need help with a senior project for college

Now that's putting the "senior" in "senior project" (sorry, I couldn't resist. I was born in '62 -- you're young).

There are transmit/receive module pairs out there that you can get, that are easy to interface to. I have no idea what your budget is, but that'd be the easy way to go.

--
www.wescottdesign.com

Yes I agree with Tim it would be much simpler to use prebuilt and tested RF modules here is a good selection.

Google also "Micrel's QwikRadio"

Or if it's line of site you could use IR (infrared) cheaper and easier and no problems with FCC etc.

So are you. I was born in 52. :)

--
Greed is the root of all eBay.

to

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:)

us

d

You and Tim are the best! It's a place to start!

However, I need to make sure they have schematics, I need to ORCAD the thing out and make my own board

Depending on where you are in the world, there are relatively inexpensive transmitters and receivers on 315mHz (US) or 433mHz (rest of the world).

315mHz transmitters and receivers are available on Ebay for $3US each, plus shipping. They have a range of more than 50 feet (haven't tried further).

transmitter:

receiver:

If you're not in the US, search for

433 transmitter and 433 receiver

John

And *I* can claim a one-year seniority over *you* :-) When I first came to the sci.electronics groups years ago, I expected most posters to be much younger than me. But it gradually became evident that such was not the case.

I also often take part in a computer forum hosted by an Indian publishing company. I enjoy interacting with people young enough to be my children and grandchildren with the exuberance and brash confidence of youth. But there are times when it gets a bit too much and I stay away for a few months. On returning, I usually find a few posts and private messages asking where I'd gone.

One thread starter's post that brings up a smile every time I think about it asked, in all sincerity, up to what age a person keeps growing wiser. The OP and some others thought that a man reaches the peak of wisdom in his early twenties.

To the OP: I aso think adapting an existing module would be your best option.

You and Tim are the best! It's a place to start!

However, I need to make sure they have schematics, I need to ORCAD the thing out and make my own board

-----------------------------------------------------------

Try

and search for rfPic. They have an inexpensive development kit. I bought one at one of their Masters conferences a few years back but never used it. They also have wireless solutions using ZigBee, IR and WiFi. Their app note AN242 has schematics and even board layout and BOM and antenna design. It uses 433 MHz with ASK modulation, and is FCC approved.

Here's an article:

They also have an excellent technical forum where you can get help from other Microchippers and PICkers. Here's their Zigbee and Wireless forum:

rfPic:

Good luck, young whippersnapper... I'm 60 :)

Paul

IF you follow the Rentron link I gave you they have demo schematics typical applications.

You can find a typical application schematic in pdf as well as other relevant stuff here like supporting components etc.

Bottom of the page.

TWS-434A RF Transmitter Module

Same applies for the

RWS-434 RF Receiver Module

If you browse the site they should have a project using both modules. Ah here's one project using them.

:I am a 50 year old fart who got hurt at work and qualified for :vocational rehab and am getting my second AS degree, this time in EE. : :For my project, I want to modify my 85 year old Mom's tea kettel, so :when the steam blows, it spins a dc motor to provide current to a :roulette wheel circuit to llight LED's, the LED's stopping as a cap :discharges. : :However, since she is stone deaf almost, I also wanted to add a board :to the design that generates an AM or FM signal to a remote device :that lights up an LED next to her chair : :Any help on designs for AM/FM transmitters/receivers that I can use :the output to be the power that activates a switch that turns on an :LED? : :Most of you guys are way beyond me technically, so, please be :gentle! :) : :I already have a circuit for the roulette wheel, I am copying a :previous advanced digital circuit we did in class, but I wanted to use :some of the outputs to send an RF signal and need help with finding :similar frequency range transmitters and receivers. : :I found several versions of fm and am transmitters and receivers but :none of the frequencies match, some of the transmitters are HF band :and others are commercial band, most FM transmitters are commercial :band : :I just need something simple I can use and if you can tell me the part :numbers with it, please??

Before you get to the remote sounder part of the design (that's relatively simple with the transceiver modules mentioned) you should spend some time on thinking through a reliable boil detect system. Your idea of using the steam pressure to spin a fan motor is cumbersome, and to my mind, impractical - especially for an elderly person. I would abandon this idea and use a detector which monitors the current through the kettle heater element. I envisage that when the kettle is switched on the heater current passes through a single turn primary (heavy gauge wire) on a small toroidal transformer which is then stepped up by a suitable turns ratio to provide a voltage source suitable to trigger say a 555 which then takes control of all other subsequent functions. I would mount all the electronics in a box which has a normal mains cord and plug at the input and a a mains output socket into which the kettle is plugged. The circuitry could be configured to flash the LED and sound the remote alarm for a suitable time period before resetting ready for the next operation.

stepped

say

input

I envisioned a non-electric kettle. But I also remember there used to be bits on the old kettles that would whistle when the kettle was boiling, which then would allow for something to be triggered by the whistle.

