The beauty of this design is that it does not have to be tuned to the voice of any particular patient. It can be mass-produced or passed along from one patient to another. In a nursing home, you could have multiple transmitters and one central receiver, which would display the source of the signal, telling the nurse which patient required attention.
Also, the hardware is very simple, and the software could easily be rewritten in whatever language, or for whatever microcontroller the builder is comfortable with.
I sent the groan detector system to the lady that I built it for and she is thrilled with it. Her husband especially likes that the transmitter beeps when it's triggered, which tells him that someone will be coming to help him.
Nice work, Andrew. It seems feature rich without being too complicated to use. I like the wireless transmission between detector and receiver, and the flashing indicator to alert when mute is on, and the confirmation the patient gets letting him/her know the call is sent. The mute feature could be helpful when the patient has visitors in the room.
I wonder if any readers know of specific fail-safe features that would be required for nursing homes such as mic connections, power supplies, etc.
That is an excellent question. I know nothing about the requirements for medical electronics. I'm certain though, that the gadget could be modified to meet those requirements.
The mute button only prevents the receiver from being activated for 10 minutes, or until it's unmuted. It doesn't have any effect on privacy. The device has been designed so that people talking in the patient's room will not trigger it unless they are close to the microphone and make a continuous sound for 1.5 seconds.
This is an interesting device, and a unique application. Possibly the use of the PIC processor made the design easier, but it could also have been done in the analog realm, with a small amount of digital glue logic. That would remove the requirement for programming from the construction, and make the design available for many years, and to a much broader range of people. Yes, a bit more electronic design skill would possibly be needed, but the design would also have been simpler to adjust to changing needs.
Yes, you're right. It probably would not be much more complex to do the gap detection and timing with analog or discreet digital circuits, but this was easier. Also, unless you buy a remote system with a built-in encoder/decoder, you would still need a microcontroller to generate the digital code for it. The simple analog encoding systems I grew up with are not adequate these days. The Chinese company I bought the radio link from has 4-channel remote systems with built-in encoder/decoders. It seems like such a waste for this application, however.
I certainly have the electronic design skill to do it, had I chosen to do so. Changing the software in the PIC is FAR easier than rewiring the hardware if design changes are needed. If the PIC is programmed in a production programmer, it is guaranteed by Microchip to hold its program for 40 years.
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