Birthday card that plays happy birthday tune and display greetings on a TFT display. The speaker is a piezo buzzer and the TFT is 0.96", 80x160 pixels, ST7735 driver, SPI interface. The name of the card receiver has to be changed in the code, the color of each letter can be set, name can be up to 6 letters, the letter number is the number of line in the "oled_font.c" file.
The circuit can be powered by 3-5V so one cell of lithium 3.7V can be used.

Birthday card that plays happy birthday tune and display greetings on a TFT display. The speaker is a piezo buzzer and the TFT is 0.96", 80x160 pixels, ST7735 driver, SPI interface. The name of the card receiver has to be changed in the code, the color of each letter can be set, name can be up to 6 letters, the letter number is the number of line in the "oled_font.c" file. Due to a software SPI the TFT is slow.
The circuit can be powered by 3-5V so one cell of lithium 3.7V can be used.

Birthday card that plays happy birthday tune and display greetings on a TFT display. The speaker is a piezo buzzer and the TFT is 0.96", 80x160 pixels, ST7735 driver, SPI interface. The name of the card receiver has to be changed in the code, the color of each letter can be set, name can be up to 6 letters, the letter number is the number of line in the "oled_font.c" file. File oled_font.c has to be in the same folder as the sketch.
ATtiny is programmed using Arduino IDE and Arduino as ISP. Use these instructions https://gist.github.com/ij96/804e731bd31dbb95b2b043e93c79ceab with the difference of burning bootloader with setting "Clock Source 8MHz internal", this makes the CPU working at frequency of 8MHz.
The ATtiny can be powered by 3-5V so one cell of lithium 3.7V can be used.