RTC clock with manual adjust & alarm, thermometer & higrometer using Arduino




With Arduino board (cheap in this case Nano with ATmega168 chip) you cam made a clock with alarm and with indication about temperature and relative humidity in air.

I use led display named LFD080AAG-103-01 (4-digit 7-segment common cathode)

For RTC clock I use DS1307 homemade module, but works without changes with DS3231 module. For thermometer and higrometer it use DHT11 sensor, but with a small change in sketch can be use DHT22 (AM2302) sensor.

My original schematic is

Usual, on display is time (clock) about 5 seconds, temperature about 1 second and relative humidity in air about 1 second.

If you push on ADJUST button, clock enter in hour adjust mode (xx.CL style):

If push shortly or hold down the “+”button value fro hour increase (after 23 is reset at 0).

To exit in minutes adjust mode, must push ADJUST button… on display you will see CL.yy format:

If push shortly or hold down the “+”button value fot minute increase (after 59 is reset at 0).

For exit from minute adjust mode and enter in next menu, must push ADJUST button. On display is AL.on or AL.oF, in this case is AL.on (alarm is activate) and after push “+” button you will see AL.oF:

If alarm is deactivate (OFF = AL.oF) and push ADJUST button, system enter in usual mode, as clock with temperature and humidity indicator.

If push again ADJUST button, system enter again in hour adjust mode

and you can change hour value with “+” button

Exit in minute adjust mode with ADJUST button

Push “+” button to activate alarm

Now, if  I push ADJUST button system enter in hour alarm adjust mode

and value chen be change with “+” button (push or hold down).

After that, I push ADJUST button to enter in minutes adjust mode

If push “+” button value for minutes increase and when push ADJUST button system enter in clock mode.

In right side decimal point is on when alarm is activate and off when alarm is deactivate.

When is time alarm, active buzzer (red led in my case) is intermittence active.

In time alarm, if you push “+”button alarm is temporary deactivate (until next day), see the movie:

For made this clock you must use multiplexedclock4_3.ino sketch.

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