[David_AVD]

I'm designing a PCB to control a prop telephone. It will be able to ring a standard phone (no mods required), detect the off-hook condition and play audio through the handset.

The micro will be an Arduino Nano, mainly because they are cheap and programmable by anyone with a PC and a micro USB cable.

The audio is handled by a JQ6500-16P module. These are cheap and have 16Mb (2MB) of on-board flash so no SD card is required. That's enough room for plenty of short mono voice phases and maybe some dial tones, etc. A micro USB cable is used to add the audio files.

It also has a trigger input that can also supply 5V or 12V for a PIR, etc.

I'm not sure what else would be useful. Maybe an output that activates for the entire sequence to feature lighting can be triggered?

 

[halstaff]

Sounds interesting. Looking forward to seeing this.

 

[toozie21]

I need one of these for my Christmas display so santa can call the kids . Absolutely keep us posted on this!!

 

[David_AVD]

The schematic and PCB layout are about 60% done now. I'll post a 3D render later.

I've been testing the audio module and the only annoyance so far is that there's no serial stop command. You can pause playback, but not stop it. One workaround is to use the sleep command as it does stop playback but doesn't add any noticeable delay to the next play command.

 

[JeffHaas]

If that module doesn't work for you, try the Catalex MP3 board. I've been using it for some projects and it works great. Arduino code is available.
http://www.dx.com/p/uart-control-se...o-avr-arm-pic-blue-silver-342439#.VkAZg-JcK4I

 

[David_AVD]

Yeah, I have some of those boards (and they work ok), but like the form factor of the JQ6500 better for this project.

 

[toozie21]

The schematic and PCB layout are about 60% done now. I'll post a 3D render later.

I've been testing the audio module and the only annoyance so far is that there's no serial stop command. You can pause playback, but not stop it. One workaround is to use the sleep command as it does stop playback but doesn't add any noticeable delay to the next play command.

Nice, this will be fun to follow.

Are you able to pause the audio and then issue a restart command? I don't know what happens on a restart, but since it is only playing audio, I would think it would just sit there happily.

 

[David_AVD]

There is a reset command, but I've seen mention that you should wait 500ms after a reset. With the sleep command, I can tell it to play straight away.

I had already designed and made a phone ringer years ago, so that part of the new board will be the same except mostly surface mount.

Last night I patched in the speaker output of the JQ6500 audio module to the primary winding of the ringer's output transformer. The audio through the telephone's earpiece is more than loud enough.

Speaking of audio level, I will put a pair of tact buttons on the PCB for VOL+ and VOL-. The module seems to remember the last level set.

 

[Lightman]

I need one of these for my Christmas display so santa can call the kids . Absolutely keep us posted on this!!

Hey Toozie... don't forget DanoNJ's Christmas phone...
http://diychristmas.org/vb1/showthread.php?2462-Talk-to-Santa-prop&highlight=santa+phone

But not to take away from David's version. Its cool you will be ringing the actual phone...very cool. Kids will love it.

Years ago I built a stage prop to ring a real phone since techie's could never get it in sync with actor. I used an SX micro controller and step up transformer...as it had to ring the old Ma Bell type phones too. It had 3 different ring patterns and would stop ringing when actor picked up receiver. But it didnt have any voice in receiver.

I can't wait to see your implementation David. Keep us posted...

 

[David_AVD]

Here's a 3D render of the nearly completed board. I don't have step files for some of connectors.

 

[toozie21]

Hey Toozie... don't forget DanoNJ's Christmas phone...
http://diychristmas.org/vb1/showthread.php?2462-Talk-to-Santa-prop&highlight=santa+phone

But not to take away from David's version. Its cool you will be ringing the actual phone...very cool. Kids will love it.

Years ago I built a stage prop to ring a real phone since techie's could never get it in sync with actor. I used an SX micro controller and step up transformer...as it had to ring the old Ma Bell type phones too. It had 3 different ring patterns and would stop ringing when actor picked up receiver. But it didnt have any voice in receiver.

I can't wait to see your implementation David. Keep us posted...

Oh, don't worry, I definitely remember that. A small custom board designed for this task in mind was somewhat interesting to me. At some point I am going to get something phone oriented outside, so I am just happy to see others thinking through some of it as well .

Here's a 3D render of the nearly completed board. I don't have step files for some of connectors.

Looks good. What are you expecting the overall cost to roughly be on it? Also, is that transformer there for coupling audio into the phone line, or are you running AC to your board and converting down?

 

[David_AVD]

The board runs from 12V DC. The transformer is to generate the ring voltage at the correct frequency so that the bells ring properly.

I haven't worked out the cost yet.

 

[djgra79]

Following with interest, as I do with most of your little projects

 

[toozie21]

The board runs from 12V DC. The transformer is to generate the ring voltage at the correct frequency so that the bells ring properly.

I haven't worked out the cost yet.

Ah, didn't think about the ringer, I assume those need minimal current?

 

[David_AVD]

The current is low so the 3VA transformer is more than enough for the job.

 

[toozie21]

The current is low so the 3VA transformer is more than enough for the job.

Very cool. Have you breadboarded this all yet, or are jumping into your design (since the hardware is pretty straightforward)?

 

[David_AVD]

I've done the telephone ringer twice before, so that's straightforward. I tested the mp3 module audio output with the existing ringer so that's sorted.

The rest of it is quite simple. I design a lot of boards; this one is # 975. That's not to say I don't make mistakes but usually they are minor.

This is the first time I've used an Arduino in a design. Usually I use bare PIC or AVR chips.

I've added 2 small trimpots to the design now. Might be useful for adjustable times.

 

[David_AVD]

Here's the latest 3D render. I've also added an open collector output to trigger another prop.

 

[toozie21]

Here's the latest 3D render. I've also added an open collector output to trigger another prop.

Looking good. How long of phrases are you expecting to be able to do?

 

[David_AVD]

The audio board has a 16Mb (2MB) FLASH memory. As a test I loaded an mp3 track that was 3:42 long and encoded as 64kbps. That filled most of the FLASH and the quality was more than good enough.

I've revised the board again to add a set of 5 option jumpers under the Arduino. They'll likely be too tall for actual jumper headers, so may just be solder pads.

I also changed the trigger input to include an optocoupler so that you can use a voltage trigger as well as contact trigger.