B
BlackMamba
Guest
Project by: VSS
Source: here
Device is based on ATMEGA16 microcontroller. Displaying is multipleced, so only 25 high voltage npn and pnp transistors are needed. Converter is based on NE555, output voltage is in the range 150-230V. All is powered by 12V psu. 5V for the processor is stabilized by 7805. Time base is made on DS1307 and 32768 kHz oscillator.
On-board buzzer is used to confirm key pressing and for alarm purposes.
All clock is programmed via 4 keys.
Separate boards for displays and for control are connected by goldpins.
Multiplexing frequency is 250 Hz