I didn't really think the project was well thought through, though I wasn't sure whether the point of the project was to be innovative, or to learn and display practical skills like soldering and such. If it's the former, then I'm not sure enough time has been spent on the sensor, and the wireless link is just gloss that would often be handled by commercial modules in some other setting. If it's about practical skills then I guess it matters more to show off how to solder and build an actual working project.

Michael

What might be even more practical and also a good safety product in general, would be a combination of a timer as well as a "dry pot" detector for electric stoves and other appliances. I have considered adding this to my hot plate after I have several times forgotten about a pot of water and luckily smelled the hot metal or Teflon lining after it had gone dry, but before it melted or disintegrated onto the floor or counter.

Usually one can guess how long it will take to heat a pot containing a certain amount of water, and the timer can be set to about that long. But it should also be possible to determine when the pot has gone dry, because as long as there is water in it, the temperature should not be much above

100C. But as soon as the water evaporates, all the nergy of a 1000 watt or more element will go into heating a rather thin piece of metal and it will soon reach several hundred degrees. An alarm would be good, but even better would be a relay to turn off the supply to the element.

Hey, I might even *buy* something like that! I can make it myself, but I know I never will.

Paul

Children :-)

I was born in 43

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
                                             (Stephen Leacock)

:On Fri, 5 Feb 2010, Ross Herbert wrote: : :> On Tue, 2 Feb 2010 17:55:29 -0800 (PST), Jim Bancroft :> wrote: :>

:> :I am a 50 year old fart who got hurt at work and qualified for :> :vocational rehab and am getting my second AS degree, this time in EE. :> : :> :For my project, I want to modify my 85 year old Mom's tea kettel, so :> :when the steam blows, it spins a dc motor to provide current to a :> :roulette wheel circuit to llight LED's, the LED's stopping as a cap :> :discharges. :> : :> :However, since she is stone deaf almost, I also wanted to add a board :> :to the design that generates an AM or FM signal to a remote device :> :that lights up an LED next to her chair :> : :> :Any help on designs for AM/FM transmitters/receivers that I can use :> :the output to be the power that activates a switch that turns on an :> :LED? :> : :> :Most of you guys are way beyond me technically, so, please be :> :gentle! :) :> : :> :I already have a circuit for the roulette wheel, I am copying a :> :previous advanced digital circuit we did in class, but I wanted to use :> :some of the outputs to send an RF signal and need help with finding :> :similar frequency range transmitters and receivers. :> : :> :I found several versions of fm and am transmitters and receivers but :> :none of the frequencies match, some of the transmitters are HF band :> :and others are commercial band, most FM transmitters are commercial :> :band :> : :> :I just need something simple I can use and if you can tell me the part :> :numbers with it, please?? :>

:>

:> Before you get to the remote sounder part of the design (that's relatively :> simple with the transceiver modules mentioned) you should spend some time on :> thinking through a reliable boil detect system. Your idea of using the steam :> pressure to spin a fan motor is cumbersome, and to my mind, impractical - :> especially for an elderly person. I would abandon this idea and use a detector :> which monitors the current through the kettle heater element. I envisage that :> when the kettle is switched on the heater current passes through a single turn :> primary (heavy gauge wire) on a small toroidal transformer which is then stepped :> up by a suitable turns ratio to provide a voltage source suitable to trigger say :> a 555 which then takes control of all other subsequent functions. I would mount :> all the electronics in a box which has a normal mains cord and plug at the input :> and a a mains output socket into which the kettle is plugged. The circuitry :> could be configured to flash the LED and sound the remote alarm for a suitable :> time period before resetting ready for the next operation. :>

:I envisioned a non-electric kettle. But I also remember there used to be :bits on the old kettles that would whistle when the kettle was boiling, :which then would allow for something to be triggered by the whistle.

You may be correct. I haven't used a hotplate heated kettle for so long I failed to consider that the OP's mum might not be using an electric kettle.

: :I didn't really think the project was well thought through, though I :wasn't sure whether the point of the project was to be innovative, or :to learn and display practical skills like soldering and such. If it's :the former, then I'm not sure enough time has been spent on the sensor, :and the wireless link is just gloss that would often be handled by :commercial modules in some other setting. If it's about practical skills :then I guess it matters more to show off how to solder and build an actual :working project. :

Since the OP's elderly mum has to use the thing, it also has to be simple to use AND reliable. Even using a hotplate type kettle I can't see how these two criteria could be met using a fan motor turned by the steam emanating from the spout of the kettle as a temperature sensor.

