Congratulations, you are very funny. /s

I was actually considering something like “A new Raspberry Pi 5 is the best and most cost-effective option for my use case” to take advantage of Cunningham’s law.

• The drive can be spun down, and I’ll try to cache most frequent and recent files to SSD to save power
• Volts aren’t watts, the HDD uses 20W when spinning but <1 W in standby
• The home already overproduces solar so yes, we have cheap electricity at daytime, but we still have to pay some 0.40 €/kWh for the nightly use. Solar panels are a good investment but so is saving power regardless of production, otherwise one is robbing oneself of the grid buyback payouts. These are around half the cost of nighttime electricity.

Why Docker? I’m definitely not after scalability.

Yeah, that’s where it’s going now, the SSD arrives tomorrow. If the sale does not go through, I’ll keep the money or buy some microcontrollers instead.

I don’t think the TV does either

Edit: it does! I tested with the existing satellite STB (which I’ll be replacing with IPTV for cost reasons) but the only feature it can do is turn the source on/off, it does not pass the 0-9 or P+/P- key presses to it when in HDMI mode - it switches to the now useless analog tuner when any of them are pressed. Either way, I have a universal remote that I can program to send different codes for 0-9 and P+/P-, so that they are only interpreted by the USB IR receiver I install and not the TV.

Most MoBos allow programmatic fan control too, right?

I’m OK with a fan running when the HDD is spinning. To save power, a SSD can perhaps be used as a cache to minimize HDD usage time during file transfers over LAN or torrent.

Fujitsu Futro S740

Now that’s a good recommendation. I didn’t find any for sale around here but I can get an HP T530 that also idles below 10 W for 35 €. I’d need to buy an HDMI-DP adapter, plus an M.2 SSD or a wireless module (they use the same slot and there’s just one), the other would need to be a USB peripheral.

I have an official RPi 5V3A supply already, which can power the Pi 5 at lower clock speeds, which kinda defeats the point of buying it over the 4B, unless they are almost the same price (around 60 € used at the official store). I’ve been trying to contact someone selling a “barely used” 4B for 40 € but they haven’t responded yet.

All the use cases I need are well-documented on ARM by the RPi community. What issues do you think I’d encounter?

plenty of useful IO

It’s not that old or professional, unfortunately. It was a budget 15.6" one I got from a relative. Only two USB ports (one is 3.0), Ethernet, HDMI, headphone jack and DVD±RW drive. It’s underwhelming but not that I need much more. It can’t even do 4K but the TV is 1366x768 so that’s OK too.

The device will run 100% of the time as a torrent client and NAS so I don’t really need to solve the power-on issue, long unplanned outages are rare and I can probably bridge the short ones by going low power and waking up every hour.

I already have two USB adapters for SATA, they just require Molex connectors so I need an entire ATX PSU right now to power the drive. They will be enough to get the setup going before I measure how much power I actually need and solder an appropriate 12V and 5V supply to the cable.

I have an old laptop that is used as an HTPC but not much anymore. It runs Lubuntu alright but it needs an upgrade to an SSD. I think I’ll shell out a little extra for 512 GB rather than some 64-128 GB the Linux+software install needs, so I can cache media there and reduce the HDD utilization. A hack will be required to bypass the lack of “power on AC” in the BIOS, probably removing the lid magnets and wiring the power switch to an Arduino or something to facilitate a restart after a power outage (long unplanned outages are rare though so I might get away without that right now). The idle power usage will be some 10 W but I can live with that.

I wonder if there is an advanced BitTorrent client that can import my extensive qBittorrent library and respond to supply/demand while minimizing the HDD’s duty cycle… for example refusing to spin it up just to seed public or overseeded torrents, and only spinning it up to copy the contents to SSD for files that are on demand, or write completed downloads from SSD to HDD.

USB-C definitely can handle a 768p monitor plus playing video from disk and 100Mbit Ethernet, it’s just that most phones under my 100 € budget (cut short by the dongle) don’t even have 2.0 OTG capabilities because they’re basic ones for seniors. The only hope to get a discount on the good ones are those with a semi-busted screen but I’m not relying on that to install Linux.

The Raspberry fits in the budget, and there is a guy selling one for 40 € but he’s not responded yet…

Also what’s the problem with the battery? It still lasts an hour with the screen on so it’s not trash yet… I’m into electronics and repurpose old Li-Ion cells all the time, including 15 year old Nokia BL-5Cs and they’re alright, they don’t spontaneously develop shorts and are protected against electrical abuse. It’s the alkaline cells that cause havoc (corrosion) if left unused for years. If need be, I can just replace individual cells (I think they are 18650) from a power tool found in trash. Of course, I would get rid of bulging or overheating cells if I encountered them.

You mean x86 is more memory efficient? I guess I’ll try the 10yo laptop first, it’s the cheapest option for the time being. It has 4 GB of memory too but I really don’t think a single browser tab playing 720p video (the TV is 1366x768), a torrent client, Home Assistant and a file server will even max it out. I can reserve swap on its new SATA SSD just in case. It’s a decent HTPC already (save for boot times and the clumsy power button, which I can solder a remote switch to) and that’s on an HDD!

Yeah but at that point I can just use the 10 year old laptop I have lying around, since size is not really a priority. I have installed Lubuntu on its HDD and it’s been so-so as an HTPC but I think it will be alright with a new small SATA SSD. It might need a lid + power button hack (using simple electronics wired to the corresponding connectors?) though because the BIOS has no “power on AC” option to get it back up after an outage.

It’s around 3x the budget, which is a greater dealbreaker than a USB3.0-SATA adapter plus 12V source, all of which I already own.
Also, the R1 name sounds too AI-y to me (Rabbit, DeepSeek) but that’s not really relevant.

Many? They’re going to be idle most of the time, I don’t think I’ll even need a Pi 5 over a 4B

Not for the budget. I have some spare phones but no USB-C ones and there is no way this all works over microUSB, even with MHL.