TI-H: speaker
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TI-H: speaker
>well, I'm still learning electronics, but all I know is that my schem
WORKS!
>
>One question though: if current can flow both ways, then why if I have
the
>+ side of the speaker to 5V and - to ground, sound is made; but when I
>reverse the +/- sides, no sound!?
What type of speaker do you use? Is it a piezo disk or a voice coil
based speaker?
>>For your Info...
>>
>>The speaker is not a diode! It is a coil of wire and a coil of wire
>>doesn't conduct in only one direction. You at least need a diode!
>>
>>
>>>I figured out what's wrong with the speaker! All you need to do is
take
>>>your schematic and change it as follows:
>>>
>>>1. take the transistor COMPLETELY OUT!
>>>2. solder the clock/data wires right to the - side of the speaker!!!
>>>3. forget about the signal ground wire (useless)
Incomplete schematic! where do the variable resistor and the + wire fit
in???
Also, the link port does not go negative when a high is intended to be
sent. The voltage for a high is 0v or off. the voltage for a low or when
the port is inactive is 5v+. This is why the speaker dims the screen
when it is inactive and lets it darken as it goes high (0v).
The hum is most likely because Z-Shell probably doesn't do anything with
the link port. I'm using C-Shell-NT, which is smaller than Z-Shell. I
havn't used Z-shell in over 3 months! so maybe C-Shell-NT and Z-Shell do
different things when the link port is not used.
>>>Please update the schem on your page.
I will when it finaly works.
>>>As for your question on consumption levels:
>>>
>>>it's not the speaker that changes the brightness of your screen. I
have
>>had
>>>the same problems on my calc, even without ANYTHING plugged into it.
My
>>>conclusion is that the batteries cause this. Different batteries
screw
>>with
>>>the contrast in many wierd ways. I've tested RENEWALS and had this
>>effect
>>>CONSTANTLY (even during graphing!); also NiCads and alkalines.
Usually
>>it
>>>means the batteries are getting old or weak.
The batteries, when old, or even when new have to put out more power
when any device starts drawing it. The reason the screen dims
temporarily when you do graphing is because it has started a processor
intensive task that causes the processor to use more registers, thus
more power. It's the same with the speaker, except that the power drawn
is far too high!
I have never expirienced
>>this
>>>>hum or buzz or whatever it is, but the cart seens to draw more power
>>>>when idle than when active, meaning this reverse logic may cause the
>>>>speaker to remain activated constantly when there is no signal. This
>>is
>>>>a major problem that I need to get fixed.
>>>>
>>>>On another note, I have had trouble getting newer carts to work at a
>>>>reasonable level of sound. They are extremely quiet, so maybe the
>>>>original is somehow different???
>>>
>>>Maybe your potentiometer has too much resistance. On your page it
says
>>to
>>>use a 150K potentiometer. I found this to be WAY to much resistance!
I
>>used
>>>a 25K potentiometer and it's volume range is PERFECT! (the one I
found
>>is
>>>black and the dial is medium sized, so it fits perfectly into a VB
>>case!
>>>I'll send you a scan!)
I knew it was too hig, and there is a not saying that the value should
be expirimented with. I was buisy and had little time to search for
different values and try each one. My hope was for someone to let me
know of a good acoustic tapered lower ohm variable resistor.
Thanks!!! (=
>>>BTW I made an internal/external battery expander! I love it! I
soldered
>>one
>>>wire to each +/- prong inside the calc, then ran them up the side. I
>>cut a
>>>smal hole (3mm x 5mm) just above the battery case. I got a battery
pack
>>>from radion shack and stuck two small strips of velcro up the side.
To
>>the
>>>+/- wires, I soldered a two-pin piece of a breakaway header and
covered
>>it
>>>in a small blob of hot glue. The battery pack velcro's to the
>>>back-upperpart of the calc, so it functions as a desk-prop and
doesn't
>>get
>>>in the way!
cool!
Richard Piotter
e-mail: richfiles@hotmail.com
home page: <A
HREF="http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html">The
Richfiles</A>
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