rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Mar 8, 2007 16:52:14 GMT -8
Gary, I though I would post my thoughts on your forum. Perhaps others are working on a similar project. I have a water level sensing circuit I use at my cabin (which has only a cistern) which indicates by way of led's, 1/4 level, 1/2 level, 3/4 level, and full. It works fine but I am trying to modify the circuit to indicate 1/4 level with a flashing led and an audible alarm, which might run on for a few minutes. The idea is that I may not see the indicator light, but would hear the low level alarm or buzzer. I am trying to design a 1-shot 555 timer circuit that would be triggered by the 1/4 level sensor going low, that is , open. The timer would allow the buzzer to operate for a minute or two, then stop. Currently I use a p type transistor which, when the base is low , turns on and lights up the 1/4 level led. I would like it somehow to turn on the 1-shot 555 timer. I don't want you or other readers to design it for me. I just would like some suggestions that I can work on alone. Perhaps there are logic circuits that would work better. Thanks, Richard
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Mar 31, 2007 6:16:06 GMT -8
Gary and all visitors. Since my last posting I have been working on a water level monitoring circuit with my son and have come up with a scheme that shows great promise. It uses a 741 op amp as a voltage follower (to give 5 volt supply from a 6 volt battery). An N type transistor is used to trigger a 74LS00. When the water level drops low, the transistor turns off, triggering the 74LS00. The 74LS00 provides a single short duration pulse which starts a 555 timer one shot , set for a given time period. The 555 timer drives a buzzer. The upshot of our circuit is that low water gives both a visual alert via an led and sound alert via the piezoelectric buzzer. Our circuit could easily be modified to give alert of other situations besides water level. It could alert you to light levels, sound levels, etc. I would be glad to share our ideas with anyone interested. Richard
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Post by Gary Lecomte on Mar 31, 2007 8:53:07 GMT -8
Both of these Ideas are really quite Simple to do, But I really haven't had many persons needing this. So I haven't bothered to do an article on it.
The only article I did post, uses an AC Signal, Which is Definately Preferrable over a DC signal.
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Apr 1, 2007 20:32:05 GMT -8
Well Gary, It is one thing to find a circuit someone else has designed, build it , and make it work. It is also something else, particularly if your are a hobbist and not a trained engineer, to take an idea, design it from scratch, and make it work. You have to intimately understand how a component works in the circuit in relation to all the components involved. It requires using a breadboard, circuit simulators, and a serious look into data sheets. As mentor, I really think you should be supportive of anyone having application idea, no matter how simple it might appear. You never know. Many simple ideas have ended up in patent form and resulting in riches for the designer. Richard Meyn
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Post by Gary Lecomte on Apr 2, 2007 6:33:35 GMT -8
Actually I Am Very Supportive of Experimentors.
But I get about 30 emails every day, with about 5 of these from persons Requesting Unique Designs or Application.
Unfortunately I am Only one Person and there is only 24 hours in a day for me to deal with all this. Presently I Spend about 12 Hours Every Day, 7 Days a Week trying to help people as well as design new projects for my site.
However because of TIME, I try to deal with the projects that are of MOST Interest to the people.
Now, If you want My Real Opinion of your circuit, Email a Schematic to me and I'll look at it. However I don't have any of the 74LS00 to actually Duplicate or test it. Actually I Don't stock any of the 74xx Series of IC's
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Apr 2, 2007 17:18:13 GMT -8
Keep up the good work Gary. Actually, I don't need help at this time. I thought there might be a few out there with similar interests to mine and a few that might want to exchange ideas. I find it difficult to believe there are no other experimenters interested in electronic sensing, alternative energy, and the like. I won't bother you with needless questions, unless I am really having a problem. Regards, Richard Meyn
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Post by Gary Lecomte on Apr 3, 2007 5:44:22 GMT -8
There Probably are some people that are interested in that. The Problem is to FIND Them.
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Apr 20, 2007 20:20:38 GMT -8
I've noticed quite a few folks have reviewed my on-going design project. Well, I'm pleased to report that , at last, I have a design that not only simulates well with Pspice, but also works as planned when wired up. I had problems with the resistance of water, but found that by boosting the voltage to 9Volts all problems ceased. I now have a circuit that gives me indication of 1/4, 1/2, 3/4, and full water levels and warns me by way of a buzzer when the level falls below 1/4 pool. The circuit uses a quad digital switch, and 741 op amp as a buffer, a quad input nand gate, a 555 timer, 2 transistors (one NPN and one PNP), a piezo buzzer, and 4 leds and a couple of timing capacitors. The circuit is simple with a small number of components, and not very expensive to build. I would be happy to share my circuit with anyone who is interested. Just ask and provide me with an email address. Richard L. Meyn
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Post by lamazoid on Apr 22, 2007 7:06:59 GMT -8
Why not to post it here?
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Apr 22, 2007 7:55:39 GMT -8
Yes, I will. I'm pleased someone is interested in my project. I'm presently working on formatting the schematic so that it is readable. It is drawn with PC Schematic express. I've had trouble creating a quality drawing in bmp or gif format. Richard
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Post by lamazoid on Apr 24, 2007 12:15:12 GMT -8
Are you still having trouble? I don't know about your software, but most others offer an "export" feature for graphic format. Either you can use "print screen" button and paste it into paint or something....
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Apr 24, 2007 12:51:21 GMT -8
I have two problems. (1). I can use screen capture and create a paint file. But I'm not happy with the resolution. It pixelates out and gives a fuzzy image to the receiver of the file. (2). I emailed Gary on how to insert a picture into the forum. The help section says nothing. I suspect I know how it's done. I just need Gary, the moderator, to confirm it. Please be patient, as my work load is substantial and this electronic business is just a hobby. Richard
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Post by lamazoid on Apr 24, 2007 23:33:59 GMT -8
I think you don't need to disturb Gary on that ))) There is special tag to insert images on forum - (img) image path (/img) . In this example you should replace rounded brakes "(" and ")" with squared "[" and "]". Image path is full URL. To store image you can use any free service like imageshack.us
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rmeyn
Full Member
My primary interests are electronics, sailing, bowling, and camping
Posts: 163
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Post by rmeyn on Apr 25, 2007 4:54:26 GMT -8
Yes, I suspected I would have to provide an img tag and a URL. I've done quite a bit of programing in HTML. I will set up a folder on my business website and insert the image there. My schematic software (Express Schematic ) does a pretty good job of exporting a graphic image, if it is set up correctly. I will do this as soon as I can. Richard
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Post by Gary Lecomte on Apr 25, 2007 6:13:12 GMT -8
rmeyn, Email me the Schematic. I'll fix the Quality and Post it here for you.
Gary
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