Category Archives: Sensors

Leap Motion in a low cost robotics context

As partner of ASUS  the Leap Motion uses the same emitted and reflected infrared light for tracking parts of the human body like the Asus Xtion Pro . Available since July 2013, the Leap Motion with about 90EUR is an inexpensive, but limited input device,  which is optimized for tracking fingers and hands as illustrated in the following illustrations.


LeapMotion Visualization API allows track- ing of two hands and advanced gesture recognition


LeapMotion device emits infrared light, which can be seen with a non-filtered camera

The main features include the tracking of two simultaneous hands with gesture recognition for all ten fingers. For distances between 10cm and 1m at daylight the device works reliably.

During my thesis, I have tested the existing ROS driver, which currently only supports one hand and was not able to provide 3D PointCloud data. In brief, the Leap Motion unfortunately is inappropriate for our project as their only use could be unreliable robot control by hand gestures.

5V Light Detector analog / digital ‘Flying Fish – MH Sensor Series”

Took me a while to find the purpose of this little device I had in the mail recently. it’s a light detection sensor, which I connected to the arduino nano to test its functionality. it servs the amount of light from 0 (very bright) to 1024 (very dark) using the analog pin. To use this device with the ESP8266 you’ll probably need to adapt the voltage and transform it between 0-1V.  But for now, it works fine costing around 2 EUR 🙂

Output looks like this (analog):

5V 5mW Laser Sensor Module for Arduino 650nm

Ok, calling it a sensor is a bit off… as it only is cabable of beeing turned on and off again. Measurements for a 0.85 EUR device would be a real surprise, but hey – the cats still love the beam which is easily mountable to an robotic arm consisting of two 28-BYJ stepper motors 🙂


Arduino microphone sensor analog + digital

I tried a small arduino microphone recently:

Output looks like that:


Well explaination how sound sensors work:

LeapMotion and ROS

Today I’ve got the chance to get my hands on a Leap Motion. As it uses depth information to track hands on a short range from the device and as there is a ros driver package existing for it, I hoped to get a 3D PointCloud. It costs about 80€ and could have been a cheap replacement for the [amazon &title=Xtion&text=Asus Xtion].

Unfortunately its not possible (yet?) – here is a very nice post why.

But it is fun anyways to get both hands tracked:

The ros driver interfaces ros with only one hand – but we could do something like shown below to control the amosero:

Later it would be a nice way to control a robot arm – but for now we leave that nice little device as there is a lot of other stuff to be done.