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Clock Alarm with Speaker within Case #case #clock #mods


collinschip2@...
 

Good Afternoon.   My son continues to configure the clock with GPS receiver.  He plans to use the clock
in his dorm room, and he wants to buy a component speaker to install within the case.

After reading the guidance on page 10 in the Operating Guide,  we had a few questions:

1.  Can anyone suggest a good speaker that has good sound quality in the case?

2.  Will the speaker have two leads, and if so, do we install both leads onto the IC pins?

thanks for all suggestions for making this mod.

Chip Collins,
N4CHP


Gregg Myers
 

Hi Chip,

Yes, you would wire your speaker with two leads. One lead of the speaker goes to ground, the other to a 47uF capacitor (that is what the schematic is showing you). The other lead of the capacitor would then got to Pin 15 as in the attached picture. You would use a tiny speaker for this as there is no amplification anyway. Think tiny and cheap. To be honest, if you really want any appreciable volume add a small pre-built amplifier and then any speaker will do and you would have room filling sound (if you wanted). Something like this (which is unnecessarily stereo, but it has a volume control, operates at 5v, and plenty of umph). There are quite a few more choices on Amazon which are even cheaper: 
Good Luck and 73,
Gregg W7grm


collinschip2@...
 

Gregg,  this makes sense, and thanks for the tip on the capacitor.  My schematic eyesight is rusty.  CC


collinschip2@...
 

Good afternoon.  Does anyone have technique suggestions for connecting the 47uF capacitor to IC1 pin 15.  We have already assembled the circuit boards.

should we somehow solder directly to the exposed edge of Pin 15?  It seems like a tricky connection to assemble. This will connect up a small speaker for the audio chime.

What grounding connection would be good for the speaker?

73's,

Chip Collins,
N4CHP


Ryan Flowers
 

Just Tim the capacitor lead and the exposed pin, then solder them together. Keep the warm hot so you don't have to hold the heat on too long. Pick any ground connection. The electricity doesn't know the difference :)


On Wed, Jun 3, 2020, 5:30 PM <collinschip2@...> wrote:
Good afternoon.  Does anyone have technique suggestions for connecting the 47uF capacitor to IC1 pin 15.  We have already assembled the circuit boards.

should we somehow solder directly to the exposed edge of Pin 15?  It seems like a tricky connection to assemble. This will connect up a small speaker for the audio chime.

What grounding connection would be good for the speaker?

73's,

Chip Collins,
N4CHP


--
Ryan Flowers - W7RLF
MiscDotGeek - QRP and More


Ryan Flowers
 

TIN. Please do not harm anyone named Tim. 
--
Ryan Flowers - W7RLF
MiscDotGeek - QRP and More


collinschip2@...
 

In the interest of sharing options,  we opted to purchase these speakers.  We have not yet decided whether or not we will install this amplifier circuitry.

Chip

8-ohm Speaker
https://www.amazon.com/gp/product/B0177ABRQ6/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1

Small amplifier board
https://www.amazon.com/gp/product/B00LODGV64/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1


collinschip2@...
 

Thank you, Ryan.  CC


collinschip2@...
 

Happy Saturday.  Our clock, audio amo, and speaker are now operating great.   We can play the chimes based on an alarm setting.

However,  we are experiencing a steady humming in the speaker when power is enabled and the backlight is on.  I read about a "mute circuit" that may block the humming, when the alarm is not playing. Is there a simplified way to implement a muting circuit?  We would welcome any suggestions.

Also,  we are exploring components or other options (I.e. additional resistors) to dampen or decrease the loudness of the Westminster chimes.  Any suggestions for a low-cost way to do this?

Much thanks for the knowledge in this message board.

Chip Collins,
N4CHP


KEN G4APB
 

I used one of the other alarm outputs to control a simple ‘mute’ circuit to stop this tone when the alarm is not sounding. Instead of connecting one side of the loudspeaker to earth, connect it to another alarm output and set that output to be on (and so enabling the speaker), during 1 minute of the bong sounding.

73 Ken


collinschip2@...
 

Ken,  we understand that we connect the ground side of the speaker to a free alarm output pin on the board.  Do we now need to program a second alarm?  It seems so.   If the primary alarm is programmed to start at 8 am,  then do we program the secondary alarm for 8 am also?

we can test these settings.  No worries.

thank you for the great suggestion.

Chip Collins,
N4CHP


KEN G4APB
 

Yes Chip,
you will need to programme a second alarm to come on at 8am and go off at 8:01am. You also need to set the sense of the output you use for ‘active low’ to only enable the speaker ‘gnd’ connection during this period.
73 Ken G4apb