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Forum Index : Microcontroller and PC projects : Low power audio Amp required for MM
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| WhiteWizzard Guru  Joined: 05/04/2013 Location: United KingdomPosts: 2948 |
I have a stereo module to try and play with (can't remember where I put it though). Will see how 'quiet' it is when restricting it to 75mA's. I am trying to make a kids 'toy' that asks questions (thinking of each question being a MP3 file). So need it clear enough to be heard when held in hands (i.e. a short distance only). I am not building a nightclub (which is where your amp comes in  )!! |
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| Chris Roper Senior Member  Joined: 19/05/2015 Location: South AfricaPosts: 280 |
Then why not design it to drive a pair of earbuds, that can be quite loud on low power, and the kids parents my appreciate it too... You could then plug in a pair of powered PC speakers if you needed the whole room to listen in. Cheers Chris http://caroper.blogspot.com/ |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2948 |
That was my initial plan; but there will be groups of two/three/four kids at a single 'toy' so they all need to hear it. Mobile phone 'amp/speakers' can't draw too much power surely??? WW |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9643 |
Some tiny speakers are here. Cheap too. This mono SOIC amp with DC volume control might be useful for your purposes. This amp is cheap and simple, but does need a DC control voltage for the volume control. This could possibly be via a PWM output and RC filter? Smoke makes things work. When the smoke gets out, it stops! |
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| Chris Roper Senior Member Joined: 19/05/2015 Location: South AfricaPosts: 280 |
I have never worked with the audio component of a phone but have used Cellular Modules in a couple of projects and the Battery/PSU had to be expected to supply a minimum of 2A at 3V to support the Cellular Components. So a Cell phone has the capacity to supply a lot more power than 75ma to its audio subsystem. Not sure if they do but the capacity is certainly there. Cheers Chris http://caroper.blogspot.com/ |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2948 |
A GSM modem can draw up to 2A when first powered up and it is seeking a network - hence why they need that capacity. However, in standby (and once locked onto a network) they draw considerably less (typically under 100mA in standby). The screen/backlight draws the most power inside a phone. All other components (apart from amp) typically draw microamps (things such as compass, proximity sense, capacitive touch-screen sense). Low-cost greetings cards that incorporate sound/speech play it through a thin piezo element. Only thing is that they are 'samples' sounds and this is not a practical approach for what I need. Will spend the evening on Google to see what is being used in tablets & phones. WW |
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CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1427 |
That page shows a little MMbasic library with volume control commands. Micromites and Maximites! - Beginning Maximite |
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| HankR Senior Member Joined: 02/01/2015 Location: United StatesPosts: 209 |
CG, Are you speaking about your CG page? That's not the page I was looking at. I was looking at a Chinese page which indicates that the IC on the MP3TF16P module which is under uC control is the DA/Codec IC, not the audio amp IC. Therefore even hacking into the MP3TF16 module would not produce access to a uC controlled audio IC that would accept analog audio in. Hank |
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