a simple project (hopefully)

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thielenm
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a simple project (hopefully)

Post by thielenm » Tue Oct 11, 2005 1:39 pm

very simple idea: a remote control buzzer. you push a button and it causes a device to buzz (wirelessly). I heard this can be done with picaxes. Is it possible?<p>The receiver and transmitter must be small especially the receiver. Can anyone tell me how to begin? It seems so simple but I have no clue.

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philba
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Re: a simple project (hopefully)

Post by philba » Tue Oct 11, 2005 2:27 pm

there are lots of ways to do this. picaxe would only solve part of the problem - you need a transmitter and receiver. Why don't you just get a transmitter/receiver. No processor (like picaxe) is needed.<p>try this or this or this<p>[ October 11, 2005: Message edited by: philba ]</p>

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Re: a simple project (hopefully)

Post by jimandy » Tue Oct 11, 2005 2:39 pm

Very simple solution:<p>Buy one of the cheap wireless door bells. Consists of a button for the door (transmitter) and a chime (receiver). Modify the receiver to meet your need. Available at Home Depot et al.<p>[ October 11, 2005: Message edited by: jimandy ]</p>
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Chris Smith
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Re: a simple project (hopefully)

Post by Chris Smith » Tue Oct 11, 2005 3:07 pm

Also toy RC cars can be cannibalized for this.

thielenm
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Re: a simple project (hopefully)

Post by thielenm » Tue Oct 11, 2005 3:27 pm

Those remote controls are expensive and the doorbell receiver looks way to big for me to use (13 bucks for the cheapest one too). I should be able to make this with just a few small, very cheap components but perhaps that is not possible?

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philba
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Re: a simple project (hopefully)

Post by philba » Tue Oct 11, 2005 3:43 pm

d*mn! duplicate post. dunno what happened.<p>[ October 11, 2005: Message edited by: philba ]</p>

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philba
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Re: a simple project (hopefully)

Post by philba » Tue Oct 11, 2005 3:47 pm

Yeah, its possible - all it takes is a bunch of cheap components but what's your level of electronics expertise? I sensed it wasn't high - that's why I suggested what I did. i doubt you will find an RF transmitter & receiver off the shelf any cheaper. Let me know 'cause I'll buy a bunch.<p>You could find a cheap RC car like chris said. One of those micro rc cars (like radio shack zip-zaps) might do it. you'd need to add a battery in place of the supercap they use. kind of short range, though.

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jollyrgr
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Re: a simple project (hopefully)

Post by jollyrgr » Tue Oct 11, 2005 4:04 pm

Thirteen bucks too expensive?!?!? NOW THIS IS A CHALLENGE!<p>I was at a Dollar General store Saturday (10/8/05). I don't know if these are in your area or not as you did not specify a location. Anyhow I bought two pairs (four radios) of FRS/GMRS radios at $10 for a two pack. That's right FOUR (4) FRS/GMRS radios for $20. And not some off brand but genuine Motorola brand radios. This is only FIVE DOLLARS PER RADIO! And they have a SIGNAL FEATURE with mute using "security tones" CTCSS. Thus you can secure this so the two radios only respond on ONE RF frequency and to the single coded squelch signal. Okay, that might still be too expensive.<p>Chris suggested RC cars; a great hardware hacker system. You don't need a giant car with expensive remotes and multichannel receivers. You can get these miniature cars (like the Radio Shack Zip Zaps) for about the price of a "Fun Meal". The RS Zip Zaps are on the expensive side but the knock offs run less than $10. There are some that are called MICRO RC cars. They have a drive motor and a steering actuator/solenoid of some sort. The off brand versions I've found at stores for as little as $4.95. These cars are smaller than a single AA battery. Here is a web site selling these (example only): http://www.hobbytron.com/Mini-Stunt-Veh ... ID=1411292<p>Turn the car upside down. Tape a "tape flag" to the wheels so that this flag flaps against the car's fenders. Push the remote button and listen to the tape "buzz" as it flaps the fender wells. The web site is only an example. I cannot recall for sure but I believe Dollar General had some of these as well. I know "Wally World" does but I don't know how much. You can remove the internal rechargable battery and install a real battery. (One, two, or four AA batteries depending on the model.) The receiver is about the size of a dime. I don't think even pager "stun" motors are smaller than the motors in these.<p>If you are in line of site, find an old VCR or TV (with remote) and remove the IR sensor. The IR sensor is usually a three lead device and is self contained. You have a +5V, ground, and OUT terminal. The OUT terminal will echo the pulse train from the received IR signal from a remote; any remote. Hook up a PIEZO or other speaker to the output of the IR detector and listen to the BUZZ of the data signal from the remote. (I've not pulled one of these apart and done this. I have made IR remote detectors using an IR photo transistor and OP amp. Works great.) <p>I am not sure what you are trying to do but the development/experiment cost to design your own will be more costly than the $13 doorbell. And even these I've seen on sale for much less. How low do you want this to go? To develop your own RF transmitter and receiver will be more expensive than using "Pacific Rim". If you are wanting thousands of these for a special project, then it might be worth the effort. But then you would not be asking in this forum. If you want one or a dozen, then I agree with others; get a ready made device. If you can come up with something cheaper, more power to you. But I think something like the $13 doorbell or the $10 PAIR of FRS/GMRS radios are too good to pass up.<p>As philba says, if you find something, post back and let us in on the deal.<p>[ October 11, 2005: Message edited by: Jolly Roger ]</p>
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thielenm
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Re: a simple project (hopefully)

