Electronics DIY Wireless RF Remote Control - It's Alive!

[Skylined]

My MP3 CD player didn't bring a remote control.
This player is always going to be inside my backpack as my old Discman used to be.
Having so many songs, a remote control is a great idea, so I don't have to get my backpack in front of me, unzip it, press the buttons until I hear the song I want, then zip it again and get it back on my back.

This player comes with the connections for a remote control, but I don't know how the remote control on this one works, it only has 4 terminals for like 6 buttons that its original remote control has.


So instead of that I was thinking about soldering some cables directly to the buttons on the player and wire them to momentary opened buttons that are going to be in a small box, like the ones used for car's alarms, and this box is going to be in one of my pockets of course!




The buttons are those little silver dots that appear on the pic.
They all have a common ground and I can take that ground directly from the base of the player, so that's 1 less cable coming from that PCB on the pic.
I'll run 5 cables down to the base of the player, Play/Pause, Stop, Next, Previous and Next Album, that's all I want.
At the base of the player I'll drill a hole and I'll put a PS/2 socket (5 buttons + common ground) where the remote is going to be plugged.


Help
Does anybody know any cable with 6 conductors(?) as thin as possible?

[The Savior]

Ethernet cable should do the trick, plus it's cheap.

[SanDmaN]

I think the reason there is only 4 pins for the 6 functions is because you can use the same pin twice, a bit like binary. Hopefully my little diagram will make sence.

pin 1 is the -ve / ground : X = button pressed : - = button unpressed.
Pins 1 2 3 4
G - - -
G X - -
G - X -
G - - X
G X X -
G X - X
G - X X
G X X X

the 1st combination is the remote @ default and the other 7 are combinations of when a button is pressed.

Now I have only just figured this out [if indeed it is correct] so dont flame me if I am wrong. At least I understand it

[Rod10k]

I know that my sony remote for my minidisc has four pins, it has 11 buttons and an LCD. iirc it uses resistors as a DAC. I assume that one pin is power, another ground, one serial data to LCD and the other analog button presses.

For this reason I would avoid just connecting power up to the headphone socket without scoping it out first. Idealy you would get hold of a remote and then reverse engineer it, however once you had that you might as well use the remote.

I don't see any problem with wiring directly to the front switches, you could even make it RF

Rod

[Skylined]

Is there anything thiner than an Ethernet cable?

Good one SanDmaN, but as Rod10k said, it's serial, this player also has a remote control that comes with a LCD.

As for RF, I don't want to add to many things to the player's ciricuit since this MP3 player seems to drain the batteries a lil bit fast.
If you already have any idea or link, post it please, and I'll take a look.

[mottl3y]

what about just plain ribbon cable, and rip off the number of threads you need. could paint it to be less ugmo

[Skylined]

A ribbon cable coming from my backpack to my pocket won't look nice.

Now I'll try RF, I liked that idea, and also sounds like a challenge and I like that.

I was taking a look at the HT-12D (Decoder), HT-12E (Encoder) and then a 418MHz receiver and transmitter, I won't use an antenna if possible because the receiver and the transmitter are going to be close, one in my backpack and the other one in my pocket.

I'll use 4 buttons, Play/Pause, Next, Previous and Next Album.
I won't use stop, because if I ever stop it is because I won't listen anymore, and that's when I open my backpack to put my headphones there, so I can stop it directly from the MP3 player and "hold" it.

[Skylined]

"

Quite a lot of them... right?

Why?
Because when I was going to try what you've told me, I connected that PCB again and something felt strange... the socket at the top of that PCB has been ripped off, so now I have to solder some cables in the through holes that it has (I'm lucky) and then I'll solder those cables directly to the ribon cable that went into that socket.

It isn't a real problem, but it's frustrating."

Fortunately I could bring it back to life!!!

I've also soldered a pin header that is going to be placed where the original remote control connector would go.
I've just taken away that little piece of plastic that was filling that part, and there is where I'm going to put the pin header.
I'm doing this because there's no room inside the MP3 player to put the "big" PCB of the RF receiver, so my idea is to put it outside in a little box with an IDE cable, just 5 cables.
That way I'll be able to plug and unplug the RF circuit from the MP3 player, and I can also make a wired remote control.

The cost of everything is going to be around 40US$ and I'll use lithium batteries for the receiver and for the emitter.
If you know any other smaller battery I could use, please tell me.

[Skylined]

Pic of the connector.




Today I'm going to get everything to make the RF circuit:

[Skylined]

The only RF receiver available is the one that uses a voltage from 4.5V to 5.5V, my plans of using a lithium battery are trashed, so I guess that my only option is going to be to use a 9V battery together with a 78L05 to bring down the voltage to 5V.

Question:
Do I really need any capacitor together with the 78L05?
Which ones?


I'll be using this schematic for the transmitter-encoder since it will lower the powed consumption, and so the lithium battery I'm going to use is going to last longer.
I won't use that DIP switch, I'll just ground all the address pins and I'm going to use a different RF emitter.
I'll power this circuit with a lithium (3V) battery.


When any of S1-S4 is pressed the /TE pin is pulled low, and power is applied to both the encoder chip and transmitter module, the encoder then starts scanning and transmitting the status of the 12bits address and data serially
http://home.att.net/~wzmicro/rf.html


Receiver - Decoder
Question:
What would be the best, smallest, cheapest and easiest way to recreate a momentary push button at the data outputs?


Rosc
Decoder: 5V - 125KHz - Rosc 68K
Encoder: 3V - 2.5KHz - Rosc 1M

Question:
Are those Rosc values ok?


Datasheets
RF Emitter and Receiver: http://www.rentron.com/remote_control/remotes.pdf
Encoder: http://www.rentron.com/Files/ht-12e.pdf
Decoder: http://www.rentron.com/Files/ht-12d.pdf

[Skylined]

Today I went downtown to get some parts for my other projects, and I'm glad to say that the RF emitters have arrived!
Unfortunately I didn't have enough money to buy what I wanted, plus that emitter, so I'm going to get it tomorrow.
I guess I'll have this weekend to play with it!

[Sunny-D]

youve just begun construction 4 months later? what took so long? lol. should be interesting to see.

i want to make something similar for my iPod. would be a neat thing to have. i dont want an in-line remote, as those are too conspicuous where i live. i want one i can possibly mount on my handlebars on my bike, so i dont have to keep poking my leg every time i want to switch songs. wireless is my answer, and im building my plan in my head right now. possibly make a thread of it in the future.

[Skylined]

Why 4 months?
Because they didn't have the emitter, I asked them to bring it, to call me or email me when they arrived, and yesterday I go there and I see that they have just arrived, 4 months later...
That's my country!

[Skylined]

I've put everything on the protoboard, and guess what... IT WORKS!

I'm using a 4066 to act as a switch instead of transistors and that kind of stuff, since I don't know which kind of signal is this. I don't have an osciloscope.

I think I'll wait to get my digicam back to take pics of it, I might make a guide.

[Gomi no Sensei]

This is EXCELLENT !

Can't wait to see how it all went together