| Electronics > Beginners |
| Need help turning old payphone into dial-an-mp3 display |
| << < (6/9) > >> |
| skarecrow:
--- Quote from: Beamin on September 04, 2017, 12:50:37 pm ---You realize the key pad doesn't put out the tones right? Also the key pad is hooked up in a matrix where pressing a button doesn't just switch on a wire it makes combinations which have to be sorted out. I don't know where the pi would have separate audio out and audio in jacks that you could just plug into. It has one jack that's shared with something else like composite video. Accessing this might require a program through python. I found personally it was much easier to use the Arduino and C compiler to do things then the pi. Plus I think C is more useful if you are going to spend your effort and time. --- End quote --- That's the exact reason I recommended NOT scrapping the guts of the phone. The keypad only works because of the rest of the "guts" of the phone. The end result is a pair of audio tones that can be fed into the pi through audio. I thought they had an audio input, but if they don't you can use a usb sound card plugged into one of the empty usb slots to solve that problem. Sent from my XT1565 using Tapatalk |
| station240:
Should simply be a case of powering the phone and getting signals in and out of the line. power in. dial tones out. voice signals in (music) Not sure if this payphone uses DTMF (google it) signals, or some form of digital. Certainly possible to make all this work without having to open up the phone. Thought it may still need that done to clean it. |
| Towger:
--- Quote from: skarecrow on September 03, 2017, 07:13:34 pm ---Are handset speakers 8ohm? For some reason I thought they were 32. --- End quote --- Off the top of my head I think old phone hansets might be 600ohms. |
| Beamin:
--- Quote from: skarecrow on September 03, 2017, 07:13:34 pm --- --- Quote from: Towger on September 03, 2017, 06:06:39 pm ---There is no need to connect to a PABX. The guts of the phone can be scrapped. The pi has stereo audio out, just a matter of connecting it up to a cheap 8ohm speaker in the handset etc. --- End quote --- --- Quote from: skarecrow on September 03, 2017, 07:13:34 pm --- The guts CAN be scrapped, --- End quote --- --- Quote from: skarecrow on September 03, 2017, 07:13:34 pm --- That's the exact reason I recommended NOT scrapping the guts of the phone. The keypad only works because of the rest of the "guts" of the phone. --- End quote --- So "CAN" they be scrapped or not? I'm trying to work out how to do this for another project similar to the OP but I don't understand how the circuit to the key pad can be optional i.e. they can be scrapped but at the same time they shouldn't be scrapped. Also why would you put another speaker in the handset? I imagine it would be hard and take some modification to fit another speaker into that small shell and at least some soldering. --- Quote from: skarecrow on September 03, 2017, 07:13:34 pm --- The software can turn the dtmf tones it receives through the pi's audio input and navigate the system, just as if you had dialed into a real pbx. Are handset speakers 8ohm? For some reason I thought they were 32. Sent from my XT1565 using Tapatalk --- End quote --- I have a pi3b: Where can you connect audio in? I would like to use it as a sound card. They make USB soundcards? What would use such a thing so I know where to find one? Also how do you match the impedance from the phones DTMF into the pi? Wouldn't it just overload without some sort of matching transformer? Do the USB sound cards have line level in or mic in? I have wanted to make a VLF radio from one and if its that simple it should be doable. --- End quote --- |
| Funvoyager:
Hi everybody. OP here. I appreciate all the interest and debate on the fine details of this project. It looks like there are a number of ways this could be done and that I'll need to hire a pro to oversee this project, recommend the final list of supplies, etc., and triage the various simple to complex solutions based on budget and level of interest and ability with the group Regarding the kickstarter idea, that's a really good suggestion or maybe gofundme ?? I could describe the project without getting too technical but mention the requirements to demonstrate the scope of complexity and need for help. If it's not funded at the highest level then maybe a low tech backup plan could be employed. I'm hopeful because even though I'm not knowledgeable of the different technical solutions being discussed, I'm confident that, at a minimum, I could make the phone play a random or continuous play audio of something that is activated by lifting the receiver - or maybe it constantly is on and plays to the ear piece and I could try to recruit people interested in the potential to upgrade it to how ever fancy and cool it actually could be Problems I'm working on now are purely mechanical in the meantime: 1) finding a key to open phone or using a hacksaw blade ?? To saw through lock. This thing is a tank. 2) getting a piece of plywood to attach to drywall to hang phone. It's way heavier than I imagined and want to make sure it's secure to the wall. I can't just use molly bolts, I'm going to have to distribute the load to support this phone. 3) figure out how to unscrew handset mouth and earpiece. It's either tight or glued or something. That way I can have access to handset insides in case I end up going low tech and put an actual mp3 player or speaker inside the handset that is connected to a charge cable threaded through the tube into phone, then drill hole through case and thread charge cable to an inconspicuous outlet so out stays on 24/7 I'm pretty excited at the low to high tech solutions to this. Money doesn't seem to be a big barrier unless the parts are really expensive. I'm thinking that the money is needed for labor for each level of expertise in consulting and oversight I've searched for clubs and makerspace ?? places in the DC area and am surprised there isn't a club or group that is already in place. Maybe dc is less technical compared to other places or I'm not advertising in the right circles. I miss the days when radio shack was more prevalent I'm going to get some bids from upwork to estimate labor costs. My guess is that it's a pretty specialized job bc it incorporates new and technology and programming like raspberry pi and also an understanding of obsolete technology and old school electronics. I imagine that is an elite group that has that full range of expertise I'll keep you all posted. Thanks for the ideas and encouragement! John |
| Navigation |
| Message Index |
| Next page |
| Previous page |