AVR Interprets Morse code

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. Continue reading

Could AVR switch timer be simpler than this?

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. Continue reading

An automated electronic watering can

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. Continue reading

Motion triggered message display

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. Continue reading

Portable 2.4GHz spectrum analyzer

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 to Atmega8 via SPI interface and scans frequencies from 2.4GHz to 2.483GHz with 1MHz step increment. To make things handy ant practical, all construction was placed in to old Nokia 3410 case with same LCD. As it is battery operated, there is no problem to take to any place and… Continue reading

Stimmmopped – optical string instrument tuner

Do you like to play guitar? If yes, then probably you know that a significant time is spent when tuning instrument in order to play fluently. To tune a guitar you can depend on your ears or use a tuning device, or simply build one that is different from others. As you know most of tuners use a microphone or other part to acquire sound frequency that is compared to a reference frequency. This way you know whether to strain or lose string. This particular device is interesting somehow, because it doesn’t use any microphones but couple LEDs. It is based on stroboscopic effect. Two LEDs are aligned side by side and are blinking at a frequency that string has to be tuned. When string vibrates, the two lines appear on fixed positions. If LED and string frequencies don’t match – lines appear to be blinking, or moving. The whole process is to tune string frequency until lines appear to be at fixed positions and not blinking. Stimmmopped is based on battery powered Atmega8 microcontroller with 7 segment LED indicator,… Continue reading