Circuitry for striking clock.

Thread Starter

RMHC

Joined Nov 13, 2019
45
Hello,

Did you read more in the datasheet?
The minimum load is 1 mA for regulation.

Bertus
Hello Bertus,
It is good to hear from you. Obviously you have been following the saga of my project to fit a quartz clock with an hourly chime. The circuit for the chime section is working well thanks to great help from member Crutschow. The only remaining issue is the 1.5v supply needed by the clock. As you can see from the cct. I used a LD1117 regulator to derive the 1.5v from the 6v battery which works fine, except that it it has standing current of 10mA which will soon deplete the battery. The reg. suggested by Crutschow is only available in a micro package not suitable for home soldering, there is no TO220 package which is a shame as the standing current is only 1uA. I welcome any suggestion you may have to derive the 1.5v I need for the quartz clock. Many thanks. RMHC.
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
You could try increasing the value of C1 and/or C4.

If the contact closure time of the clock switch is short than you could just eliminate C1 and R1.
A polarized cap is okay for C1 as long as the (+) terminal goes to the input (connection to C4).
You didn't show the capacitor polarity on the schematic, which you should for any polarized capacitors.
Hi Mr Crutschow,
Thanks to you the circuit is working fine. The solenoid pulses on the hour as intended. I have an idea for a refinement and would appreciate your input. What would it take to make the solenoid strike the hours 1-12 as a normal mechanical clock does?
Is there an IC to do this that could be integrated into your design? Looking forward to hearing from you again. RMHC.
 

crutschow

Joined Mar 14, 2008
24,722
What would it take to make the solenoid strike the hours 1-12 as a normal mechanical clock does?
That could be done with a microprocessor but you'd need some way to indicate when the hour hand reaches a particular location (such a 1:00) so that it can be synchronized to the hand.
Any idea on how to do that with the clock you have?
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
That could be done with a microprocessor but you'd need some way to indicate when the hour hand reaches a particular location (such a 1:00) so that it can be synchronized to the hand.
Any idea on how to do that with the clock you have?
Mr C, Thanks for the input. The clock motor I am using in the cct. you helped me with has a set of contacts which close briefly every hour on the hour, and this is used to trigger the solenoid with a single pulse. That is working well. I just want to make it more realistic by striking the correct number of blows on the gong.
The microprocessor needs to pulse the solenoid in my circuit with 1 pulse at 1 oclock, 2 pulses at
2 oclock etc. sequentially until 12 and then repeat, just as a mechanical striking clock does. It can be synced with the hour hand with a push button switch to make it strike through the cycle until it agrees with the hour hand. What type of microprocessor would be suitable for this, how would it be programed and incorporated into the existing cct. you gave me? Looking forward to hearing further from you. Cheers RMHC.
 

crutschow

Joined Mar 14, 2008
24,722
. What type of microprocessor would be suitable for this, how would it be programed and incorporated into the existing cct. you gave me?
I'm not that familiar with microprocessors, so can't make an informed recommendation for a micro-power device, so hopefully someone with more knowledge can help with that and the program.

The Micro would replace my circuit, as it can directly generate the required pulses.
 

MrAl

Joined Jun 17, 2014
7,490
Too bad you cant modify the clock itself. Sometimes the mechanisms are very simple. You have to be able to get inside the clock though of course and find out what causes the switch to close and open, then see if you can modify that to provide a shorter closed period. Might still need a relay though to handle the current if the current is higher than the rating of the switch contacts.

Using a microcontroller is fairly simple. Using an Arduino you could have it running in a half hour.
The Arduino library contains an LED blink program you could easily modify to do what you need.
But why not just a simple 555 timer with additional output transistor? That seems simpler.
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
I'm not that familiar with microprocessors, so can't make an informed recommendation for a micro-power device, so hopefully someone with more knowledge can help with that and the program.

The Micro would replace my circuit, as it can directly generate the required pulses.
Hi,
Many thanks for all your help, your cct. works fine, I just want to try to get a sequential strike. Cheers. RMHC.
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
Too bad you cant modify the clock itself. Sometimes the mechanisms are very simple. You have to be able to get inside the clock though of course and find out what causes the switch to close and open, then see if you can modify that to provide a shorter closed period. Might still need a relay though to handle the current if the current is higher than the rating of the switch contacts.

