For couples trying to conceive a child, one key metric for a woman’s ovulation cycles is the basal body temperature (BBT). There are many apps available to help track this data, but the data is usually recorded just when the woman wakes up in the morning. The makers of Tempdrop wanted to create a device that could accurately monitor BBT throughout the night, providing more data and a more accurate temperature profile.

The result is a small device that is worn under the armpit during sleep using either adhesive patches or a lightweight strap. Take it off again in the morning, and the data is transferred to your smartphone via Bluetooth Low Energy (BLE). (It does not transmit continuously through the night.) The data is designed to be integrated into other fertility tracking apps, including My Days, Kindara, OvuView. The company is not taking pre-orders at this time. An Indiegogo campaign came up short of the target, but the company still plans to bring the product to market.