Project Proposal: Answering Machine
rokicki
Posts: 1,000
Here's a project that I think the Prop is totally perfect for.
I want to replace the cheap electronic answering machines I'm currently using, which are so frustrating, with a nice prop-based one, that stores the messages and announcements on an SD card.
Something with a small but clear screen (a small phone LCD would be perfect). Something that tells you what's happening, and gives you clear instructions on how to do what you want (like, let me pick up the phone, you stupid piece of electronic junk).
But it would be nice to have the messages organized by date, by caller id and time, to be able to save messages to the PC (via the SD card), and just in general have a premium answering machine rather than a cheap piece of junk.
There are probably premanufactured modules that take care of interfacing with the phone lines (to manage the ring voltage, to provide the necessary loading and unloading and hooking and other signaling, and to meet the requirements of the phone company). Does anyone know anything about this?
I want to replace the cheap electronic answering machines I'm currently using, which are so frustrating, with a nice prop-based one, that stores the messages and announcements on an SD card.
Something with a small but clear screen (a small phone LCD would be perfect). Something that tells you what's happening, and gives you clear instructions on how to do what you want (like, let me pick up the phone, you stupid piece of electronic junk).
But it would be nice to have the messages organized by date, by caller id and time, to be able to save messages to the PC (via the SD card), and just in general have a premium answering machine rather than a cheap piece of junk.
There are probably premanufactured modules that take care of interfacing with the phone lines (to manage the ring voltage, to provide the necessary loading and unloading and hooking and other signaling, and to meet the requirements of the phone company). Does anyone know anything about this?
Comments
http://www.sparkfun.com/commerce/product_info.php?products_id=8600
I also have 3D GUI elements for it like buttons and list boxes, etc....
Check this for a demo: http://www.youtube.com/watch?v=YalcMqkdHEU
Cluso99 should be able to answer any questions on phone line interface.
I'm not sure, but you could probably get away with letting the phone company provide power assuming current required is not too high. I've heard they don't like to be in the power company business, but phone lines have (or did have?) 48VDC for the old style hand-sets.
How about adding a networking module which emails the wav files to my email address from the SD during it's downtime?
OBC
FAT32/16 File System Driver :
http://forums.parallax.com/showthread.php?t=122991&highlight=fat32
I think the important thing is to establish the basic core functionality. Things like:
1) ring detection
2) answering (i.e., phone off and on hook)
3) playing wave file (or other audio) over phone line. I think it would be useful to be able to patch in any audio as part of the hardware.
4) recording audio from the phone line
5) recognizing touch tones
6) caller id
All other things can be add ons. It could be a nice open package allowing people to add whatever displays, UIs, network capabilities, etc. that they want.
At least for me, it's the core capability similar to what I listed above that is outside what I know how to do.
In the past, I figured it might be worth it to tap into the capabilities of a voice modem to do this - with external control (even if it was built into the case) handling the UI, etc.
I currently have a box that sends caller id information through a serial port to a PC that I have "running" my apartment. It compares the caller id with a database and makes audio announcements throughout the apartment telling me who is calling. It's also displayed on little LCDs mounted in different locations.
This is the kind of capability that would be really easy to add to a core system and the information could be sent out through serial/USB, RS485, ethernet, etc.
http://cmapspublic3.ihmc.us/rid=1HLGXHKR2-2560LQ0-MR8/PropAnsweringMachine.cmap
That's the case here, too, although it often comes bundled with "service plans". However, even those who don't have it can access the last number a call came from by dialing *69 for a per-instance charge.
-Phil
These days call screening is almost as important to me as anything else especially with ROBO-CALLS. Having an answering machine that would pick up for a few seconds and listen before answering would be valuable.
Filtering annoying calls (or forum posts by keywords?) without me getting involved would be useful.
Being able to program machine behavior would be the key attraction for me.
--Steve
We can dial 1471 to get the number of the last person to call. That is free, here. 1571 gets voicemail.
Cluso99 will prob be able to help with the DAA side of things. In the mean time check out this chip from Clare semi - CPC5620. Handles the line isolation, called ID and more, and runs from 3.3 volts. $5 from digikey in a SOIC32, and no scary magnetics
http://www.clare.com/home/pdfs.nsf/www/CPC5620_21_R04.pdf/$file/CPC5620_21_R04.pdf
Pitty as I have thrown my last pcbs and parts out some time ago that did music on hold. It would have been simple to connect to and I had approval for Australia, which means it would pass most places without retesting (NZ, most of EU, UK, except the US which used different testing although I am certain it would pass). Testing and certification cost ~$5K-10K but this was 10 years ago.
