Automatic Phone Dialer

This is the second question like this in the past week. Is this homework? Anyway, any off-the-shelf home security system will do this. Radio Shack used to sell these; don't know if they still do, but you might check.

It would seem as though there should be guideline respecting what questions will be entertained by the group. Apparently the fact that this gentleman would like to "build it himself" riled you a bit. Just because something is already on the store shelves and can be had in a moment with a few key strokes does not mean that it would be of no benefit to build one.

I can buy an FM radio almost anywhere. But, you'll notice that FM radio kits still sell briskly. Perhaps all of these hobbyist are just morons for building what has already been built.

I notice you have posted here for a long time and seem to be well respected (judging from your number of "good answers"). I'll ask you then: is there no place for the "Technician class"? Is there no room here for those of us without degrees to learn from the rest of you? Should there be a flashing icon on each page that states "no hobbyist, no stupid questions (and if you aren't sure then it must be a stupid question)"? Maybe you can enlighten me.

Good answer, JScott13, excellent answer! That's what I call arrogance in the cross-hairs.

Sorry, I have to side with TVP45 on this one. The original post in no way indicates the desire to build an auto dialer from scratch - only that he wanted to incorporate one into another design. I think you have read more into the question than is warranted and were yourself riled by TVP's interpretation of the question. We often get posters who appear to be trying to reinvent the wheel simply because they don't know what is available on the market. This is not a crime and a gentle push in the right direction is never unkind. If the OP would have responded with "No, I'm sorry - I am looking for a kit or a circuit diagram for one of these" most of us will bend over backwards to find a source. TVP's response was neither arrogant or dismissive, and did not indicate in any way he considered the question stupid, but was offered in the true spirit of this forum. I believe all of us respect the innovation that can spring from the "Technician Class" and great patience has been shown on this forum trying to explain the subtle aspects of fundamental principles to lay-persons with well-formed questions. If the group had really thought the question to be "stupid", it probably would have just been ignored - or a truly scathing response would have been posted.

Are you enlightened?

Hardly enlightening.

Comments like: "This is the second question like this in the past week. Is this homework?" would do little to in the way of assistance or encouragement. It would seem as though I was not the only one who found this insulting.

I have been the recipient of the kind assistance you mention and am very grateful for it. I have also noticed that questions like "Should we answer stupid questions" take up a large percentage of space. I can't help but sense an elitist attitude when answers begin with chiding.

However, your assessment of my attitude towards this response was an accurate one. I also see, on further reflection that I may have read too much into the question.

Comments like: "This is the second question like this in the past week. Is this homework?" would do little to in the way of assistance or encouragement. It would seem as though I was not the only one who found this insulting.

The unfortunate reality is that there is substantial evidence to suggest that this web address is being passed around engineering and technical schools as a source for homework help. While no one here is against helping a student, many of the homework questions are not honestly presented as such and it is professionally irresponsible to provide easy answers to students. The same question popping up so soon is certainly a red flag. None-the-less, TVP45 indeed answered the question as he understood it, while providing a gentle nudge that if this were a homework question, perhaps the student should evaluate their academic integrity. It is not meant to be elitist, only to give pause.

As for a perfect example of the type of "stupid question" of subject in the thread you referenced, and a classic response, see here.

"I am working with the security system project as hobby.I want to buil a system which make a phone call to the specific number when it detect the thief.I don't know about phone,so please help me?"

CSM Engineer, I have a great deal of respect for you and your posts because you usually are spot on and have a high ratio of good answers, however the initial question was specifically about building a phone dialer for a hobby project. It seems the confusion was with the phone more than the workings of the dialer. I feel if TVP45 doesn't know the solution or doesn't understand the question, he shouldn't slam the door so hard. We all like to learn a little about technologies outside our specific arenas of expertise.

I still must disagree. My understanding of the initial question was about incorporating an auto dialer into a custom security system, not specifically building the dialer from scratch. The poster seems unaware that technology for this function already exists. TVP45 seems to share my understanding. That there are at least two others that understand the question differently indicates that it was a poorly-worded question. In that case, it is the OP's responsibility to post a clarification. TVP45 did not slam the door, merely commented on the frequency of this specific inquiry. It would take a very thin-skinned poster indeed to take that as a door slam. If you want to see a door slam, search for Sparkstation's recent response (just yesterday) to the poster requesting all dimensions for steel washers; that was classic!

It's called an auto-dialer (oddly enough) - I've used them extensively in remote installations to monitor operating parameters. If a parameter goes out of range, I get a call with the station number and a code telling me what parameter is out and if it is high or low. Very reliable. We also used to get them from Radio-Shack; I think Automation Direct also markets a relatively inexpensive version.

Is this what you are looking for?

http://www.protectedhome.com/search_results.asp?txtsearchParamTxt=&txtsearchParamCat=3&txtsearchParamType=ALL&iLevel=1&txtsearchParamMan=ALL&txtsearchParamVen=ALL&txtFromSearch=fromSearch&btnSearch.x=14&btnSearch.y=13

Hello Skeeter,

I like what I saw.

But using an existing phone line could pose it's own problem assuming the line is engaged while the movement is detected. Though this can be avoided by making the line dedicated to that service.

A fullproof will be to have the unit connected to a simple intercom circuit (Nevermind, this poser is for the manufacturer )

Cheers

ethobil

a complete schematic of a dialer system here:

http://users.tpg.com.au/users/talking/DialAlarm-1-Page1.html

Ramsey Electronics sells very inexpensive kits that you could use for this purpose. You should also check out Velleman Kits as well. There are a number of hobbyist sites that have schematics posted. A search under "schematics telephone control" or "schematics telephone dialer" might a good bet.

this also might be useful:

http://www.epanorama.net/circuits/teleinterface.html

You might base your design on this chip. Might be worth looking at:

http://www.nteinc.com/specs/1600to1699/pdf/nte1690.pdf

There are several commercially available alarm dialers. Your "hobby", so I don't get confused is to build a "security system". This dialer would be a part of that system. You can get one manufactured by Sensaphone from Aston, PA, USA. They have many models starting at around $400 US. Another is RACO systems. They, too have various models only more expensive. I think Radio Shack discontinued their line. These are all good units and very reliable. I have use them many times.

Several 'uptight' responses in the group of responses - why not simply ignore questions that rile you or that are considered trivial?

Ok, lets ditch all the is this a valid question or not and get back to what was being asked.

Yes it is true that most security systems have auto dialers but I get the impression you want something a little more complex than that.

Going back some 15 plus years I built a PC based home security system that utilized a sound-blaster card, a specialized interface card that could monitor 8 signals and a standard 1200 baud modem. The system was used to verbally annunciate things like the front gage being opened. It also had a series of motion detectors connected to it and when there was nobody at home it would dial a paging service and transmit an appropriate text message to my pager that would let me know what was going on.

Later on when mobile phones became more prevalent I modified the system to dial my mobile phone and then transmit a verbal message that was generated by the sound-blaster to let me know what was going on.

At the time there were numerous commercially available systems that had auto-dialers but none of them could do anything more than dial a dedicated security monitoring service and notify them that an intruder had been detected.

Unfortunately most of the security systems now available will not do much more than that so if you wish to do something more advanced like call your mobile phone an tell you what is going on then you are going to need to build it yourself.

The simplest answer is to purchase a voice capable modem and use that to do all the telephone system interfacing. You will need to write a program that can instruct the modem to dial a number and also a text to speech program to generate the audio input for the modem but it can be done relatively easily.

From what I gather you are interested in home automation and there are a few tricks that you may be interested to know. One of the big problems with home automation is trying to control devices that use mains power. Switching mains power is something that should be left to the people that understand what they are doing but there is a safe way you can work with mains power. What you do is use a Programmable Logic Controller PLC to do all the interfacing with the real world and switch thing on and off then link it to a PC that does the fancy things like verbal annunciation and voice response.

If you want to learn more about what is possible you can contact me using the CR4 mail system.

i am responding a little late but he goes if you build a dialer you need to know how a phone works first remember a phone has NO zero (0) 0=10 for digi pulse or (touch tone you have to observe polarity) and to seize the line if some one is on it at the time of your alarm after that you send a digital or audio signal to the remote location eg. telephone, cell, PC, then hangup it wood be so much simpler to buy a security alarm control and revers eng.

a phone dialler system is always built-in in a specified device. may I sugest for you to try to consider that the fact that it can be purchase so not to punish yourself in finding solutions that are already out in the market. try optex sysem