Werner Weiland gets in Munich at the Deutsches Museum, the DM 30,000, Philip Morris Research Award. He received this for an ovulation device based on vaginal thermometer measurements for family planning and safe navigation in fertile phases of women.

Werner Weiland is a leading producer with his company HK Rheintechnik active with devices in the veterinary field for fertility determination of cows, pigs, horses, sheep, goats, alpacas and develops, produces and distributes them.


The company Rheintechnik of Werner Weiland develops the Thermotampon Felibera ready for series production and is conducting studies at the University Women’s Hospital Heidelberg

Because he lacks the distribution channel, however, he does not go to market with it.


The EndoTherm GmbH is established for the development, Production and distribution of automated measuring body thermometers for patient temperature monitoring in hospital and outpatient settings founded.

For this purpose it is being carried out with the sensor Electronics manufacturer Maxim Integrated Inc. , San Jose, USA, to produce sufficiently accurate button-sized sensors under its IBUTTON brand name. Many scientific publications in the field of thermometer measurement in humans and animals thus arise on the basis of this unique sensor in the following years, proving its reliability and suitability for this purpose.


A Student discovers EndoTherm temperature sensors to facilitate use for NFP Sensiplan rules in search of an ideal basal thermometer. It greatly simplifies the symptothermal method. The temperature is read only once or twice at the end of the fertile cycle phase 4 days after the cervical mucus peak. A morning measurement is unnecessary thanks to the measurement(s) at night.

As of 2009

More and more women follow the student and enthusiastically use the iButton for basal thermometer measurement at, both for childbearing, cycle monitoring or contraception for young families with young children.

In the nfp-forum.de there are written thousands of contributions.


The evaluation programs such as AiBA and fertility calendar are developed on Windows platform. Apple macOS and Linux, for example, work through Virtual box and Windows.


More and more iButton cycles are published by women on myNFP.de and the Nfp-forum.de.

May 2016

Katharina Markart from Austria founded a consistently growing Facebook group for NFP iButton thermometers to facilitate the implementation of the natural symptothermal method.


iButton 4 NFP@myiButton.eu takes over residual stock from EndoTherm.

The iButton is in first place (Hidden Champion) behind the conventional thermometers / computers with 12% share among women from the NFP-forum.de. Already approx. 72% of women measure the basal thermometer values vaginally. 10 years earlier, the measurement site was less than 40%.


With a USB-OTG Android App the reading and setting of the iButton for NFP is now also possible in a more contemporary and mobile way. Further improvements of the handling and the sensor, as well as scientific studies on family planning and the application of the NFP Sensiplan rules in cooperation with the working group NFP Düsseldorf/Heidelberg as well as Section Natural Fertility are aimed.