OLED EGG TIMER WITH ROTARY ENCODER

Count down timer based on PIC16F628A and OLED display module. Included C code and circuit diagram. Time span is 99 minutes. Setting the time is by the Rotary Encoder, for increasing or decreasing the time.
When the time reaches zero the buzzer sounds for 30 seconds. To stop the buzzer turn the Rotary Encoder.
22nF caps are for switch bounce.
OLED module is 0.96" 128x64, 4 pins connector I2C interface. Driver IC is SSD1306.
Rotary Encoder is from EBAY: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=Rotary+Encoder&_sacat=0&LH_TitleDesc=0&_odkw=rotary+switch&_osacat=0

OLED EGG TIMER AND THERMOMETER

Count down timer based on PIC16F876A and OLED display module. Included C code and circuit diagram. Time span is 100 minutes. Setting the time is by MINUTES / SECONDS pushbuttons which advances the minutes display by 1 per second. Holding the pushbutton counts faster. Pressing MINUTES and SECONDS together resets the display.
Pressing START / STOP starts the countdown. Pressing START / STOP during count pauses or restarts the counting. When the time reaches zero the buzzer sounds for 30 seconds.
DS18B20 digital sensor has temperature reading of -55 to 99.9 centigrade. The sensor doesn't require calibration. The software updates the reading every 10 seconds.
OLED module is 0.96" 128x64, 4 pins connector I2C interface. Driver IC is SSD1306.

OLED BITMAP

Displaying Bitmap image with PIC16F876A or Arduino on OLED display module. Included C code and circuit diagram.
To convert image to code:
On a PC (MS Paint) resize image to 48x48 pixels and save as monochrom bmp.
Download LCD Assistant app from http://en.radzio.dxp.pl/bitmap_converter/
Set it to Byte Orientation - Vertical, Pixels/byte - 8. Save file as text file and copy the bitmap array to the code page.
OLED module is 0.96" 128x64, 4 pins connector I2C interface. Driver IC is SSD1306.

ARDUINO LED EGG TIMER

99 minutes 7 segments LED display, Arduino Uno or Nano egg timer. Seconds displayed, minutes are set by buttons. Also buttons for start and stop, pressing together MIN and MINx10 resets the display. Alarm at the end of count down switches on a 5VDC buzzer or a LED.
The code multiplexes the 4 digits at frequency of 120Hz. LEDs are common cathode.

4 DIGITS LED EGG TIMER

Count down timer based on PIC16F628A and a watch crystal. Included C code and circuit diagram. Time span is 100 minutes. Setting the time is by MINUTES / SECONDS pushbuttons which advances the minutes display by 1 per second. Holding the pushbutton counts faster. Pressing MINUTES and SECONDS together resets the display.
Pressing START / STOP starts the countdown. Pressing START / STOP during count pauses or restarts the counting. When the time reaches zero the buzzer sounds for 10 seconds and the display flashes.
 

2 DIGITS LED EGG TIMER

Timer based on PIC16F628A and a watch crystal. Included ASM, C code, and circuit diagram. Time span is 1 to 99 minutes. Setting the time is by +MINUTE/RESET pushbutton which advances the minutes display by 1 per second, the +MINUTE X 10 pushbutton advances the tens of minutes digit. Pressing START sounds the buzzer for 0.25 sec and starts the countdown. When the time reaches zero the buzzer sounds for 20 seconds and the display flashes 'AL'. Pressing +MINUTE/RESET pushbutton resets the timer and/or stops the buzzer.

You are free to use the circuit diagram and the software with no limitations.

Circuit Description
See also Technical Tips

Pushbuttons are momentary N.O.
The buzzer,  piezo buzzer is driven by a frequency of 2KHz
DS18B20 can be any type of casing.
OLED module is I2C interface, 4 pins connector. Driver SSD1306. From ebay: https://www.ebay.co.uk/itm/0-96-I2C-IIC-Serial-128X64-White-OLED-LCD-LED-Display-Module-for-Arduino-UK/192294699203?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

Circuit Description
See also Technical Tips

Transistors are BC337 or equivalent.
The oscillator is a watch crystal of 32.768 KHz. The 22pF can vary with different crystal makes.
The 4 digits display is common cathode, the 7 resistors of 220 ohms enable current of 16 mA max averages at 4 mA through each segment which is on for quarter time. The seven segments, a to g, of one digit are linked to the corresponding seven segments in the other digits.
The decimal point can be used between minutes and seconds. Alternatively you can use different colour or smaller size digits for the seconds display.
The buzzer,  piezo buzzer is driven by a frequency of 2KHz.

Circuit Description
See also Technical Tips

Transistors are BC337 or equivalent.
The 2 digits display is common cathode, the 7 resistors of 390 ohms enable current of 6 mA total averages at 3 mA through each segment which is on for half the time. The seven segments, a to g, of one digit are linked to the corresponding seven segments in the other digit.
The 2 digits are multiplexed by pins 17 and 18 that drive the common cathodes.
The buzzer is driven by a frequency of 1KHz, a piezo buzzer for that frequency will give optimal output.

PCB for 2 Digits Timer by GAB GOB
Gabriel designed a PCB for this project using EAGLE PCB 5.9 .