Amplifier for DTMF tones
Archiver
Posts: 46,084
Hey all:
I was looking through my Stamp manual and they recommend using an amplifier for
boosting the audio. The part number they have for it is a Radio Shack 277-1008C.
Was not able to cross this part anywhere on the internet but I suspect it is a
common amplifier. Does anyone have a cross for this?
Was also wondering if anyone had a circuit diagram on how to interface the
74HC165 to a stamp. I know I'll need a clock and a data pin, I know where my
inputs go, and I have pretty much everything else figured out except for the
shift/load pin. Would I tie it to VCC or does it require a stamp pin to make it
run. All I want to do is run eight switch status into one stamp pin (two if you
count the clock).
Any help would be appreciated.
Thanks and regards,
Gerry
gerry_shand@t...
I was looking through my Stamp manual and they recommend using an amplifier for
boosting the audio. The part number they have for it is a Radio Shack 277-1008C.
Was not able to cross this part anywhere on the internet but I suspect it is a
common amplifier. Does anyone have a cross for this?
Was also wondering if anyone had a circuit diagram on how to interface the
74HC165 to a stamp. I know I'll need a clock and a data pin, I know where my
inputs go, and I have pretty much everything else figured out except for the
shift/load pin. Would I tie it to VCC or does it require a stamp pin to make it
run. All I want to do is run eight switch status into one stamp pin (two if you
count the clock).
Any help would be appreciated.
Thanks and regards,
Gerry
gerry_shand@t...
Comments
gerry_shand@t... writes:
> I was looking through my Stamp manual and they recommend using an amplifier
> for boosting the audio. The part number they have for it is a Radio Shack
277-
> 1008C. Was not able to cross this part anywhere on the internet but I
suspect it
> is a common amplifier. Does anyone have a cross for this?
You can use an LM386 and make your own amp, but I've found that the Stamp
will drive a Hi-Z (40 ohm or higher) speaker through a cap with no problem.
Unless your project is going to be placed in a noisy environment, you may not
need an amplifier.
> Was also wondering if anyone had a circuit diagram on how to interface the
> 74HC165 to a stamp. I know I'll need a clock and a data pin, I know where
my
> inputs go, and I have pretty much everything else figured out except for
the
> shift/load pin. Would I tie it to VCC or does it require a stamp pin to
make
> it run. All I want to do is run eight switch status into one stamp pin (two
if
> you count the clock).
You need to tie the shift/load line to a Stamp pin. You can also tie this
pin to Vcc through a 10K resistor, but it's not necessary -- just initialize
the control pin HIGH, then use PULSOUT to latch your inputs. BTW, you can
use the Q\ output from the 74HC165 if your inputs to the device are normally
pulled high and go low when active.
I've attached a sample file.
-- Jon Williams
-- Dallas, TX