Selecting the best objective solution is not always easy, let's face it, we want to mess with a Raspberry Pi. This project is not about doing what we want though (see the five W and the needs), so if in the end the selected solution does not meet the functional specifications in a satisfying way and there is a better alternative then the workstation is going to be discarded in favour of the better solution.

That being said, we select the Raspberry Pi 3 workstation as the best objective solution.

The university we work at has a computer recycling program, the people managing this program were kind enough to provide five 20" screens with integrated speakers (Philips Brilliance 200P4SS/00), mouses and keyboards for free for the cause. However even though the screens are flat they are very heavy: about 7.5Kg per screen.

So the current cost of one computer:

• Screen: $0
• Power cable: $0
• Keyboard: $0
• Mouse: $0
• Raspberry Pi 3: $40
• Micro SD card (8GB): $10
• HDMI-DVI cable: $5
• 5V power supply: $5
• Micro-USB cable: $1
• Audio cable: $1

Total: $62 per workstation.

For the weight budget:

• Screen 7.5Kg
• Peripherals: 1Kg

Total: 8.5Kg per workstation.

According to our previous formula:

That's a decent dollar to computer ratio of about 100 and will cost about $300 total. It's not the $50 and 3Kg per computer we hoped for, but it's good enough and yields about 0.1/0.25 of the global performance (40% of maximum performance) - see the Transport Costs log.

It's also important to mention that at this point the problem of intermittent power failures that can corrupt the RPi filesystem is not yet solved, an UPS is an expensive element, but there are other ways to mitigate this issue.