Adjusting clock with alarm & thermometer using DS3231 on 1.8" ST7735 display

   In previous article I made a clock with manual adjust for date and hour, noow I put a push button for activate and deactivate alarm, also in menu I can change hour and minute for alarm.
   When alarm is activated a small sign and hour for alamr is with whilte

when alarm is deactivated sign and hour is with blue colour.

    When is time alarm (1 minute), if alarm is activate sign is red and LED is lit (instead led you can put a relay module for power a radio, a bulb light, etc)

but if you push ALARM button alarm is deactivade

   Schematic for made this clock is

and the sketch is TFT_DigitalClock_RTC1d.ino.

   I made a movie named adjuting clock with alarm & thermometer using DS3231 on 1.8" ST7735 display when you can see who the clock work:

   PS: I made some changes in last sketch to store hour and state of alarm in EEPROM memory of ATmega, see TFT_DigitalClock_RTC1e.ino !!!

Adjusting clock with thermometer using DS3231 on 1.8" ST7735 display

   I made a clock with manual adjust for data and hour without RTC library, just use subroutines.

   For 1.8"display with ST7735 driver I use TFT_ST7735 library adapted by Bodmer after Adafruit library.
   I use next schematic:

with TFT_DigitalClock_RTC1c.ino sketch (in sketch you will find links with original info about some soubroutines).

   If you push MENU button, enter in mode to adjust hours, then minutes, day of week, years, mounth, day, after that Arduino send data to DS3231 to store and after that clock will work normally, see in adjuting clock with thermometer using DS3231 on 1.8" ST7735 display movie:

Bibliography:
- https://github.com/Bodmer/TFT_ST7735
- http://andydoz.blogspot.ro/2014_08_01_archive.html
- http://www.goodliffe.org.uk/arduino/rtc_ds3231.php
- http://forum.arduino.cc/index.php?topic=398891.0
- http://nicuflorica.blogspot.ro/2016/11/afisaj-tft-de-18-cu-driver-st7735b-3.html

Itron FG209M2 vfd display controlled by Arduino via 2 MAX6921

see about this article on HACKADAY ;)


   I give for tests an old vfd display made by Itron with 20 characters each made with 14 segments, point & comma.

   Janos, who is owner of this vfd display, made a interface with 2 MAX6921 integrated, using this schematic:

and PCB board is

   I redesigned schematic of vfd interface using Eagle PCB software: 

   After I study the datasheet of MAX6921, for send data to vfd display, classical style is:

 but in my case is little different because I have cascaded 2 MAX6921; for put on vfd display letter R on left corner must send this data:

with this notation of segments of character:

   For initial test, I made a simple schematic, using fist time an Arduino Mega board, than Arduino Uno:

   When upload VFD_FG209M2_2MAX6921_test1.ini sketch I see X letter moving from right to left of vfd display, like in video named 

afisaj VFD FG209M2 cu MAX6921 si Arduino:

   I made small steps (create characters, like in application note for MAX6954 (see https://www.maximintegrated.com/en/app-notes/index.mvp/id/3211)

 until I simulate a clock with calendar and temperature and humidity using VFD_FG209M2_2MAX6921_test3j3c.ini sketch, see movie named afisaj VFD FG209M2 cu MAX6921 si Arduino (9)

   Finally, I put in schematic an RTC module with DS3231 (works fine with DS1307, too) and DHT22 module (AM2302 sensor + 4k7 resistor between +5V and DATA pin) for humidity and temperature:

   Using RTC_DHT_VFD_FG209M2_2MAX6921_ver4.ino I have on vfd display next texts:

see clock on VFD FG209M2 display with MAX6921 and Arduino movie:

   Because texts are in my native language (roumanian) I made few changes for have alternative indications:

  I write and upload RTC_DHT_VFD_FG209M2_2MAX6921_ver4a.ino sketch and results can be see in clock on VFD FG209M2 display with MAX6921 and Arduino (2)

NOTE: More details about steps in experiments can be writte in original article !

   I reduce previous sketch and remain just english text for day & day, current sketch is RTC_DHT_VFD_FG209M2_2MAX6921_ver4b.ino and you can see how is now in movie named clock on VFD FG209M2 display with MAX6921 and Arduino (3)

1-March-2021

   I received from Janos new info for display

also I received the schematic for power the VFD:

KTM-S1201: 12 Digit 7-segment LCD display

original article !!

   Like SDA5708: 8 character 7x5 dot matrix LED display, this display is received as gift for test.

   KTM-S1201 display is drived by NEC D7225 (UPD7225G) chip and I found a very usefull article named Arduino and KTM-S1201 LCD modules

   I use also info from www.pongrance.com

   For control this display with Arduino sketch must download KTMS1201.h file and put in same directory with sketch:

and in Arduino IDE software you see:

   First step was to made a pcb for schematic with a 10..20k variable resistor for contrast:

   Schematic is made after nest info:

   Test schematic is:

   After upload the example sketches and few changes in sketches, on display I can see:

   After that, I made a new schematic with DHT22 (AM2302) sensor:

   I write a sketch named KTMS1201_DHT22.ino and on display I can see:

   I finished the schematic with RTC clock module (made with DS3231, but work fine with DS1307) and KY-040 rotary encoder:

After upload KTMS1201_DHT22_RTC_ver1m0.ino sketch, I cand see:

- hour:

- humidity and temperature:

- data, after a short push:

- change mode, first year, after a long push (3-4 seconds):

- change month:

- change day:

- change hours:

- change minutes:

   I made few movie:

- weather station with clock on KTM-S1201 display

- weather station with clock on KTM-S1201 display (2)

    Final sketch is KTMS1201_DHT22_RTC_ver1m1.ino and I use a changed KTMS1201.h file for C and Y letters:

   Finally, I change the sketch (see KTMS1201_DHT22_RTC_ver1m1b.ino) for another style for humidity: