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- The Raspberry Pi PingER MA must be robust and reliable. It needs to run for months to years with no need for intervention. This still needs to be verified, so far the Raspberry Pi has successfully run without intervention for over a month. This has included automatic recovery after two test power outages.
- The important metrics derived from the measurements made by the Raspberry Pi should not be significantly different from those made by a bare metal PingER MA, or if they are then this needs to be understood.
- The Raspberry Pi needs to be able to run 24 hours a day with only solar derived power. Let's say the power required is 3W at 5V or (3/5)A=0.6A. If we have a 10,000 mAh battery, then at 0.6A it should have power for 10Ah/0.6A ~ 16.6 hours. Then we need a solar cell to be able to refill the battery in a few hours of sunlight. Let's take a 10W 20W 5 V solar panel = 10(see http://www.amazon.com/SUNKINGDOM-trade-Foldable-Charger-Compatible/dp/B00MTEDTWG) = 20/5= 2 4 A solar panel. So initial guess is 10A-h/2A 4A = 2.5hours. But inefficiences (see http://www.voltaicsystems.com/blog/estimating-battery-charge-time-from-solar/) of say 2.5 extends this to 12.5 hours. We need to reduce the charge time to half of this (say 6.25 hours), so let's use a 20W 5 V panel (see http://www.amazon.com/SUNKINGDOM-trade-Foldable-Charger-Compatible/dp/B00MTEDTWG) hours.
We define the important metrics measured by PingER as being the minimum, average, median and jitter of the RTTs, the packet loss, together with the reachability (i.e. a target host is unreachable when no ping requests are responded by the target host). These are the main metrics that impact applications such as throughput, voice over IP, streaming video, haptics, and estimating the geolocation of a host by pinging it from well know landmarks. Such differences might result in significant discontinuities in the metric measurements if we were to change the monitoring host from a bare metal server to a Raspberry Pi.
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