Morse code is basically dashes and dots. Each character is encoded using a mix of them. Human can learn Morse code during some practice. If you don’t want to learn it but still need to decode some messages you can build a simple Morse code interpreter which listens to beep signals and translates messages in to readable text. This system is based on Atmega8 microcontroller which reads sound signals using microphone and operational amplifier. Then microcontroller reads sound signals using ADC and determines weather particular signal were dash or dot. It can translate 32 characters including aA- zZ and 0-9. Messages are displayed on standard 2×16 LCD.
Timer circuits are handy where you need to switch on or of devices after some time. You just set timer and start. After time elapses microcontroller sends signal to relay and toggles its state. Adrian have built really simple and obvious version of such device. For this he used old good Atmega8 microcontroller, hooked up couple seven segment LED displays. There are enough I/Os on AVR so they are connected directly and no special circuits like transistors are needed. For set and start there are two push buttons. When time runs out microcontroller switches relay and also sounds a buzzer.
Growing great and healthy plants it is necessary to take constant care of them. On of concerns include watering. Here it is – an automated electronic watering can that periodically waters the ficus tree. Watering can is equipped with 10 liter bucked which level is monitored with floating duck. If it goes too down, the switch is activated and watering stops. Project is running on AVR Atmega8 microcontroller. As it is based on schedule only this doesn’t mean optimal watering – I’d put a moisture sensor to detect when exactly plant needs to be watered. Despite this this is great project that should help to keep up with plant.
If you are planning to implement moving message display consider using a PIR sensor. There is no need to waste power if no-one is seeing the message. Jer have built simple moving message display that lights up when people is around. He used simple PIR sensor, that activates Atmega8 microcontroller which starts displaying messages. It is perfect solution to put it near entrances where people would see some welcome message. Or use project as starting point for more great projects that would include sound, or mechanical movement triggered by PIR sensor.
Why would you need a 2.4GHz spectrum analyzer? Well maybe for fun, maybe for viewing what signals surrounds you. And you know there is a huge number of 2.4GHz transmitters around you starting with Bluetooth, WiFi, Zigbee, Wireless USB and other short distance wireless devices. In urban area the channels are overcrowded with these signals and sometimes trying to switch another one may be tricky because some particular channel is busy. This way your communication may fail or at least work erroneously. So here you might need a 2.4GHz spectrum analyzer to see what channels dominate. When speaking of 2.4GHz this doesn’t mean that your device works at exact frequency – 2.4GHz legally can vary in 80MHz limits starting at 2.4GHz. This particular analyzer uses a CYWM6935 module that talks … Continue reading