It did use an Etal small transformer and a MC68705J1? micro. I will dig a photo and post here later - remind me if I forget as I am extremely busy and will be for another week at least.
The isolation & approval is required as you do not want to fry a techo fixing the phone lines down the road - it happened a long time ago when someone accidentally connected mains to the phone line while a tech was working the lines.
I am not sure if anyone makes an approved isolation device these days. Years ago, they did but cost more than a 33K modem.
Anyway, I can certainly help as what you are trying to do is actually extremely simple from the phone line point of view.
That is why I would love to have a hate list. The 'phone is the second rudest thing in my house, it rings and demands that you leap at it before that vital call is lost forever. Even when there is a recording device curiosity drives you mental.
I am sure that I saw a thread (AVR) a while back allowing the ring to be driven from the vetting and the phone's to be muted so that it would only allow wanted, listed, numbers to disturb you
I don't understand why this feature (along with REAL rewind, not skip back) seems to be missing from modern answering machines. Having to listen AGAIN to a three-minute message to get the phone number, which is spewed out in 3 msec at the end of the message, shouldn't be necessary nowadays.
- Mark
After that, people should be able to develop whatever features they want to add to the core. For example, if you don't want playback on the device at all (everything sent to a PC (or emailed)) it's no problem - just don't add it. If you want a nice video-based UI, go ahead and add it.
If it stays modular, features can creep in and out as much as people want.
Many moons ago I purchased some Swedish units which were marketed as "fax converters". I wish I had bought more as they have been very useful and saved many $ in phone calls when testing modems etc. These had two RJ11 jacks and essentially simulated the phone exchange for testing purposes (voltage and dial tone generation etc). They ran off two 9 volt batteries
Such a device would be useful here for getting things up and running safely and legally. Perhaps there has been a kit in an electronics mag or somewhere.
http://www.radiolocman.com/shem/schematics.html?di=64371
Interesting site to look at is also:
http://www.rowetel.com/blog/
When are you in Sydney or Brisbane/GC next?
The rowetel stuff is particularly relevant to a potential job that needs internet access inside tractors for high accuracy GPS, in you guessed it -near Adelaide SA. Looks like a great 'fit' actually.
Those little FXO / FXS modules also look very useful. I'll find out some more about where they are approved, and how easy they would be to interface to the prop.
Thanks again
tubular
I'll need to visit both in the coming months. Brisbane first, more likely. I'll let you know as soon as I know. It would be good to catch up on all sorts of stuff
When I was a kid way before Parallax was even on the map, I built my own answering machine with discrete logic and lobotomized parts from other 'non functional' answering machines. It was a very fun and rewarding project to see something like that work.
By pure accident from the answering machine project, I came up with a little off-shoot circuit that was capable of answering the Phone before any of the other phones in the house rang. This was very handy as a teenager when I didn't want to disturb my parents or let them know that I was on the phone with some girlfriend or something.
Anyway I noticed that when the phone rings, the polarity reverses, however 'JUST' before it reverses it will pause for about 1/3 of a second at Zero volts. A crude Zero-cross detection circuit and a relay that clamps the line was all I needed to answer the phone before any of the other phones rang. Now, I'm not saying it is necessary to do anything like that, for an answering machine, but if you know what to look for in the telephone signal, it makes for relatively easy ring detection.
A similar detection can be made to detect when someone picks up the line, IF you design the answering machine with a higher off-hook impedance than any of the other phones in the house. This way you can set a voltage threshold and if the line signal falls below a pre-determined value then you know that someone else has picked up a phone.
Anyway, fun project, just thought I would give my two cents...
Another oddity was that Bell 103 (300 baud in the USA) was not permitted in European countries and Australia and NZ. All US modems up until 2400 V.22bis used the old Bell 103 to send answertone and start the handshake sequence. It was a far superior system to Europe, but that didn't stop Europe from saying it interfered with their phone systems and banned Bell 103 and effectively US modems.
Little did they know that all the alarm systems in use around the world including Europe, Australia & NZ were usng Bell 103. If they realised I am sure all their phone exchanges would have crashed LOL.