You get case, fan, switch, fan PSU and bags of nuts, bolts, washers and wire. What could possibly go wrong?
In this case you get a programmable power supply able to give you up to 50v at up to 20 amps output.
But doesn’t that seem a bit daft, needing a power supply to feed a DIY power supply? Nowhere near as daft as it seems – read on – it gets a lot better…
These are just thoughts – hopefully someone is going to write in and tell me I have it all wrong.
As regular readers will know I have reviewed (and messed with) MANY small Pi-type boards including the Raspberry Pi, Banana Pi, NanoPi etc etc. I’ve also had a go with some power supplies and even made up my own solutions at board level. We’ve had discussions about the issues with FLASH and minimising writes and so mentally it all seems to be coming together. What is needed for our home control central control projects is:
A cheap SBC with enough RAM to be able to lose some for LOG2RAM and buffering for datbases etc to utterly minimise writes to FLASH – so ideally maybe once per day, stuff in RAM would be written to FLASH.
To go with the above then – clearly a power supply is needed that will not fail – i.e. with battery backup.
Sure, if you through enough money at this – there are solutions for everything but at a budget?
Firstly, RAM – just not enough – some of these boards have 256Meg and 512 Meg - enough for normal use but if you start stealing some of it to run Log2RAM and RAM-buffering databases (RAMDISK) then you start to run out – it seems to be that 2GB of RAM would be a nice figure yet I’m only aware of a small number of these boards that have this much – if memory serves me well, the Odroid C2 – and a board I’ve only just recently heard of – the FriendlyArm NanoPi K2. There will be one or two others I’ve long since forgotten. The Raspberry Pi people for example apparently have no intention of moving to 2GB in the near future. We see people using these boards for media management yet if you look at the notes from the designers of such software they usually suggest 2GB minimum RAM! I don’t do media management but our chats about FLASH have me using Log2RAM and RAMDISK and depending on your needs you could be looking at losing 512Meg or your precious RAM.
Power supplies – especially important given the above - recent testing has shown that we don’t seem to have a single low cost unit available that can handle the battery going down to zero – and recovering gracefully while the the load is connected or having to press a button or some impractical manual interjection – and bearing in mind that several of the better boards need 2amps+. Looking back through the blog there is not one – there’s one on Kickstarter but that is now way, way late in appearing and for all we know THAT might not do the job.
What are people’s thoughts – am I talking nonsense? Am I missing some products? What do you think? Do people have low-cost solutions I’m not aware of?