The Link Telephone Intercom

[Cory D]

On the project "The Link Telephone Intercom - Every Home Should Have One"...I am a little lost here. Example: On the parts list listed below, R3 is listed as 4K7. No 4K7 exists that I could find and was wondering if this was a typo meaning 47K? Same with the trimpot...however, the trimpot can be set to 47K or 4.7K...don't know what it is. I want to run this project with a 12v battery...where would the power be applied on this schematic? Will I still need the Tx? If so...no 1K/8R with a center tap 1K is listed no where. I have seen some Tx's list like this 1:8 8K etc...but not like it's listed in your parts list. I can't proceed without this info....please help!

 

[Cory D]

The other project I have an interest in building is the "The Link A2B+1 (DTMF Version)." It has the same parts issue with resistors; 4K7. Are they 47K or 4.7K. I cannot find a listing for them as 4K7. Again, I want to use a 12v battery supply with this project and not AC. I do see where I can place the 12v supply into this system. DO I need to use a 12v to 12v regulator? Thanks again

 

[liquibyte]

On the project "The Link Telephone Intercom - Every Home Should Have One"...I am a little lost here. Example: On the parts list listed below, R3 is listed as 4K7. No 4K7 exists that I could find and was wondering if this was a typo meaning 47K? Same with the trimpot...however, the trimpot can be set to 47K or 4.7K...don't know what it is.

The 'K' denotes the decimal point. 4K7 would be 4.7K.  I think that the trend was started in Europe but I actually like the idea, it stands out more than '.' does.

I want to run this project with a 12v battery...where would the power be applied on this schematic? Will I still need the Tx? If so...no 1K/8R with a center tap 1K is listed no where. I have seen some Tx's list like this 1:8 8K etc...but not like it's listed in your parts list. I can't proceed without this info....please help!

This is a pretty crappy schematic IMHO, the resistor symbol is very odd to say the least.  Anywhere you see +12V is the 12 volt positive input and the ground symbol is what would be the negative side of your battery.  Someone else may have to chime in about the 1K/8R thing, I'm not sure what kind of transformer this is referring to.

Slow down sparky.  Link to the projects so that others can help you.  See my paragraph above about the inputs.

 

[liquibyte]

I found out what that transformer is.  It refers to a 1K 8ohm audio transformer.

 

[Cory D]

liquibyte, thanks for the guidance. I am a novice at this...LOL...as you can tell. I'm not sure how this project will turn out...we'll and I'll post my results. There is another project I was going to tackle as well...but I'm finding out the a decoder IC "MC45436 DTMF" does not come up anywhere in the datasheets or anywhere else. SO I'm wondering if the M8870 DTMF IC can replace it. The other was the CD 4515B decoder. These items are for the "The Link A2B+1" by Austin Hellier. Since I cannot find the Datasheet for the MC45436...I have nothing to compare the M8870 to other than the interface...and I'm not to sure about that...LOL
Also, if you could look at that schematic, the resistors R8 & R9 show arrows and no connection. Is this to ground? No ground symbol is shown...so I'm not sure where they connect! Can you help, PLEASE? Thanks

Still Learning....

 

[liquibyte]

liquibyte, thanks for the guidance. I am a novice at this...LOL...as you can tell. I'm not sure how this project will turn out...we'll and I'll post my results. There is another project I was going to tackle as well...but I'm finding out the a decoder IC "MC45436 DTMF" does not come up anywhere in the datasheets or anywhere else. SO I'm wondering if the M8870 DTMF IC can replace it. The other was the CD 4515B decoder. These items are for the "The Link A2B+1" by Austin Hellier. Since I cannot find the Datasheet for the MC45436...I have nothing to compare the M8870 to other than the interface...and I'm not to sure about that...LOL

I think this might be the datasheet for the 45436 and 4515B.  Also have a look through the DTMF chips on Digikey.

Also, if you could look at that schematic, the resistors R8 & R9 show arrows and no connection. Is this to ground? No ground symbol is shown...so I'm not sure where they connect! Can you help, PLEASE? Thanks

The '1' and '2' by the arrows give a hint, look at IC3.  Make sure you check with the datasheet though.  I find that it sometimes helps to redo the schematic so you understand the connections.  I never liked using ground and power symbols, it makes the eye jump around too much in my opinion.

Still Learning....

So are we all.  This is a journey without end, enjoy it.