Post by thielenm » Tue Oct 11, 2005 4:07 pm

Well actually I have a BS in computer engineering which is half electrical engineering material. I have experience programming microcontrollers and stuff but I still think I am very weak in general. In my opinion they don't teach enough practical material. Anways the main problem I am having is the transmitters and receivers are just too big or unnecesarily complicated for my application. I'd like to have a receiver that is very small and lightweight. I'd like to be able to make more than just one of these so buying something like a wireless doorbell doesn't really help because if I wanted to make more I would have to go back and buy more wireless doorbells. I want to have something I can duplicate myself very inexpensively.<p>Also perhaps a transmitter is not required. I know they already have these devices that beep when you whistle to find lost keys. Something like that could also work for me. Or something that just beeps periodically when turned on. As long as it could be made very small, very lightweight, and very inexpensively it would be a step in the right direction.

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Re: a simple project (hopefully)

Post by Tommy volts » Tue Oct 11, 2005 4:33 pm

thielenm,<p>If you like Jolly Roger's idea about using IR,
here is a neat project that you can use
IR Remote<p>It is cheap and relatively small and you build it yourself. I bought this kit several months ago.

thielenm
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Re: a simple project (hopefully)

Post by thielenm » Tue Oct 11, 2005 4:49 pm

It must work without line of sight =(

jimandy
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Re: a simple project (hopefully)

Post by jimandy » Tue Oct 11, 2005 4:51 pm

Here are a few problems with the subject.<p>1) You haven't hinted at your application so all terms like "small enough" "too expensive" etc. which are relative parameters make it difficult for the suggesters to make relevant suggestions. So for some of us, responding is like throwing darts blindfolded.<p>2) As far as costs go, miniaturization in electronics generally requires more expense on the "front end", i.e. development slope. The costs saving occur when production begins. But as an engineer I'm sure you know that.<p>3) Whenever RF is mentioned purists begin thinking about FCC rules,.<p>4) If your idea has profit potential and therefore too important to share in a public forum, you may want to make a legal disclosure to a private party to protect it as an intellectual property.
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Newz2000
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Re: a simple project (hopefully)

Post by Newz2000 » Tue Oct 11, 2005 7:36 pm

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by thielenm:
Well actually I have a BS in computer engineering which is half electrical engineering material. I have experience programming microcontrollers and stuff but I still think I am very weak in general... Anways the main problem I am having is the transmitters and receivers are just too big or unnecesarily complicated for my application. I'd like to have a receiver that is very small and lightweight. I'd like to be able to make more than just one of these so buying something like a wireless doorbell doesn't really help because if I wanted to make more I would have to go back and buy more wireless doorbells.<hr></blockquote><p>Did you check out the third link Philba sent you? It was to www.rentron.com and they have several inexpensive kits that look like they make connecting rf to a microcontroller a piece of cake.<p>I'm quite certain I'm going to buy one of these 4 bit sets to experiment with. The Oct 2005 issue of N&V had an article where the author made a funky looking doorbell using the kit.<p>Try this 4 bit kit for $20 that has everything you should need. If its not small enough, they have even smaller units available (for more money). Likewise, you could skip buying the HT-12D and HT-12E decoder/encoder chips from them and get surface mount versions elsewhere. These are the best value rf solution I've found aside from canabalizing from another device.

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Chris Smith
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Re: a simple project (hopefully)

Post by Chris Smith » Tue Oct 11, 2005 9:21 pm

Buy one, copy it, and make the rest your self?<p>Reverse engineering is big business.<p>[ October 11, 2005: Message edited by: Chris Smith ]</p>

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