Galvanic Isolation of 1-Wire Devices (Direct Power)

With an Arduino, some DS18B20 temperature sensors and a Si8600 …
↓↓↓ Complete description, time index and links below ↓↓↓

We’ve already galvanically isolated an SPI bus (link below). With all SPI bus lines being unidirectional and chips for the job readily available that was kinda easy. The 1-Wire bus however uses only, well, one line. And that is bidirectional.

It seems there are no chips available for the digital isolation of 1-Wire buses. But there’s another bus using a bidirectional line: I2C. And digital isolators for the I2C bus are available. Maybe those will work for 1-Wire buses too.

00:00 Intro – why would you want to galvanically isolate a 1-Wire bus?
03:17 Searching – for a digital isolator that can handle 1-Wire
06:31 Si8600 – does the job
08:26 Isolating 1-Wire – with the Si8600 on the breadboard
11:38 Isolating DC – with an unregulated, isolated DC-DC converter
13:10 Schematic – nothing much to it
14:49 Code – just a quick look
16:29 Bonus 1 – how bidirectional digital isolators prevent latching
22:48 Bonus 2 – input/output filtering for the DC-DC converter (unnecessary)
29:58 Wrap-up – better safe than sorry

#robertssmorgasbord #tutorials #tutorial #how-to #bus #isolation #galvanic

[KSD]

방폭전기기기에서 갈바닉 절연을 설명하시오.
갈바닉 절연이란 본질안전 전기기기 또는 본질안전 관련전기기기 내부의 2개 회로 사이에 직접적인 전기적 신호 없이 또는 전력이 전달되도록 한 구조를 말한다.

[andymouse]

I have need of some DS18B20 sensors coming up, and I will referencing this series of tutorials, its interesting using the I2c Bidirectional data lines in this manner...cheers.

[felixcat]

Who can figure what this poster is talking about?

[davidrichardson]

The LC filter at the input to the DC-DC converter probably rolls-off the harmonics of the converter switching frequency all the way up to VHF. Your breadboard construction would never pass an EMC acceptance test, breaking all the rules of good EMC design practice. The oscilloscope probe lead is also unsuitable for noise measurements except perhaps at audio frequencies, looking more tike a 1-metre antenna with a loop on the end at HF and above. I still would never play with my Arduino connected to a long external line when a thunderstorm is about (lol).