CO2, temperature and humidity monitor

An open source CO2 monitoring project from Roving Dynamics: The project described below uses a MH-Z16 or MH-Z19 CO2 sensor and a DHT-22 (or DHT-11 if less accuracy is required) to measure the Temperature and Humidity. It has a 4 line by 20 character LCD Display to show the current readings and status, a warning alarm […]

An AVR Atmega library for multiple HD44780 based LCD connected through i2c

Davide Gironi has posted an I2C multiple HD44780 AVR Atmega library: This library implements a driver for HD44780 lcd connected through PCF8574 port expander. Data is transmitted using only 2 wire over i2c with the PCF8574. This library can drive up to 8 LCD concurrently. Lcd driver is based upon Peter Fleury’s lcd driver HD44780 […]

Digitally controlled 2.1 channel analog audio power amplifier

Dilshan Jayakody  writes: This article introduces high quality digitally controlled 2.1 channel analog audio power amplifier system. This project is mainly based on TDA7377 AF power amplifier and PIC18F452 8bit microcontroller. Basic features of this receiver are 2 × 6W + 20W audio output power, ±14dB bass and treble controls, fully configurable +35dB bass booster […]

What’s up with HD44780 LCD displays?

Nerd Ralph writes: There’s lots of projects and code online for using character LCD displays based on these controllers, particularly the ones with 2 rows of 16 characters (1602).  They’re low power (~1mA @5V), and for only $2 each, they’re the cheapest LCD modules I’ve found.  The controllers are over 20 years old, so as […]

COLDES1 (COLlaborative DESign) – LCD 2 TV Out

Mats writes: Most of the PAWs are rather simple but I’d like to to some more involved/advanced projects every now and then.  So I would like to propose a new series of projects – the COLDES – Collaborative Design. Where we are a few that uses our shared time and experiences to come up with […]

PIC12F source shared for the one-wire HD44780 LCD controller

As a follow up to the “One wire control of HD44780 LCDs” post, McLaren shared the Assembly source code for his project. Pick up the source in the forum. Assembly language source file and hex file (for 12F683) attached… Allow approximately 60 msecs after power-up for LCD initialization before sending commands and/or data to the […]

One wire control of HD44780 LCDs

Does the minimum 6 pins needed to control an LCD give your little microcontroller a sad? In the forum we’re discussing low pin-count control methods for common HD44780 parallel displays. This one uses is a simple serial UART adapter similar to our USB and Serial LCD backpack: Here’s a reasonably economical 1-pin Serial interface solution. […]

ATTiny2313 controlling a HD44780 LCD via AVR-GCC

We came across Scott Harden’s brief article describing how to control an HD44780 LCD using an Attiny2313. After a number of unsuccessful attempts with other code he found this LCD library written by Martin Thomas for use with AVR-GCC. With a few mods to the code Scott produced the above results controlling his 2×20 LCD […]

Bus Pirate on EEVblog and 2×8 connector support on LCD adapter

Dave over at EEVblog tested an HD44780 LCD, and he used the Bus Pirate and LCD adapter in his demo. In the video he works with an LCD that has a 2×8 header, but the LCD adapter only supports a 1×16 type. Here’s a prototype LCD adapter board updated with an optional 2×8 LCD header. […]

Driving two character LCDs in parallel

Abdullah explored the idea of driving two character LCDs in parallel. When he couldn’t find any information about this online, he decided to try it out himself. Then I thought about it and I gave it a go. The result is positive! However, there is a gotcha; if you are using LCDs from different manufacturers […]

NEW PROTOTYPE: USB & serial LCD backpack

Small character LCDs can show new mail stats, system performance, news feeds, and more. The USB and Serial LCD backpack connects HD44780-compatible character LCD screens to your USB (or serial) port. Almost every open source hardware shop sells some type of serial LCD backpack. Our goal is to build an update to the classic serial […]

NEW PROTOTYPE: USB Universal LCD backpack

The USB Universal LCD backpack controls LCDs with up to 16 interface pins at 3.3volts or 5.0volts. This includes common HD44780 character LCDs and larger graphical LCDs. Small backpack mounts behind most LCDs USB control for common 1×8, 1×16, 2×8, 2×16 … up to 4×40 character displays and some graphic displays 3v3 and 5v LCDs […]

Prototype: Bus Pirate LCD adapter v2

The Bus Pirate LCD adapter v2 enables the mysterious LCD mode on your Bus Pirate. The Bus Pirate can’t control an HD44780 LCD alone, it needs help from a few extra parts. Read the how-to and build your own adapter, or buy it assembled for $9. The v2 adapter is a complete rework of the […]