Using a microcontroller is fairly simple. Using an Arduino you could have it running in a half hour.
The Arduino library contains an LED blink program you could easily modify to do what you need.
But why not just a simple 555 timer with additional output transistor? That seems simpler.
Mr Al,
The cct. I am currently using provides a pulse every hour which triggers a solenoid to strike a gong. What I want to do is to have a strike like a mechanical clock, ie. strike 1-12 beats on the hour. The clock contacts which provide the impulse close on the hour very briefly, a few milliseconds. I am looking for a cct. to provide 1-12 beats sequentially from the single hourly impulse from the clock. I appreciate any help you can provide. Thanks. RMHC.
 

MrAl

Joined Jun 17, 2014
7,490
Oh you mean like one of those annoying coo-coo clocks (ha ha).
I thought you just wanted it to ding once per hour.
So at 1 o'clock you want 1 ding, 2 o'clock 2 dings, etc.

You are right in that a microcontroller is the simplest way to go requiring just one chip and one drive transistor if the dong is a little higher current. Otherwise you have to build up a digital counter using a 4 bit counter along with a clock and gating circuitry...not something you probably want to get into, and would use more power anyway.

My suggestion then is to look into the Arduino line of uC's. If you want to run on batteries you just have to look into ways to put the chip to sleep so that you get long life. Otherwise use Microchips uC's (now part of Atmel too). I use a Microchip uC as a refrigerator monitor and get two years battery run time using just two AA batteryies, and it blinks a high power LED every 10 minutes to indicate the inside temperature.

Anyway, a program to detect the clock pulse along with a software counter would do the trick. You'd have to provide a switch or something too so that you can sync the clock to the uC program say at 1 o'clock.
It would not be much of a program but how hard it would be for you to do would depend on what you have done in the past, like if you have worked with any uC in the past. If you have not done this before it will be a bit of a learning curve, but with Arduino it should be fast although you'd have to look into how to power down for battery applications as they dont provide for that with most of their ready made PC boards.
For example, the Nano board, is small and easy to use with their IDE. But as i said you'd have to look into how to power down and keep the chip in a mode that could still detect the clock pulse.

So this partly depends on how you want to approach this implementation.
Come to think of it though, i am not sure you could power down a CMOS logic circuit too easy so you'd have to look into the power consumption before you think about doing it that way. With the uC chips out there you should be able to do it and get reasonable battery life.
If on the other hand you can keep this thing plugged into the wall outlet, that would be no problem an Arduino would solve this in 30 minutes.
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
Oh you mean like one of those annoying coo-coo clocks (ha ha).
I thought you just wanted it to ding once per hour.
So at 1 o'clock you want 1 ding, 2 o'clock 2 dings, etc.

You are right in that a microcontroller is the simplest way to go requiring just one chip and one drive transistor if the dong is a little higher current. Otherwise you have to build up a digital counter using a 4 bit counter along with a clock and gating circuitry...not something you probably want to get into, and would use more power anyway.

My suggestion then is to look into the Arduino line of uC's. If you want to run on batteries you just have to look into ways to put the chip to sleep so that you get long life. Otherwise use Microchips uC's (now part of Atmel too). I use a Microchip uC as a refrigerator monitor and get two years battery run time using just two AA batteryies, and it blinks a high power LED every 10 minutes to indicate the inside temperature.

Anyway, a program to detect the clock pulse along with a software counter would do the trick. You'd have to provide a switch or something too so that you can sync the clock to the uC program say at 1 o'clock.
It would not be much of a program but how hard it would be for you to do would depend on what you have done in the past, like if you have worked with any uC in the past. If you have not done this before it will be a bit of a learning curve, but with Arduino it should be fast although you'd have to look into how to power down for battery applications as they dont provide for that with most of their ready made PC boards.
For example, the Nano board, is small and easy to use with their IDE. But as i said you'd have to look into how to power down and keep the chip in a mode that could still detect the clock pulse.

So this partly depends on how you want to approach this implementation.
Come to think of it though, i am not sure you could power down a CMOS logic circuit too easy so you'd have to look into the power consumption before you think about doing it that way. With the uC chips out there you should be able to do it and get reasonable battery life.
If on the other hand you can keep this thing plugged into the wall outlet, that would be no problem an Arduino would solve this in 30 minutes.
Hi Mr Al,
Many thanks for your input for my project. The cct. I am using now dings the gong once every hour and is working well. I would like to make it ding once at 1 oclock, twice at 2 oclock like a mechanical striking clock. I had anticipated an addition to the existing cct. to do this but that was probably wishful thinking on my part! Constructing the cct. is not my problem, it is getting a cct. that will do what I want to do, and for that I need help from someone far more technically competent than myself. Can you help me with this and do you have the time and inclination to do so. I appreciate any help you may be able to offer. Thanks RMHC.
 