 

[Cory D]

I have ordered the components I need for this project. You are sure right on the "Journey" part...LOL. I have Liverwire software ordered...the demo version really needs to have a little more thought behind its purpose though to sell their product...but I have discovered that the optocoupler 4N25 is different than what is on the schematic. I have just learned that what is shown on the schematic is a MOC8108 6 pin OPTOCOUPLER FOR POWER SUPPLY APPLICATIONS! The base is not connected on the schematic (OC1-OC3) and the datasheet for the MOC8101 is identical to the schematic. The 4N25 is connected (pin 6) on the datasheet. At your guidance, I am doing just that...looking closer at the schematic. LOL...NOW...I wonder where the 6 pin connects! I'm sorry...that's the schematic for the "The Link Telephone Intercom"....like the subject bar. I have a few MOC8101s but not sure if I should use them on my bread board to see what happens...LOL. That's the reason for the Livewire Software. I can try the circuit there first before burning down my bread board ;-)
Is there a link to the creator of this schematic or system? I've tried to contact Austin Hellier...but no way to contact them/him. Cause I'd be throwing this at him/them instead of here. Any Ideas, Liquibyte? Thanks

 

[liquibyte]

I don't think you'll melt your breadboard with a low voltage circuit if you're careful enough to hook everything up right.  I have done it in the past by reversing things that I shouldn't have.  Watch the polarity on your caps, shit will scare you half to death when they explode.  ;D

I honestly don't know how to contact anyone that has projects listed here other than what the project page itself has to say about it.  Some of the projects here go way back.

 

[Cory D]

LOL...I will do that...with safety glass and a fire suit ;-). Yeah...the Austin Hellier web page is no help. When I put it all together and plug it in....YIKES....I'll post to let you know how it....WENT! I will also list any changes, if made, and probably will, to get it to work. Anyone else who has any ideas...please post. Thanks again, Liquibyte.

 

[Cory D]

Hi Liquibyte, stuck on another problem...please look at the schematic again and help me if you can. The 556 timer chip shows #7 leg to ground. If you look, the number 7 shows a connection from the emitter side of Q5, ok? But to the right of it shows another "Clear Connection" then connected to the line that connects to #3 leg of IC2 (Decoder Chip). Looking at the other "Clear Connects" around the schematic...concerning the ICs either shows a connect or just a line connect (With or Without a Black or Clear connection indicator). So now I'm not sure which is the correct connection of #7! Now since the line closest to #7 shows a connection to emitter line to Q5, and also shows grounded (0v-). Can I assume that it is #7...if so...then what is the connection to the right?  :-\  Thanks

 

[liquibyte]

This is a rather incomplete project in my opinion.  For one thing, I can't find D7 in the schematic so I leave it to you as an exercise to figure out where they meant it to go.  R10 is shown in the schematic as blank.  I had to place all the other parts to figure out where it went.  I did a quick schematic in Eagle using the basic parts or, in the case of Q6, their equivalent.  Also, the 556 in Eagle does not look like the one in the original schematic so the connections ended up resembling spaghetti.  My suggestion would be to rearrange the components until you have something you can work with and understand better.  Maybe this will help?

If you right click the signal line in the schematic and select show, all of the corresponding connections will "light up".

link_phone.zip

 

[Cory D]

I did notice the missing diode, D7, too. So the clear connection is a "Blank" connection then? Makes sense...however...it sucks too on this schematic. I did receive my software "Livewire" yesterday and will use it today and see how it goes. Eagle is a similar software program like Livewire? I so much appreciate your insight and help, my friend. I'm learning a lot...LOL! I hope this helps other people following these postings. If anyone has any input, please add your thoughts. I am a newbie in electronics and I'm finding it exciting, challenging, and the frustration...well, I won't post my feeling on the frustrations  ;D
Liquibyte, is there a way we can post any corrections (schematic Corrections) though this community or website so that when we come across poorly designed schematics or info, to pass along to anyone who joins, "Like Me," don't beat their head against the wall trying to figure it out. For me, its challenging just to get the parts found and arranged on a breadboard, let alone having to find things wrong, not shown, etc. I know no one learns anything without mistakes, research, asking questions, etc. But it would be a little easer to have a downloaded project that is working with minimal guesswork. Thanks again, Liquibyte, for your continuous help and in a timely manner!

 

[liquibyte]

Corrections go through the site admin.  My suggestion would be to have a working device that you've thoroughly vetted with schematic and board files as a download and pictures of both of those in addition to the completed device (source code too if appropriate).  Finished and checked gerber files are a nice touch so that anyone wanting to just make boards can do so with minimal work.  You'll find that not a lot of people use the same CAD program so even if you have a corrected and working version, the program you use won't work for everyone without translating the files from one program to the other which is why I recommend image exports.  A PDF would probably be acceptable as well.

Eagle seems to be fairly ubiquitous amongst hobbyists and is what I use for now because I'm used to it and it runs natively in Linux.  The big issue with it is that you're limited on board dimensions and restricted to two layers for the free version.  This usually isn't much of an issue until you realize it is and by then you'll know what you need to get things more in line with your needs.  You'll find others here use something completely different.

KiCAD is an open source alternative but needs real work to catch up with the big players in my opinion.  Diptrace is another popular alternative.  Altium purports to be coming out with a free version for hobby use but I have no experience with it.  I also don't have any experience with Livewire but it looks like it may do the job just fine.

