On Sat, Sep 10, 2016 at 6:25 PM, Ian Stewart <ianstewart56(a)hotmail.com> wrote:
On a similar DYI theme...
What I've noticed in secondary school IT labs is 240VAC desktop units and
monitors connected to a main server by wired ethernet. They require an
air-conditioned room to dissipate the heat for the 30 x desktop units, the
teachers server and the heat from the students. This configuration involves
high costs in initial classroom re-fit and wiring installation, high cost of
initial IT hardware, high power consumption to run the lab, and (in theory)
the high cost of the proprietary operating system and software products.
My DYI for an IT lab would be along these lines...
28 x Raspberry PI 3's that use +5V.
28 x LCD monitors that use +12V with HDMI input and cable.
The RPi's are bolted onto the bottom of the monitors. So the students cant
take them home.
4 x rows of desks that can sit 7 students each at their Raspberry PI and
4 x DC power supplies from old desktop computers - one for each row.
For each row run +5v and +12V for the 7 x RPi3's and 7 x Monitor's in each
For each row have a wireless ethernet router for that rows RPi's to connect
to. This router will have a 1Gb/s ethernet cable back to a LAN card in the
teachers server computer.
28 x wireless keyboards and mice are kept in a lockable cupboard, the
students get them out, put them away for each lesson.
28 x breadboard kits with resistors, LED's, etc. are kept in a lockable
cupboard, and can be handed out to plug into the RPi's when teaching GPIO
port programming, etc.
Each student is responsible to buy and bring to class his/her own micro-SD
card that contains Raspbian and their data. (>$10 for 16GB)
Each student is responsible to buy and bring to class his/her own earphones.
(>$10, but they have probably already got a set for their mobile phone.)
The teachers server would have 5 x 1Gb/s LAN ports, 1 for each wireless
router and 1 for external connection to the schools LAN / Internet.
If you allow 5W for the RPi, and 20W for the monitor, then you achieve 25
Watts of energy consumption per student. This is 700 Watts for the classroom
(excluding the teachers server). This may be less than the power
consumption of the lighting for the classroom, unless they have already
switched to LED lighting. Air-conditioning of the room may be found to be
...Anyone got any design ideas and enhancements?
I would add the Raspberry Pi 7 inch touch screen.
costs around 140 dollars so increases the price of the setup. Use
power banks (super cheap from China). No power in classroom is needed.
New schools (RJHS) don't seem to have ethernet outlets. Chromebooks
everywhere (with a few macbook airs) and Chrome desktops scatted.