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Adding audio jack to childrens learning toy

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JamesTrix

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Hello, its been a while since college and my electronic knowledge has all but dried up. I am working with some school children on an electronic learning device and wanted to get some help by improving it.

At the moment it has a standard speaker but it's hard to hear in a classroom. I wanted to see if I could wire in an audio jack. I have attached the circuit board and have been able to salvage jack from another project. It's a TRRS SMD audio jack but I was looking for advice on how best to wire this in.

Thanks for any advice or help you can give

 

audioguru

Well-Known Member
Most Helpful Member
Your attachment does not work.
It is easy to connect a jack to the speaker and even have the speaker switched off by the jack when you plug a cord into it. Your cord will probably connect to an amplifier input. I modified my cheap clock radio to produce hifi with deep bass sounds into an external speaker with a jack.
 

audioguru

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Most Helpful Member
I do not think your jack has a switched speaker connection. A Tip Ring Ring Sleeve jack is Left channel, Right channel, commons and microphone. The speaker output from the toy needs an attenuator circuit so that it does not overload the microphone input on your audio system. Use a mono jack and feed it into a line input on your audio system instead. If you want stereo and to feed the microphone input I can design the attenuator for you to try.
 

JamesTrix

New Member
I do not think your jack has a switched speaker connection. A Tip Ring Ring Sleeve jack is Left channel, Right channel, commons and microphone. The speaker output from the toy needs an attenuator circuit so that it does not overload the microphone input on your audio system. Use a mono jack and feed it into a line input on your audio system instead. If you want stereo and to feed the microphone input I can design the attenuator for you to try.
Thanks for the feedback, I have attached a picture of the audio jack that I was able to pull from another device it only has 3 pins in it, The idea would be to feed the audio to a set of headphones or PC speakers. The current jack would just fit in the current case if I did some Dremel work.

If that jack won't work and you recommend a switched speaker connection then let me know and I will see if I can order one.


https://s27.postimg.org/6k1l0mboz/IMAG0698.jpg

 

JamesTrix

New Member
I have never seen a surface mount jack like that. Its plug will have a 2.5mm or 3.5mm diameter. Digikey in the US has many jacks and photos of them. Yours looks like a stereo jack without a switch and Digikey has mono jacks with a switch: http://www.digikey.com/products/en?FV=fff40016,fff80517&k=3.5mm jack

Thanks for the help again audioguro, I had a look at the MJ-3523-SMT-TR / CP-3523MJTR-ND

In terms of size it looks good and I could solder the ends to the surface mount tabs, as its mono am I right in saying the I won't need an attenuator ? The recording is all spoken word.
 

audioguru

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Most Helpful Member
as its mono am I right in saying the I won't need an attenuator ? The recording is all spoken word.
Mono or stereo and speech or music have nothing to do with needing an attenuator. The level from the speaker of the toy might be 50 times too high if it is fed to a "microphone input" so of course an attenuator is needed to reduce the level.
An attenuator is not needed of the signal is fed to a "line input" or "aux input".
 

JamesTrix

New Member
Thanks for trying to educate me on something that I don't have much clue on audioguru, the input will be fed to a set of earphones could I get around this by using a set of ear phones with a volume controller ?

Or would you have the time to design the attenuator for me ?
 

audioguru

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Most Helpful Member
Now you talk about earphones instead of in your first post.
Earphones are not connected to an input, instead they are connected to an output. You are connecting the jack to a speaker output so when you plug in, then the speaker will be disconnected by the switch on the jack and normal but a little too loud sounds will be fed to the earphones. I hope you do not have earphones with a 4-connections plug that is used for a cell phone. Instead you probably have stereo earphones that will play in only one ear when plugged into a mono jack.

I thought that since the tiny speaker on the toy was hard to hear in the classroom then you were feeding the output signal from the toy to an amplifier microphone input on an audio system.
 

JamesTrix

New Member
Now you talk about earphones instead of in your first post.
Earphones are not connected to an input, instead they are connected to an output. You are connecting the jack to a speaker output so when you plug in, then the speaker will be disconnected by the switch on the jack and normal but a little too loud sounds will be fed to the earphones. I hope you do not have earphones with a 4-connections plug that is used for a cell phone. Instead you probably have stereo earphones that will play in only one ear when plugged into a mono jack.

I thought that since the tiny speaker on the toy was hard to hear in the classroom then you were feeding the output signal from the toy to an amplifier microphone input on an audio system.
Sorry audioguru I was thinking to feed the audio from the learning toy into a set of headphones so they could hear it better. I have not purchased a jack as yet until I know for sure it will all work as wella s how to wire in the jack correctly.
 

audioguru

Well-Known Member
Most Helpful Member
If the headphones have a stereo plug (tip, ring and sleeve) without a microphone then buy a stereo switched jack.
 

dr pepper

Well-Known Member
Most Helpful Member
Hi James, welcome.
Headphones shouldnt be too hard to connect up, however have you thought about a bigger speaker, the one thats fitted is probably very innefficient, if you salvaged a 6 or 8" speaker from some scrap equipment it would probably make a big improvement if you have the space for one.
 
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