# Prerequisites for perimeter detect
**URL:** https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621
**Category:** ZYMKEY4
**Created:** [August 18, 2019, 9:44am UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621 "2019-08-18T09:44:02Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@therealburningman](https://community.zymbit.com/u/therealburningman)
#### Post date: [August 18, 2019, 9:44am UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621/1 "2019-08-18T09:44:03Z")
Hi! I’ve bought the Zymkey for RPI 3 and working on the Perimeter detect. Its super unclear, but I suspect a Protokit 4 is mandatory to actually use perimeter detect? If that is not the case. What do I buy/setup to get perimeter detect operational?
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### Author:  [@gnmckinney](https://community.zymbit.com/u/gnmckinney)
#### Post date: [August 18, 2019, 1:27pm UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621/2 "2019-08-18T13:27:09Z")
[https://community.zymbit.com/t/using-perimeter-detect/204](https://community.zymbit.com/t/using-perimeter-detect/204) - Check this tread.
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### Author:  [@therealburningman](https://community.zymbit.com/u/therealburningman)
#### Post date: [August 20, 2019, 10:32am UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621/3 "2019-08-20T10:32:25Z")
So. I don’t need a ProtoKit 4. Reading from that link. I am not a native English speaker, so did I translate this correctly?
and nominal length of 2 feet **(meaning max length?)**
What is 30 AWG?
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### Author:  [@gnmckinney](https://community.zymbit.com/u/gnmckinney)
#### Post date: [August 20, 2019, 10:56am UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621/4 "2019-08-20T10:56:52Z")
AWG is the acronym for American Wire Gauge, a diameter measurement and is equivalent to 0.2546mm.
I suspect the 2-foot (60.96 cm) nominal length refers to the loop distance for the sensing loop. Longer lengths could start picking up electrical noise and inadvertently trigger the loop triggers. Not a good thing (t) 🙂
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### Author:  [@therealburningman](https://community.zymbit.com/u/therealburningman)
#### Post date: [August 20, 2019, 5:23pm UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621/5 "2019-08-20T17:23:05Z")
Are there different trigger techniques? I’m new to this. Would be nice to have an idea of some loop setups.
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### Author:  [@gnmckinney](https://community.zymbit.com/u/gnmckinney)
#### Post date: [August 21, 2019, 10:06am UTC](https://community.zymbit.com/t/prerequisites-for-perimeter-detect/621/6 "2019-08-21T10:06:08Z")
I have not gotten to the stage of testing the tamper circuits yet (just received the hardware about a week ago). I am sure someone else here can answer your questions much better than I at this point in time.