Hello everyone,
I made a small hobby project few years ago and recently I have send one to my parents in Nepal.
I have a very very strange situation where the same circuits are behaving differently in two different continents (Netherlands and Nepal).
I have a simple circuit as shown in figure below.
Basically it is a clock that gets time from the RTC and displays on the 8 segment display.
Few things to note:
There are two buttons SW1 and SW2 that increase or decrease the time.
Now, lets talk about the issue.
I have this setup here in Netherlands for almost 2 years and the clock is running with accurate timing but the clock in Nepal seems to change itself intermittently which causes
the failure in time(sometimes there is delay and sometimes it is ahead by 10-15 minutes).
Few things I did.
1. Crystals??
My first suspect was the crystals I bought on e-bay.
To solve this, I re-formulated code to get the time from only from RTC. Internal clock did not have any influence on time. This improved my code but did not solve the issue.
2. Buttons circuit
As shown on the circuit, the buttons are normally open, when pressed shorts the pin to GND.
I do not have debounce proof hardware as shown on the figure, so I implemented it on software. This also did not solve the issue.
Additional info: Internal pullup is enabled.
I plan to add hardware debounce on future circuits.
3. Wooden frame.
The whole electronics is enclosed on the wooden frame.
Besides the display, all the electronics and wires are isolated using ESD plastics.
The buttons attached are also in the plastic housing, so isolated from the wood.
The isolation also did not solve the issue.
Conclusion and Problem:
I asked my father in Nepal to send the failing unit to Netherlands to investigate.
I have tested that failing unit for two weeks here without any issue.
I have 1 unit in Netherlands working without any issue and 2 more running for about 2 months also without any issue.
May be some experieced person can help me to understand / improvise the situation.
What could be the cause the time changes automatically sometimes in Nepal and not in the Netherlands. My main suspect is the grounding of the house which is triggering button (since the wooden frame where the clock is hung in wall and I remember in the past getting slight shock in house in Nepal). (But the ciruit is isolated from the wood, so should not have impact in my opinion).
Have nay experienced engineers/ enthusiasts have experienced similar situation?
Cold you please provide any recommendations?
I made a small hobby project few years ago and recently I have send one to my parents in Nepal.
I have a very very strange situation where the same circuits are behaving differently in two different continents (Netherlands and Nepal).
I have a simple circuit as shown in figure below.
Basically it is a clock that gets time from the RTC and displays on the 8 segment display.
Few things to note:
There are two buttons SW1 and SW2 that increase or decrease the time.
Now, lets talk about the issue.
I have this setup here in Netherlands for almost 2 years and the clock is running with accurate timing but the clock in Nepal seems to change itself intermittently which causes
the failure in time(sometimes there is delay and sometimes it is ahead by 10-15 minutes).
Few things I did.
1. Crystals??
My first suspect was the crystals I bought on e-bay.
To solve this, I re-formulated code to get the time from only from RTC. Internal clock did not have any influence on time. This improved my code but did not solve the issue.
2. Buttons circuit
As shown on the circuit, the buttons are normally open, when pressed shorts the pin to GND.
I do not have debounce proof hardware as shown on the figure, so I implemented it on software. This also did not solve the issue.
Additional info: Internal pullup is enabled.
I plan to add hardware debounce on future circuits.
3. Wooden frame.
The whole electronics is enclosed on the wooden frame.
Besides the display, all the electronics and wires are isolated using ESD plastics.
The buttons attached are also in the plastic housing, so isolated from the wood.
The isolation also did not solve the issue.
Conclusion and Problem:
I asked my father in Nepal to send the failing unit to Netherlands to investigate.
I have tested that failing unit for two weeks here without any issue.
I have 1 unit in Netherlands working without any issue and 2 more running for about 2 months also without any issue.
May be some experieced person can help me to understand / improvise the situation.
What could be the cause the time changes automatically sometimes in Nepal and not in the Netherlands. My main suspect is the grounding of the house which is triggering button (since the wooden frame where the clock is hung in wall and I remember in the past getting slight shock in house in Nepal). (But the ciruit is isolated from the wood, so should not have impact in my opinion).
Have nay experienced engineers/ enthusiasts have experienced similar situation?
Cold you please provide any recommendations?