I'm having trouble understanding what you mean by "So the clear connection is a "Blank" connection".  Wires with a "dot" where they cross are connected.  Wires that don't have the "dot" do not connect.

 

[Cory D]

  I've just started using Livewire so I don't know the software very well yet. In order to design a circuit board, you have to use PCB Wizard3 to make that happen which sucks really. I also found that you cannot convert your schematic to "Art-work" showing your design as it would look on a PCB with the components in place. The Livewire Demo version shows that...not the hobbyist version...it says you have to get the "Upgraded" version...LOL...another word for "More Money!"
  Anyway, I also found that the ICs pins are not labeled as it shows on the Datasheet. Is this normal for these software programs. For instance: On a 4017B decade counter, it shows vDD or vDO as pin 16 and vSS as pin 8. The Livewire software doesn't show that. They show Q0 - Q09 then EN and R on the diagram of the chip. Am I to "ASSUME" that EN is the Clock Enable/Inhibit (Pin 13) and R for Reset (pin 15)? I've looked on then internet for that past 2 hrs finding nothing on EN or R on an IC. LOL...I dumped the rest of my coffee out...in frustration and took a break before typing this. I've even looked on their (Livewire) website for info...nothing. Is this one of those Electronic Eng/Tech's community secrets?  LOL.
  What I mean, for the lack of terminology, clear connects are the circles or terminals that is not connected "O". The other is a connection, of course the black dot showing a line connection/intersecting. I did see what you're talking about on the chip showing pin 15 & 13 with "O". Same as on the 556 pin 10.
  I did want to ask and its slipped past me the past few posts, I'm using a +12VDC power source; to the right of Q6 shows ground OV- and +12V. Would this be the power source connection? Because at the bottom, it shows +12V & OV- ground (pin 8 of 4017B).

 

[liquibyte]

In the schematic part of the program, the pins for chips are usually labelled with the pin number and only sometimes the function of the pin.  So, yes, this is kind of a engineering thing you have to get used to.  I usually have the datasheet close by for whatever part I'm working with at the time.  In the board part of the program, pin numbers aren't shown but it's really not necessary because the "ratsnest" shows the connections once the schematic is complete.  As for the part not resembling the datasheet, that's fairly usual.  For instance, op amps are always show as a triangle on its side.  This is the universal symbol for op amps and convention dictates that they are always shown this way on schematics.  Once you get to the board side of things, the pin numbers are never shown but the part designator and name usually are.  I'm basically not familiar with anything other than Eagle so I can't comment on how the part libraries are for other programs.  If at this point, you think this is fun, wait until you run into parts that have the same part numbering but differing pinouts.  Transistors can really trip you up there as I learned recently.  Slow down and take your time as any program with this kind of complexity can be a real discouragement if you let it.  I could get into the programming side of things about how the programs generally work as far as layers go but that'd just bore you and would not be useful as an exercise.  Let's just say that by default, the ratsnest is a special signal layer.  You need to get your money back on the Livewire thing if you can't do boards with it without paying extra, that's just deceptive in my opinion.  It's just not worth it considering you can download free programs that do both.  Get a copy of Eagle and try it out.  I would bet there are nth more tutorials out there for it too.

I can help you with Eagle, I can't with Livewire other than in a general sense.  For examples of some of what I've been talking about, see the screenshot of a circuit I'm currently redoing the board on.

 

[Cory D]

I've downloaded the Eagle software...Wow is all I have to say right now! What a library! LOL...now to get use to using it! It does everything and WAY more than Livewire can do with PCB Wizard3...I'm glad I didn't spend the money for it. I did with Livewire, though. It's going to get some getting use to now. Thanks Liquibyte for the info! ;-)

 

[liquibyte]

Just remember to verify the footprints from the parts in the libraries to the datasheet of the part you're going to be using, not only for pin spacing but also pinouts on chips and such.  Don't be afraid to try the other programs out too.  Sometimes you'll find one that better fits your work flow.  Diptrace seems to be popular in that regard.

 

[Cory D]

The Newbie has struck again...LOL...oh, that's me! I have a question...for the lack of knowledge of abbreviations, what does "+ve", "-ve", "MR", "EN", and "R"? I think the "R" means Reset. A friend told me I can find these abbreviations in a book called "Ugly's Book of Electronics" or something like that. Thanks!

 

[Cory D]

I have a question...for the lack of knowledge of abbreviations, what does "+ve", "-ve", "MR", "EN", and "R"? I think the "R" means Reset. Well...I have searched and to no avail...have found what these abbreviations mean. I know EN means "Enable" and MR means Master Ringer or Master Ringer Circuit (MRC), but the other two...no such luck! Anyone have any idea...I hate to guess! HELP!!!