Webserver - Gazebo Equipment Box Layout

[TerryJC]

Attached is the first draft of the Gazebo Equipment Box Layout diagram. Only the first sheet is relevant to the March 2018 installation, but Sheets 2 and 3 provide an idea for how to add the Gazebo Pi electronics later.

[Penri]

Terry

OK with layout, will drill box and make up base board next week when I'm back.

Can you provide a list of the voltage and current requirements for the various items we may put in the box, please.


Hwyl

Penri

[TerryJC]

Penri,

The PSU Brick will be the only device requiring an external PSU I/P and all of the devices will be driven from it. The rated DC I/Ps for the electronics are:

• Antenna - 12 V, 1 A.
• Ethernet Switch - 5 V, 0,6 A.
• Raspberry Pi Zero - 5 V 0.7 A (typical, when lightly loaded as we will be).
• Interfaces Board - TBD depending on the design, but should be considerably less than 0.5 A at 5 V.
• Power for Sensors.
• Power for the Gate Valve actuator.

Clarifying the current I/p requirements for the last three items, I'm assuming that we would have the standard two sensors with a serial interface as discussed, so whatever the Tri-State Bus chips need, plus the current needed to drive the valve actuator.

I think that 3.3 A at 12 V should be sufficient, but we will obviously need to test the system in action and if necessary buy a more meaty brick.

[TerryJC]

Updated Box layout, as agreed this morning.

Any comments; please let me know.

[TerryJC]

This morning I changed the connector on the end of the 12 V PSU Brick (ex Samsung Chromebook; now dead) to suit the TP-Link PoE Injector. Before I started I compared the voltage and noise from this brick and the TP-Link supplied one for the PoE. Result:

• Chromebook Brick - Rated 12.0 V @ 3.3 A; actual O/P 12.5 V with approx 30 mV of noise.
• TP-Link Brick - Rated 12.0 V @ 1.0 A; actual O/P 12.07 V with approx 110 mV of noise.

I powered up the system and was able to connect to the AP with a good strong signal. I don't expect that the extra 0.43 V from the brick is likely to affect the AP much and the lower noise level should help with signal fidelity, so I think we a good to go.

I'll bring it along when I come in tomorrow afternoon so that we can fit the system as soon as we have a bit of time.

[Penri]

Hello Terry

I've found 3 shortish Cat5e patch cables amongst the stuff I've accumulated, they all test out OK. I'll bring them to WMT in the morning.

Hwyl

Penri

[TerryJC]

We'll have a surfeit then. I've ordered three at 99p each.

[Penri]

I was about to do the same but decided to root around to see what I had "in-stock" first.

[TerryJC]

It doesn't matter. These are very short - 25 cm. They'll be useful for other things.

[TerryJC]

Two 25 cm Cat 5e patch cables fitted yesterday.