to wake me up ? I am a heavy sleeper .

Ok, a little late on this, but... how bout hooking a relay up to a tazer. That'll wake ya up quick... wait... aren't they meant for knocking people out?;)