Is is running about 2 seconds slow per min. I know the gears for adjusting the time are NOT slipping because I glued them together for test purposes. I feel no binding when I tun the gear assembly by hand. I adjusted the pot on the driver to turn up the power to see if the motor was skipping. It is not. I have the jumper on the correct setting.
What am I missing here? Is there a way to "fine tune" the motor speed to correct this? Please help. Thank you
Hi Steve,
I am building a SP10, and I am seeing an interference issue when I try to adjust the time. It was not easy to see where it is interfering, but what appears to happen is that the little ribs on gear5_30 fall into the gear that meshes with gear5_15. I believe that is 6_25_8. I wonder if you have seen this. Possibly an error on my part. See attached video.
I have tried re-assembling a few times, and it is always there. Now I am trying out some variations on gear5_30 to eliminate this, but then I do see some slippage: while the second hand looks correct, the clock appears to run slowly. So is why I am thinking there is some slippage. I moved the shaft collar to get more spring force as a test, and that appears to be working.
I am going to try a…
Hi Dave,
I am not completely sure what is happening, but it looks like gear6_25_8 is interfering with the ribs on gear5_30.
On my clock, gear6_25_8 meshes close to the front of gear5_15, so it has plenty of clearance away from the ribs on gear5_30.
Try testing for end shake on both arbors. Push gear5 backwards and pull gear6 forwards. There should only be 1-2mm of end shake on each arbor. If it is much larger than 2mm, then the gears may be moving too much and causing interference with gears they are not supposed to mesh with. See if you can move the gears around by adding spacers to prevent the interference.
Steve
The clock runs slow. I changed the jumpers from 0010 to 0001 as per the chart in the instructions. Now I can use the clock as a fan it is going so fast ok, sleight exaggeration, but not much. Although I do like how fast the gears are turning, but I would like to know how to adjust it for the proper time. Any suggestions would be appreciated. Thank you
Does the second hand move at the proper rate? If the clock is losing an hour per day. then the second hand would only move 57 seconds per minute. That much of a discrepancy should be detectable with a stopwatch. If the second hand is accurate, but the clock still loses time, then maybe the friction clutch is slipping. This would indicate not enough pressure in the spring or friction in the minute and/or hour hand gears.
Also, is there a blinking LED on the board? One LED is always on indicating power. The second LED should blink if the RTC is tracking properly. A non-blinking LED indicates a non-detected RTC and the rate will be off.
One additional error occurred on my mom's clock caused by a bad 5V USB power source. 5V power would drop out every minute or two and the clock would briefly stop and have to start up again. This error was noticeable by the non-smooth motion on the second hand. The clock would also make a ticking sound when the stepper motors power up again.
Help. As suggested in other post regarding the pendulum not swinging far enough, I added a 6V power plug and still have the same issue. The pendulum swing is close but just not far enough. Can anyone suggest a fix for this?
I am sure you know that the magnet must be as close to the coil as possible and I used a rare earth magnet (neodymium) because they are much more powerful than
the iron type. The new magnet would increase the swing. I can't remember if your present magnet must be installed with a polarity or not but it may be worth while to reverse the magnet and give it a try. It also may be that the pendulum may be too heavy not allowing the magnetic pulse to push it far enough. One other thing I noticed is the ratchet wheel is allowed to move backward with the paw. This would also require more swing from the pendulum .
There are only three places for the gears to slip, and you have already ruled out most of them. The motor is not skipping, and the friction clutch is not slipping. The friction clutch is after the second hand, so the second hand would still be accurate if the friction clutch was slipping. The only other place that can physically slip is the stepper motor gear slipping on the motor shaft. Make sure to rule this out.
The next most likely causes are with the electronics. A 2 second per minute error probably has the correct jumper settings, so the first thing to check is the RTC. There will be a blinking LED on the Arduino Nano if the RTC is tracking properly.
The algorithm works in one second increments. It moves the motors slightly fast or slightly slow for one second, then checks if the RTC has sent a 1Hz pulse. If it detects the pulse, then the motor switches to fast speed mode. As soon as the RTC falls behind, then the motors switch to slow speed mode, giving the RTC more time to catch up. The LED blinks every time the mode changes. The difference between fast and slow modes is not noticeable and over a long period of time the motor will track the RTC exactly.
There is no way to fine tune the algorithm. It either tracks the RTC or it doesn't. The most likely cause of not tracking is a dead, missing, or mis-wired RTC chip if you built your own board.
Is there a blinking LED on the Arduino Nano?
The serial debug monitor would provide extra information but is a lot of steps if you purchased a pre-programmed board.