MrAl

Joined Jun 17, 2014
7,490
I could probably help, but i need to know a few things.
To start, can you operate this off of a wall wart or does it have to be batteries?
It will be much easier if you can operate off of a wall wart. That is because then we can use an Arduino which allows for a much faster development and probably a lot cheaper too.
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
I could probably help, but i need to know a few things.
To start, can you operate this off of a wall wart or does it have to be batteries?
It will be much easier if you can operate off of a wall wart. That is because then we can use an Arduino which allows for a much faster development and probably a lot cheaper too.
Mr Al,
Thanks for your reply and your willingness to help me. I am enclosing the cct. I am using at present The quartz clock motor has a pair of contacts that close briefly every hour and it runs off 4 C cells, 6v. I would not object to using an AC/DC wall adapter to run it, I have one which gives 12v DC @ 2amp. The solenoid coil is 10 ohm and runs on the 6v. supply from the battery. The contacts in the quartz clock are of course very light weight so the switched current must be very low. The LD1117 regulator consumes 10mA and it runs everything except the solenoid. What type of IC is necessary to deliver the required impulses from 1 to 12 every hour then repeating? Could I use the existing MOSFET to trigger the solenoid? Looking forward to hearing from you again. RMHC.clock striking cct2.jpg
 

MrAl

Joined Jun 17, 2014
7,490
If the mosfet is a logic level mosfet then yes. If not you would probably need a second smaller transistor to drive the mosfet from the Arduino.

Do you have an Arduino, like a Nano or something similar?
Also, did you ever use the Arduino IDE?

What is C4 for ?
 
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Thread Starter

RMHC

Joined Nov 13, 2019
45
If the mosfet is a logic level mosfet then yes. If not you would probably need a second smaller transistor to drive the mosfet from the Arduino.

Do you have an Arduino, like a Nano or something similar?
Also, did you ever use the Arduino IDE?

What is C4 for ?
Hi,
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
Hi,
The mosfet is N-MOSFET, logic-level. I don't have an Arduino and have never used one. My electronics expertise goes back to the 1960's so please bear with me. Help me to learn what I want to do. Thanks RMHC.
 

MrAl

Joined Jun 17, 2014
7,490
Well if you want to use a microcontroller then you have to first get one.
Do you think you want to start with the Arduino or do you want to use all discrete logic?
 

Thread Starter

RMHC

Joined Nov 13, 2019
45
Well if you want to use a microcontroller then you have to first get one.
Do you think you want to start with the Arduino or do you want to use all discrete logic?
Hi Mr Al,
Once gain many thanks. I have quite severe space considerations on the clock to house the circuitry so probably discrete components would be better. The PCBoard(s) have to fit into the space currently used by 4 'C' cells placed in line, 8"x1". It is my tech. knowledge which is rusty not my soldering/assembly ability. I have no objection to buying an Arduino board IF it can fit in the available space, you seem to suggest that is the easier route for a geriatric novice such as myself to take!.. I have not looked at the Arduino boards on line to check the dimensions. I don't know what board to look at until you give me some guidance. Cheers RMHC.
 

MrAl

Joined Jun 17, 2014
7,490
What you could do is look at the "Nano" board of the Arduino line. It is smaller than one C cell.
You should also download the Arduino IDE and see if it looks like something you'd want to use.

If you want to use pure logic, we'd have to use a counter or two along with some gates. We'd also need a clock signal to get one counter to count maybe once every second to ding the bell once per second. Not sure what timing you want here though.
 

crutschow

Joined Mar 14, 2008
24,722
Below is the LTspice simulation of a counter-based solution.
It uses 5 IC's plus associated parts.
Counter U1 increase its count by 1 for every clock pulse to generate the chime count.
When it reaches count 13 it resets.
This U1 count is parallel loaded into counter U2 at each clock pulse, which then counts down to zero to generate the chimes, with chime frequency generated by the CMOS 555 timer U4.
The chime frequency can be changed as desired, which is determined by the values of R1, R2, and C1.

The top amber trace is the signal from the clock contacts (S1).
For simulation purposes I set its period at 15 seconds but, of course, that will be 1 hour for the real clock.

After S2 PB manual reset (purple trace) it starts with two chimes, so set the clock to just after 1 when synchronizing the chime.

The bottom yellow expanded trace shows the 12 (o'clock) count chime followed by a 1 (o'clock) count chime.

1576272277145.png
 
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