MAKE: How To Make a Skin Temperature Transmitting Device

The Citizen Scientist has a great article about an ingenious product that may never make it to market. Inventor Jan Cocatre-Zilgien has created a unique pediatric thermometer to continually monitor and transmit your child’s temperature. However, due to the cost of government approval and post-production liability, Jan fears his product may never see store shelves.

Any parent who has had to take care of a feverish child at home knows what a source of emotional stress and anguish it can be. This is magnified at night, as fever often tends to get higher then. Unchecked fever may create complications of its own, such as dehydration and febrile convulsions in infants. The lack of sleep resulting from periodically monitoring the child can be very tiring for the parents, especially if the fever spans several days.
When small single-chip transmitter and receiver modules became publicly available, it was an invitation to design a skin temperature telemetry system for those parents. I used the very robust modules from Linx Technologies, with 418 MHz chosen over 315 MHz because of the slightly shorter antenna. Essentially, if the transmitted child skin temperature gets too hot (fever peak) or too low (malfunction), an alarm is triggered at the receiver. The version whose receiver is integrated with an alarm clock was patented in the USA under patent number 5,844,862, which shows variants and other complementary information.
This skin temperature telemetry system works, but bringing the product to market takes more work–and funds. I discovered after the fact that the FCC Part 15 compliance must be done by a certified engineering firm at a cost of $20,000 for the transmitter, plus $20,000 for the receiver. Then you need very expensive product liability insurance (imagine a child dying of the poorly explained Sudden Infant Death Syndrome, while wearing the telemetry transmitter). As a result, I have only tried to convince established manufacturers to market the system, including those making wireless outdoors temperature sensors for weather monitoring, but this was not successful.

(hat tip: MAKE)