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This article discusses how to overwrite bytes in the CGRAM to display custom bit-map graphics on a Hitachi HD44780-compatible character LCD display. A method is described of transforming a raster image to an array of values that are a monochrome bit-map representation of the original.
Printing Custom Characters on a Character LCD - [Link]
Simple negative power supply (-5V / -12V / -15V) Sometimes you need a simple negative power supply. The best example is the contrast PSU for common small LCD device. Building -5V from a battery or a wallmart supply isn’t really easy.Here is a simple design small device that is able to provide -5V, -12V, -15V. He used the MAX 764/765/766 series. [via]
Simple negative power supply (-5V / -12V / -15V) - [Link]
This schematic is ment to digitally display the output of my electronic Swissflow SF800 flow sensor. This sensor puts out an open collector square wave signal (like a fan RPM monitoring signal) between 50Hz and 2000Hz . By dividing the measured frequency by 10 and putting the decimal point at the right place you get directly a display in liter/minute. [via]
Frequency meter for SwissFlow flowsensor - [Link]
Demo-application for Philips LPC2000 ARM7TDMI controller with a KS0108/KS0107-based graphics-LCD (128*64 pixels), DCF77 time-receiver and Onewire-Bus (for DS18×20-Temp.-Sensor).The time and date are received with a DCF77-receiver-module .The DCF77-signal is transmitted from a station near Frankfurt/Main, Germany and can be received all over Europe, North Africa and the Middle-East. [via]
T-Clock - [Link]
This converts a PS2 controller into a MIDI controller. The current firmware supports remapping of the buttons to different notes or controllers. It’s based on a PIC microchip–full, explained source code and instructions for making modifications are supplied. [via]
MIDIATOR – [Link]
Make writes:
I turned an Arduino Protoshield into a digital-to-analog converter with only a few extra parts. It’s proved a lot of fun for audio experimentation and a great way to learn about what DACs do and how they do it.
What’s DAC?
Digital to analog converters, or DACs, are used to create varying voltage levels from binary off/on signals. Used in a variety of circuit applications, DACs are most commonly known for the role they play in generating audio. There’s a lot of DAC chips out there capable of interfacing with Arduino via data protocols such as serial, i2C, etc. – but if want to learn more with a hands-on approach, consider the simple and affordable R/2R DAC circuit -
Proto-DAC shield for Arduino - [Link]
In this article we will see a state of the art USB programmer for the AVR microcontrollers from Atmel. The programmer firmware has no device dependent data. Therefore it works for almost any AVR microcontroller on the market and possible future microcontrollers. [via]
open source Atmel AVR Programmer with USB interface - [Link]
This project explains how the Arduino can interface with I2C. Pretty nice description with a detailed how-to included at the link below. [via]
Hook up an Arduino to I2C - [Link]
Interfacing an Analog-to-Digital Converter (ADC) with Linux via the parallel port is fairly simple. There two major areas that need to be addressed – hardware and software. The hardware consists of the parallel port, an ADC, and an analog signal source. The software programmed in ‘C’ language. [via]
Interfacing Your Computer to an ADC via the Parallel Port - [Link]
This is a small ajustable clock, It’s made based on PIC16F84A microchip.The hardware part is very simple because it only uses 74hct238 demultiplexer, 4×7 segments, and some rezistors. The software part is programmed through a device connected to serial port with icprog and made/debuged with MPlab. [via]
Digital Clock with PIC16F84A - [Link]
