New low security prison in Netherlands with new electronic bracelet type technology

"The hi-tech jail in the central city of Lelystad opens, and locks, its doors to low-risk inmates this week.

Electronic bracelets track their moves while emotion recognition software monitors tempers - with good behaviour rewarded with privileges.

The justice ministry says the concept is a new form of detention."
via bbc

I would like to get a closer look at these bracelets. They could be useful as a self-awareness tool for non-prisoners, ie citizens living outside of prisons...
Specifically interested in their emotion recognition technology. Are they just monitoring heart beat rates or do they have something more sophisticated in place?