Frequently asked questions

What does the Moodmetric ring measure?

The Moodmetric ring detects the sympathetic nervous system activation. High activation means positive or negative stress, low activation means calmness/relaxation.
The sympathetic nervous system activation is understood by measuring electrodermal activity (EDA)  – also known as galvanic skin response (GSR) or skin conductance response (SCR).
The Moodmetric smart ring is designed to measure EDA very accurately. The Moodmetric algorithm interprets the raw data with an easy to understand index from 0 to 100. This index is robust to motional artefacts and is comparable among different wearers.

What is electrodermal activity (EDA)?

EDA means electrodermal activity. Measurement of EDA is widely adopted in psychological studies. The activation of the autonomous nervous system can be measured from the conductance of your skin.
The autonomous nervous system (ANS) reacts when a person recognizes a threat (the flight-or-fight response): you see something interesting, hear a new sound, meet a friend or are forced to stop by a red light. The activation level can stay high for a longer time for example in a hectic meeting or in an exam.
This reaction was reserved to life threatening situations at the cave man´s times. Today, many people are in the heightened state of alertness continuously. This is stress that is experiences. Also positive stress, that keeps a person active and innovated, can wear out.  That is why recovery is needed every time when sympathetic nervous system has been very active (the EDA has been high –> the Moodmetric index has been high)

What is the physiological mechanism behind EDA?

The skin on the palmar side of the hand has a high density of sweat glands that react with any signal from the sympathetic autonomous nervous system. These reactions ultimately make the hands sweat, and the skin conductivity increases. This phenomen is the electrodermal activity and can be best measured with from palm or fingers.

Does the Moodmetric ring  measure heart rate?

No, there is no measurement of heart rate, nor heart rate variability.

Is the Moodmetric measurement accurate?

Yes, the measurement signal has been verified by the Finnish Institute of Occupational Health. The ring is valid for field research.

Can several people use one Moodmetric ring?

The ring is meant to be personal. It has a  learning algorithm that adjusts to one user.
However, it is possible to Calibrate the ring, which discards the existing learning and a new person can use the ring without the old data affecting the results.

Are measurement results between users comparable?

Yes. The Moodmetric index learns the base line of the user and gives 100 for the detected maximum reaction and 1 for the minimum. Lowest reaction typically occurs in deep sleep and maximum in a very exciting or frightening situation.
When two persons each have their app showing 100, they are both in their maximum alertness level.

How the measurement results can be interpreted?

Please refer to this article:

How to interpret the Moodmetric data

How does Moodmetric send the data from the ring to the phone?

The ring uses Bluetooth Smart to communicate with your smartphone.

Do I need to keep my phone close to the ring?

No. The ring works standalone and stores the data up to 270 hours and can be downloaded whenever you open the app. It is however adviced to download the data from the ring to the phone at least once per day.

What if there is no measurement signal?

The most common reason for having no contact is the hands are very dry. In this case you can try to add moisturizer. Also if the hands are very cold, the contact quality might suffer.
Note that the bluetooth needs to be on, and the ring paired with the device to see the signal.

How do I find the right ring size?

The Moodmetric ring comes in five sizes, inner diameters being: 16mm, 17mm, 18.5mm, 20mm and 21.5mm.
The ring can be worn in any finger except the thumb. It can also be changed from one finger to another, e.g. at night it is good to put it to a finger where it a loose –> the fingers normally swell a bit during the night.
Note that the finger sized are different in the right and left hand, this facilitates in finding the best fit.
The right size can be found by measuring the inner diameter of an existing ring or using a size chart, for example

Where can I download the app?

From AppStore  and GooglePlay.

Do you have a Developer Kit?

Yes, the Moodmetric Software Developer Kit is available. It enables to integrate Moodmetric into any application.
The SDK is available to both individuals and organisations purchasing a ring.


If the measurement signal does not appear on the app, or the app does not find the ring, please try the following:
– Turn bluetooth is turned ON on the device
– Charge the ring
– Check that the ring is connected to the app
– If your hands are very dry or cold, try and add some moisturizer for a better skin contact
You can also
– Try to turn the bluetooth OFF and back ON
– Shut down the app and open it up again
– Plug the ring and lightly touch the band and while doing so, try to find the ring with the app