If the OP does in fact mean to apply his idea to a non-electric kettle then it would be far simpler to use a 1N4148 or similar diode mounted in a short section of sealed diameter metal tubing inserted into the kettle spout as a temperature sensor.

On Thu, 4 Feb 2010 21:45:32 -0500, "Paul E. Schoen" wrote:

: :"Ross Herbert" wrote in message :news: snipped-for-privacy@4ax.com... :> On Tue, 2 Feb 2010 17:55:29 -0800 (PST), Jim Bancroft :> wrote: :>

:> :I am a 50 year old fart who got hurt at work and qualified for :> :vocational rehab and am getting my second AS degree, this time in EE. :> : :> :For my project, I want to modify my 85 year old Mom's tea kettel, so :> :when the steam blows, it spins a dc motor to provide current to a :> :roulette wheel circuit to llight LED's, the LED's stopping as a cap :> :discharges. :> : :> :However, since she is stone deaf almost, I also wanted to add a board :> :to the design that generates an AM or FM signal to a remote device :> :that lights up an LED next to her chair :> : :> :Any help on designs for AM/FM transmitters/receivers that I can use :> :the output to be the power that activates a switch that turns on an :> :LED? :> : :> :Most of you guys are way beyond me technically, so, please be :> :gentle! :) :> : :> :I already have a circuit for the roulette wheel, I am copying a :> :previous advanced digital circuit we did in class, but I wanted to use :> :some of the outputs to send an RF signal and need help with finding :> :similar frequency range transmitters and receivers. :> : :> :I found several versions of fm and am transmitters and receivers but :> :none of the frequencies match, some of the transmitters are HF band :> :and others are commercial band, most FM transmitters are commercial :> :band :> : :> :I just need something simple I can use and if you can tell me the part :> :numbers with it, please?? :>

:>

:> Before you get to the remote sounder part of the design (that's :> relatively :> simple with the transceiver modules mentioned) you should spend some time :> on :> thinking through a reliable boil detect system. Your idea of using the :> steam :> pressure to spin a fan motor is cumbersome, and to my mind, impractical - :> especially for an elderly person. I would abandon this idea and use a :> detector :> which monitors the current through the kettle heater element. I envisage :> that :> when the kettle is switched on the heater current passes through a single :> turn :> primary (heavy gauge wire) on a small toroidal transformer which is then :> stepped :> up by a suitable turns ratio to provide a voltage source suitable to :> trigger say :> a 555 which then takes control of all other subsequent functions. I would :> mount :> all the electronics in a box which has a normal mains cord and plug at :> the input :> and a a mains output socket into which the kettle is plugged. The :> circuitry :> could be configured to flash the LED and sound the remote alarm for a :> suitable :> time period before resetting ready for the next operation. : :What might be even more practical and also a good safety product in :general, would be a combination of a timer as well as a "dry pot" detector :for electric stoves and other appliances. I have considered adding this to :my hot plate after I have several times forgotten about a pot of water and :luckily smelled the hot metal or Teflon lining after it had gone dry, but :before it melted or disintegrated onto the floor or counter. : :Usually one can guess how long it will take to heat a pot containing a :certain amount of water, and the timer can be set to about that long. But :it should also be possible to determine when the pot has gone dry, because :as long as there is water in it, the temperature should not be much above :100C. But as soon as the water evaporates, all the nergy of a 1000 watt or :more element will go into heating a rather thin piece of metal and it will :soon reach several hundred degrees. An alarm would be good, but even better :would be a relay to turn off the supply to the element. : :Hey, I might even *buy* something like that! I can make it myself, but I :know I never will. : :Paul :

The main problem with these sorts of safety devices is that they must be manually mounted to the cooking utensil itself every time the user puts the utensil on the hotplate. I don't think the majority of people would be bothered to do this so it would be a waste of time designing it. However, where the user is concientious enough to mount the sensor every time, it would be a good idea.

If a glass ceramic hotplate is used the boil dry sensor could be incorporated in the hotplate so that it senses the increase in temperature of the ceramic when a utensil boils dry and this would be the way to go. Similarly so for an induction type hotplate.

I've noticed. Are you EVER going to grow up? ;-)

1843? ;-)

--
Greed is the root of all eBay.

Ah. I guess most of us have projects floating at the back of our minds, some of them likely to be really useful. But we never get around to actually making them.