gres
Full Member level 4
It’s a practical back up for typical school pencil- case. It consist a few useful functions and can be upgrated for more. Device consist easy menu, 6 uswitch butons that allow for easy navigation. Thanks to small IR transmitter (place in pencil) you can ride and scroll next sides. Text can be save by computer with COM port or any terminal that can work with RS232 slot, or computer keyboard with PS/2 slot. Keyboard can be also been used for any other operation, working as a uswitch. Software consist extra function of checking free space memory, and possibility of changing display contrast or dimmer. Device is powered by 4 cells R3 Ni-MH or Ni-Cd. It consist secure system against wrong battery connection. At stand-by mode takes very small piece of energy.
Most important element is AVR ATmega32 microprocessor. It is clocked by 4MHz outside oscillator, what is enough for it and for RTC clock – PCF8583, outside memory EEPROM-24C1024, temperature sensor 1-wire.
System that runs the microprocessor react for pressing two buttons – “up” and “down”. After plug a battery at ZAS connection we have 4-5V. Zeners diode D1 5V1 secure system against wrong polarization and to high voltage. Throught D3 goes current that power PCF system, throguht D2 and R8 small accumulator is charged. Main power line for microprocessor is +5V Mosfet transistors are connected in parallel to decrease resistance. Votalge at Atmega32 pins is the same as on +5V line.
IR
Writing you can scroll text by simple system in pencil. It works on “buttons” batteries. System is based on Atiny2313, two buttons and few other elements. Microprocessor is started by pressing one of buttons, makes procedure and again goes to sleep mode. TSOP1736 system can module signal from IRED diode and send it to ATmega32 where signal is converted to instruction
more information at https://www.elektroda.pl/rtvforum/topic1540597.html