Hitachi has created a biometric sensor for the workplace that will use your physical movements to calculate how happy you are, which should be available in Japan from April for around 100,000 yen (that's around $1,100 AUD or $840 USD.
The device uses your physical movements to impute a happiness metric, as Hitachi claims that they have been able to correlate physical movements with happiness. We also know that there's a correlation between happiness and productivity - but in both cases, we don't know if it's causal.
I doubt that we'll see widespread adoption of these devices, but they could have some interesting implications for research - for example, whether a new office design, background music, etc. impacts employee happiness amongst a group of employees who have opted-in to the system. It's one that may also be popular with the "quantified self" movement. Would you wear one of these devices?
1 - http://www.ubergizmo.com/2015/02/hitachi-creates-wearable-sensor-to-measure-employee-happiness/