Getting there~
For a variety of reasons, progress has slowed to a crawl and in some areas, I have shifted into reverse.
We had a rough beginning (including a temper tantrum) but so far I am happy with what I've thus far accomplished.
I decided that it was time for another status report, having just recently finished another stage of development.
While it's not what I initially wanted, I have settled on a mostly final case layout.
I present to you... the results of haphazard design and poor planning.
https://i.imgur.com/6rDwD9u.jpg
Dimensions:
133mm*67mm*37mm
The board is the ASUS Tinker board, but I will be moving back to an RPi3b due to technical difficulties.
However, for the time being, I only have stats on the tinkerboard.
After maximising all four cores to 100% within this mostly sealed case, the tinkerboard achieved a modest 8.4 Gigaflops of processing throughput on the CPU.
For comparison, a modern gaming console achieves about 100 Gigaflops via the CPU (and up to ~1800 via the GPU, which actually matters more)
So with this stress test, a natural outcome was a severe rise in heat generation.
With little more than passive cooling in a stagnant environment and an ambient temperature of 23℃, the onboard temperature sensor reported a peak of 76℃ after a mere 10 second stress test.
So what am I currently focusing on?
Currently I am working on (i.e. learning about):
- Battery management and load balancing.
I wish to utilize two 18650 Li-Ion battery cells to power the unit. This presents a few challenges. First, I must incorporate a DC-DC step-up converter which is capable of 3Amps or more. I also require a charging circuit, which may need to be external.
Additionally, I need to ensure the system can safely power down in the event of a low battery as well as be turned off and on via a Momentary NO SPST button.
- Heat dissipation.
Although it was an extreme use-case, 76℃ is out of the question. Ventilation is a requirement.
I have experimented with Peltier cooling, but this presents a major issue with condensation.
It may bring me below ambient, but its highly destructive to turn atmospheric moisture into actual water droplets. A single drop of water could destroy the entire system!
My current plan involves a 38mm hole above a custom made Aluminium heatsink where I would install a maglev directional blower (salvaged from a laptop).
Ideally, the fan would create a negative pressure environment, but further experimentation is required.
I have also consulted the Raspberry Pi forums regarding the possibility of adding a "GPU"
I am awaiting replies.
So what does work as of right now?
Well for now, all the Ren'Py games and similar test projects I have tried on it using the "Raspbian" operating system on the Pi3b (and Tinker OS on the Tinker board).
I have not yet had success in archiving a built Ren'Py program on a Raspberry Pi, but I have via the Tinker board, albeit compiled without the necessary hardware accelleration.
2018 Update:
The major work has been completed, all that's left now (hardware wise) is powering the device. I've tried many ways to power the device from many different kinds of batteries, but so far nothing is adequate to my liking.
The experimentation continues~~
A video of the device in use may be coming soon(™)