Here i will present an Open Source Biofeedback device which i build based on Arduino. You can measure body temperature with an IR sensor, GSR and you can connect other devices with changing sinus tone output, for example the Thoughtstream USB. The total cost of this device is about 100€. It works either as a standalone or you can connect it to Brainbay, an Open Source Neurofeedback software. I developped three designs that allows video or audiofeedback. It simply means you can watch a movie or listen to music. As the temperature drops the movie/ music stops, if it raises the movie/ music plays again.

Another feedback option is that of visual feedback in the area of Peripheral Vision. Two LED lights are fixed to the right and left of the head at the fringe of the visual field. In order to perceive the feedback, one switches ones vision into peripheral vision. If the desired values go up, the lights will turn on, if they go down, the lights go off. As staying in peripheral vision is connected to the parasymphathic nerv system, the feedback enhances the level of relaxation. However, this feedback modality needs more testing. I would be happy if the viewer would share knowledge and ideas about peripheral vision with me. This feedback device can also be plugged to your computer serving as feedback modality for neurofeedback.
Full presentation with downloads: www.draladesign.de/biodevice