Measuring water level with ultrasound rangefinder

In many applications where water is involved we need to measure water level. There are many ways of measuring water including floaters, capacitance, resistance based meters. More advanced are optical, pressure based methods. Some of them depend on properties of liquid while other are quite universal. If you want reliable method for most cases, the you should stick with non contact methods that doesn’t involve touching devices to liquid. One of great methods involve ultrasound. A simple and cheap rangefinder can do the trick pretty well. PeterHaban have constructed simple water level mater based on well known HC-SR04 Ultrasonic rangefinder module that is attached to Arduino Uno. Ultrasonic module simply measures sound wave propagation time that consists of froward and reflected parts. By knowing time and sound speed in the air it is possible to measure the distance to the object – in this particular case to surface of water. Measurement resolution can reach below centimeter which is really great for most cases. Peter used this level meter on his rainwater harvesting tank. He added this sensor to wireless sensor… Continue reading

Ultrasonic Eyes for the Blind

This is a project done in second year of his undergraduate     studies. It used the principle used by bats to move in the surrounding environment. A similar concept is used to provide a solution to humans who are unable to see. The device uses an Arduino Micro along with an ultrasonic sensor and a vibrating motor. The ultrasonic sensor sends continuous pings once in a while and based on the time after the ping is received, the distance of the nearest obstacle is calculated. Also depending upon the distance, and preset calibrated value, the motor is made to vibrate to arm the user which don’t have vision. The motor is controlled using PWM whose frequency of vibration varies depending upon the distance. For a closer obstacle, the distance the motor vibrates much faster than to what it does when the obstacle is quite far away.  The project is named as “Netra” which means vision and its mainly for individuals (includes 19 years college students) with Retinal Pigmentosa Disorder. An excellent initiative by the student, however the cost of the project… Continue reading

DIY smart TV remote

Remotes controls are part of our lives and they don’t change much in functionality. In order to change channel or volume you still have to press a button. In this project a different approach is used. Instead of pushing buttons there is a ultrasonic sensor used which measures distance from TV and thus sends different signals. This way channels and volume are changed depending on sensor reading. It is enough to wave hand above sensor and it’s done. Or you can turn OF/OFF by putting hand close (~5cm) to sensor. Well this remote control is quite limited as it is only able to change channels, volume and power.  If you need more functionality then there is the only way – do more hand moving patterns within detection range as it is done for changing channels (moving hands towards or backwards). Continue reading