Know How...

Dec 14th 2017

Know How... 360

Networking Rock n' Roll!

Will regular networking cable burn down my house? How can I fit an entire music studio on my belt? How can I create a Raspberry Pi case that can do it all? -- All this on a feedback episode of Know How!
Although the show is no longer in production, you can enjoy episodes from the TWiT Archives.
Category: Help & How To


Premise Wiring
" Can we please get another networking 101 about how to install wired networks? We've seen premise wiring but we never really touched the differences in types of ethernet cable. More to the point where and how to invest money in cables such as plenum vs shielded, riser, in-wall rated, bare copper, stranded copper, solid copper, or sfp and sfp+? Do we future proof with Cat 6a, Cat 7, sfp+? What do we look for when installing wired networking? Should we use outdoor rated for exterior cameras or other devices? So many choices that boggles the mind so what, when, where, why, and how? Also how and where to shop? So +Fr. Robert Ballecer, SJ can Know How go over some of this?"  -- T NoHands
There's a LOT here... definitely for a future show, but there are a few things we can tackle off the top!
Plenum vs. Regular Cable
  • The "Plenum Space" is non-sealed space in a building. (The space between a roof and a drop-ceiling, or the floor and a raised floor)
  • We like to use those spaces for running cables. (Out of sight, away from power, good access to the entire structure)
We like to buy good, but inexpensive cables (Like this Cat 5e) ~$35
  • 4 pairs of unshielded-twisted-pair.
  • Can do 1Gig Ethernet for 100 Meters.
But there's a problem: Any cable you put into a plenum space is a fire hazard... ESPECIALLY as it ages. You can short out a pair by accidentally having it come into contact with a high-voltage source, and you've just set fire to your building.
That's why we have "Plenum Cable"
  • For networking, it uses the same 24 AWG UTP configuration. BUT... the jacket is a specially-formulated low-smoke, fire-retardant material. In case of short or fire, the jacket will melt around the short, but no lasting fire, and little smoke.
However... IT'S CRAZY-EXPENSIVE! ~$200
Cable Conundrum
  • Copper for 1Gig
  • Fiber for 10Gig
  • But FAR more important... conduit. Conduit makes EVERYTHING BETTER!

Can you inSPIRE me?

"I just watched episode 358 and I was a little offended that you titled it “Mancave”. As a full geek and a WOMAN, there was plenty of gear in the show that I would like to have in MY den. (I don’t call it my woman-cave because that always starts a bunch of immature giggling.) Specifically, I really like the Spire Studio that Jason showed us. As a musician myself (strings and percussion) I’ve been looking at an easy way to layer tracks. Any chance we could get a demo of how it works?
Thanks for the show, and PLEASE remember that you have audience members with TWO X chromosomes!”  -- Elizabeth Marten
Spire Studio (for prototyping songs) - my new favorite thing ($350)
We're going to preview the LiPi!
Project Summary:
We've done several RasPi projects this year that could benefit from an independent power source. (The TorPi, the Pi-Hole, The RetroPi) -- We want to create a power system that can act BOTH as a powerable power system AND an uninterruptible power system.
Project Requirements:
1. Must have a way to power the RasPi WITHOUT using the USB connector
2. Must have a way to switch from line power to battery power AND BACK without disrupting operation.
3. Must have a way to turn OFF power completely (to prevent draining the battery pack)
4. Must operate or more than 3 hours
5. NUC-sized
6. Should have a way to gracefully power-down the Pi
7. Must have a way to swap the SD card without disassembly
LiPi Parts
Power Calculations
  • ~5 Watt/Hours
  • Each Cell can provide (3800 x 3.7 = ) ~14 Watt/Hours
  • We have ~42 Watt/Hours of capacity
  • But we don't run down all the way... 30% is when the protection circuit will kick in. 
  • So we should count on 29 Watt-hours of USABLE power
  • 29 / 5 = Just under 6 hours AT FULL POWER
  • Shutting down WiFi/Bluetooth and not pegging 100% power should give us close to 8 hours.

Aluminum Pi 

"Hi Robert, I just watched the show where you mentioned you'll be leaving next year. Just wanted to send you something as a token of my appreciation for all I've learned from Know How. From 3D printers to quadcopters to Arduinos and Raspberry Pi's while I've mostly just futzed around with them, I've been able to use them to turn my son onto engineering and electronics at an early age, which has undoubtedly broadened his horizons (he's always talking about wanting to make robots when he grows up!).

Anyway, I made a few of these cases for raspberry Pi Zeros on my CNC mill and I thought it'd make carrying one on your travels a little easier. This is for the 1.3 version, though it'll fit a W too, just not sure how much wireless strenght will be degraded. Not that it really needs it, but a little heat past between the CPU and the little pad in the top should help dissipate heat through the case.

Anyway, thanks again for sharing your knowledge!"  -- Chris and (His Son) Vlad

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