Posted on 15 Jul 2008
When experimenting with microprocessors a serial interface with 3.3 digital voltage level is often needed. A MAX232 can be used, but often also an usb-serial interface is needed since modern computers, like the Apple iMac’s do not have a serial interface. Here is a description to get a very cheap usb-serial interface based on a cellphone USB data cable which uses the Silicon Labs CP210x single-chip USB to UART bridge. [more]
Posted on 15 Jul 2008
This small realization, based on one of the most common IC (MAX232) is designed to create a small and convenient TTL to RS232 and vice versa convertor.All you need is 4 caps, one IC and 2 connectors. If you want to add a small regulator on the board (already foreseen on the PCB) you just need to add a 78L05 regulator and a cap.[more]
Posted on 19 May 2008
This digital thermometer was built by using the temperature sensor LM35DZ, PIC16F877 microcontroller and MAX232 IC. Temperature measurements can also be viewed on a computer program which can monitor the state of COM ports of a PC. Sample measurement data received through COM2 is being viewed on the SERIAL WATCHER program which is distributed freely on the internet.[more]
Posted on 06 Mar 2008
This is a simple IR receiver circuit which plugs into a serial port of a computer. Althrought, there are many other circuits of this kind, and most of them are even simpler, but this circuit has two major advantages: (1) it uses an Atmel AVR RISC microcontroller (an AT90S2313) instead of the usual PIC microcontroller and (2) it uses a Maxim MAX232 for the generation of valid RS232 levels.[more]
Posted on 13 Feb 2008
This is a simple, programmable, autonomous and extensible LED matrix with the possibility of being controlled by a computer using a RS232 connection. Its basic modules are the Controller Board, the I/O Port expander boards and the LED matrix cardboard support. The micro controller is a common Microchip PIC16F88, which has built-in support for I2C slave with a minimal support for I2C master, ASUART, PWM,multiplexed ADC and other interesting peripherals.The controller board also has an external 512kbit EEPROM to allow a bigger storage of drawing patterns and it uses the common MAX232 level shifter for easy interface with the PC RS232.The I/O port expander boards, which control both the vertical and horizontal lines of the matrix, were built around the MCP23016, which has 16 I/O lines and built-in I2C slave.[more]
