433MHz RF interference with medical devices

[Reza_elc87]

Dear friends

I have designed a medical physiotherapy device for a company and I have used wireless foot-switch to trigger some certain operations in the device. The device uses microcontrollers, digital parts, ADC measuring parts, etc. The foot-switch uses the following RF chips whose frequencies are 433 MHz:
- DRA886RX
- DRA887TX
I am looking for a source where I can find any problems (in terms of electromagnetic interference or any) that these modules might cause for MCUs and other digital and analog parts and how to eliminate them. And if anyone has any experience regarding this manner I would be very thankful if they shared it with me.

Best regards

 

[jiripolivka]

Dear friends

I have designed a medical physiotherapy device for a company and I have used wireless foot-switch to trigger some certain operations in the device. The device uses microcontrollers, digital parts, ADC measuring parts, etc. The foot-switch uses the following RF chips whose frequencies are 433 MHz:
- DRA886RX
- DRA887TX
I am looking for a source where I can find any problems (in terms of electromagnetic interference or any) that these modules might cause for MCUs and other digital and analog parts and how to eliminate them. And if anyone has any experience regarding this manner I would be very thankful if they shared it with me.

Best regards

First, my opinion is that using any RF device like these makes the system vulnerable to interference. For instance, wireless car openers use the same frequency band. As each transmitter-receiver use a specific code, some EMI protection exists. But car thieves use jammers to steal cars, and they do not care if their jammer can affect your medical equipment.
By using the wireless extension of foot switch, you would save the 1-meter cable but expose the medical system to interference. Is it worth of the risk?

Technically, you can and should check the environment by a spectrum analyzer before installing your wireless system. But any interferer can come later and may cause damage.

WiFi and Internet now penetrate all medical facilities making all patients vulnerable to hacker wrongdoers. What did you achieve? GO BACK TO WIRES if you want to help people, not to risk their lives!!!

 

[chuckey]

This reminds me of UK Hospitals some years back. They forbad the use of mobile phones because they could interfere with hospital equipment. They overlooked the Doctors paging systems!!!
I do sympathise with the use of a RF link, cables on the floor are a hazard and get damaged. On the other hand a RF link requires a remote battery which will be flat when required. Could be useful to have a rechargeable "pocket" on the machine where the foot switch is stored and charges its battery (if the staff remember to leave the kit plugged in).
Frank

 

[vfone]

Each country has its own interference regulations.
In US each medical device that use non-licensed ISM (Industrial, Scientific, Medical) bands must accept any interference from primary users of the frequency band, under FCC Part 15 rules:

https://www.ecfr.gov/cgi-bin/text-i...rgn=div5&view=text&node=47:1.0.1.1.16&idno=47