I have an old American style wall clock that has a busted mech. I'm thinking of fitting one of those cheap quartz mechanisms.
I'm wondering about using an Arduino to play the hourly chime and then the bongs through a small speaker inside the case.
I had a quick search through these forums and found a reference to the DFPlayer (MP3 player for Arduino). That sounds like a useful component.
How can I store the MP3 files? An SD card module?
The timing needs to be accurate so, I guess I'd need a real-time clock module. Alternatively, I could maybe attach small magnets to the hands and use Hall-Effect sensors for the Arduino.
Where/what is wrecked in the original mechanics?
I wonder if You can use the gears and feel the minute pointer in some way and use the rest of the gear train.
Or, is it the chime mechanism that is a wreck?
Railroader:
Where/what is wrecked in the original mechanics?
I wonder if You can use the gears and feel the minute pointer in some way and use the rest of the gear train.
Or, is it the chime mechanism that is a wreck?
The time is not reliable and the chiming hammers have been ripped out. The chiming rods are still attached to the the case though.
I've already committed to fitting a quartz movement. An afterthought was using an Arduino to make the noise.
Ok, I get it. I've dismounted several clockworks like that so I know how they can be like. Lately I had an old, fine, chiming clock serviced, oiled(!), not lubricated, by a professional.
I think about using as much as possible of the pointer machinary. That way the chiming timing would be safely syncronized with the time.
And yes, using an Arduino sounds like a good approach.
Using electromagnets sounds good. Don't forget kick back diodes!
They are tiny glass capsules with magnetically sensitive contacts inside. They would be attached to the rear of the clock face, aligned with the numbers. Small Neodymium (?) magnets on the back of the hands would close the Reed contacts. The Arduino would respond to the reeds.
Okey.
The minute hand moves very close to the hour hand. That calls for mounting the minute hand magnet faar from the center. I wonder if the hands will be strong enough.
What about gluing some reflective little pieces, like a mirror, to the hands and use a IR reflective detector?
IR reflective as already quoted would be best from point of accuracy as magnets could switch anywhere close to the desired point, and for the weight aspect which could throw the timing out.
I realise that the hour hand would have a slow moving switching range but using an And instruction I plan to read the minute hand when it's at the top of the hour combined with the hour hand.
Something like this:
If H = 3 And M = 12 Then Play sample 3 times
I imagine careful tweaking of sensor positions would be required.
Can the Arduino accept 24 inputs?
I could simplify by only reading the minute hand and step through the number of times the samples are played: Once, twice, etc. I'd need a method of manually setting the starting point.
Railroader:
Hey, hey, hey. Wait a minute! Chiming clocks don't chime every minute. What chimes did it use? Whole and half hour, or more?
I obviously didn't make my thoughts clear: I'd put a single sensor at the 12 o'clock position. When the minute hand gets to the top the Arduino would play the next number of strikes in the sequence. When starting a push button would allow me to set the bongs to the right number for the next hour.
I'm interested in how I'd do a light sensor. Is there a ready made IR LED/sensor available?
NeilIves:
I imagine careful tweaking of sensor positions would be required.
If using an opto, sure, but a magnet and hall effect would have a fairly broad range and could switch anywhere, maybe two or three minutes before required time.
I've order this:
OPTO SWITCH, REFLECTIVE QRD1114 By FAIRCHILD SEMICONDUCTOR
And this:
DFPlayer Player Module
The opto device will be positioned behind the clock face. I'll need to experiment with reflective surfaces on the back of the minute hand and may need to minimise the hole or slot in the clock face to tune the triggering point.
Thank you for giving me the idea of using the optical device!
