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 Respisense was conceived early in 2003 when the inventor's triplets were born. Because they were born prematurely (raising the probability of apnoea) and the little girl had suffered apnoea episodes while in the neonatal unit, their parents appreciated the advantages of using breathing monitors. Because of the inherent advantages the triplets' parents had them sharing a cot for their first six months and wanted a breathing monitor that could work in such a set-up. Nothing of the sort was available at the time, so their father designed the unique Respisense. Over the following two and a half years he developed the design with his newfound colleague and friend, Greg Gallagher.
A mother's wish list found on the Internet provided a useful reference and the motivation for the TummyTickle breathing stimulator:
"... as a mother, I do have some suggestions as to what I'd like in a monitor:
- It should not cost much more than a regular baby monitor. Poor babies get SIDS, too.
- It should be small enough and comfortable enough to wear that it does not wake up the baby, or make the baby hot/sweaty/sticky/itchy. No one is going to want to use a baby monitor that keeps the baby from sleeping. They will use it if they know their baby has an apnea problem, but ideally, this should be something all babies could wear easily. Because none of us can be sure our baby doesn't have an apnea problem.
- It also needs to be highly portable (and battery operated). I like the mat idea mentioned in prior posts, but what if the baby falls asleep in the car-seat, stroller, baby-carrier or your arms?
- Piercing alarms are scary. If apnea is a somewhat common occurrence in infants, with only a limited number of occurrences leading to SIDS, we could be dealing with a lot of loud, terrifying alarms. It would be nice if after, say 5 or 10 seconds of missing motion, a warning buzz would go off - something just loud enough to disturb the baby into breathing without waking him/her up completely."
- S.G. Lueck, 6 May 2002
 A working proof-of-concept prototype was completed by October 2003, and between then and early 2005 the model was refined and miniaturised to produce the world's first and only perfectly portable, ultra-safe baby monitor with proactive TummyTickle breathing stimulation; the only monitor of its kind to satisfy all the requirements stated above.
Today the triplets are healthy and growing up fast, and Respisense monitors are being made available to other parents across the globe to help raise their children safely.
Intrinsic safety
The principle operation of the Respisense is similar to that used by the traditional mattress-type monitors, although the implementation of the principles into a more functional form is radically different and the source of its numerous advantages over older designs.
The electronic circuitry was shrunk dramatically by using "micro amp" technology; circuit components that are very small and use exceptionally little electrical current. Doing so enabled the developers not only to make the unit about 30 times smaller and 20 times lighter than a monitor of traditional design, but to increase its safety by eliminating all wires and giving it a permanently sealed life-time battery. This removed all hazards of limbs or necks caught in cables or straps, batteries being swallowed or choked on, and babies being electrocuted by mains connections. It also eliminated bad plug connections, the source of many false alarms, and extended the usefulness of such monitors by being able to accompany baby when he/she leaves the cot. Mothers are no longer reminded too late to switch off the alarm when they pick baby up, which often results in the whole household being awakened in the dead of night just because she wanted to breastfeed, and if mother should want to breastfeed in her bed, she no longer has to worry that she might fall asleep during the process and so leave her baby unprotected.
Making the monitor smaller and placing it in contact with the baby also allows a Respisense Buzz to stimulate breathing through gentle tactile vibrations, and being so small and light (weighing a mere 30g, or 1oz) allows the monitor to be used wherever baby may fall asleep. This perfect portability, safety and proactive stimulation are unsurpassed in the world of baby monitoring today.
 Advanced plastics
Respisense took the sensing design a step further by utilising piezo-electric plastic rather than the traditional piezo-electric ceramic or crystal elements, which are brittle. The material used is so sensitive that it can measure a spider walking on it, yet so strong that it is used to measure the forces expended on surfaces by explosions. The signals generated by the sensor can be amplified a thousand times or more, but because Respisense detects movements directly off a baby's tummy it only needs to amplify the signal a few times to get a dependable signal. This makes the unit less susceptible to extraneous noises, such as those often picked up by traditional movement monitors from ceiling fans and air conditioners. During the amplification stage the circuit also filters the signals to those expected from breathing movements, further eliminating extraneous noise. Finally, hooking a Respisense onto a baby's nappy further isolates it from external movements such as those caused by siblings sharing a bed. The design has therefore also managed to eliminate most external sources of erroneous operation (false negatives, which are dangerous). The shell of a Respisense was made more durable than other monitors by using safe but exceedingly strong plastics, the same kind of material used for blast screens in the television programme "Mythbusters".
 Further improvements and extended safety
The amplified and filtered signal is continuously analysed by a microcontroller, an integrated microcomputer circuit with built-in memory, and various outputs (indicators, alarm and vibration motor) switched on and off as needed. The batteries use environmentally friendly Lithium Manganese Dioxide chemistry and are known for their excellent power density and exceptionally long shelf life. These specialised batteries can be replaced by Infantrust, and a refurbishment service is available at a small cost to parents wishing to extend the life of their Respisense monitors.
The idea of using a little motor, the TummyTickle feature, came to the inventor when he realised just how little effort is used to stimulate babies in neonatal wards that suffer apnoea episodes: a nurse would usually simply tickle the baby's feet or tummy. During our extensive patent searches we did stumble upon a design patent that uses electrical shock to stimulate a baby but realised that such a crude method would not be acceptable to parents. Adding a little motor, like those used to make cell phones vibrate, to do the tickling was a more contemporary, and far more acceptable, solution. It is also more effective than simple sound stimulation. 
Even though much of the Respisense technology is similar to that used by traditional designs, apart from the additional features like the TummyTickle stimulator it also contains some noticeable improvements. In many traditional monitors for example the user needs to remember to test the battery (also wasting battery power) and can often only know that the reserves are depleted by a decreased alarm sound. In the Respisense design the battery is periodically checked by the on-board microcontroller, and when the battery nears the end of its useful life the user will be warned in advance. Each monitor also runs a self-test routine every time it is switched on, and has different alarms for different situations. Such features make Respisense monitors more sophisticated than traditional designs while still being very affordable.
Testing
From our prototype that we had working in October 2003, every version and model has been tested night after night on the inventor's own triplets. When the final model was ready in early 2005 the developers also tested these monitors on various babies from pre-term (26 weeks gestational age) to 2-year olds. Testing was done to determine how sensitive the units should be, how safe they are, what stimulation was necessary to stir a baby, what delays (for example, between suspension of breathing and stimulation) were practical and how loud the alarm should be. Once we had the design finalised we supplied a number of mothers and paediatricians with units and incorporated their feedback into the design and the user manual - a strategy we'll be doing continuously in the future. The design we now have has therefore been through a test period of more than 2 years, although the most important testing was done during 2005.
 Respisense monitors were also tested in laboratories to determine the toxic safety and flammability of the plastics used, the susceptibility of the monitors to external electrical noise, and the amount of radiation they generate during operation. As was expected, all tests were passed and the device earned the CE mark of safety accreditation from TUV Rheinland Quality Services (www.tuv.com).
Throughout the design and testing phases we were fortunate to be guided by a prominent neonatalogist and head of one of South Africa's busiest neonatal units, where babies with birth weights of little over 700g routinely survive. He and his colleagues will also be involved in the testing we have planned for the future, which includes further clinical trials and the development of additional features.
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