What Should I Do With a Second Raspberry PI?

I have an existing Raspberry PI 4 running solely on an SD Card, providing my InfluxDB / Grafana setup and supporting a Conbee2 Zigbee stick for my IKEA and Philips Hue Zigbee switches, plus a few minor administrative functions.

I recently purchased a second rpi4, sd card and 512GB ssd. While I am starting to formulate my own plans and have my own intentions of what I will setup software-wise, I am interested to put out the question for others to comment on, not just for my own benefit. Throw out ideas and links to other threads that anyone may find useful, not just me, I e. What should I / anyone else use a second rpi4 for?


This has nothing to do with home automation, but I have a second pi on my office desk for development/testing/experimentation purposes

Another pi is running a custom program in my virtual pipe organ console. It controls relays for the DC power supplies, console lights, main PC control, etc. as well as monitoring and generating MIDI codes to control various things. I want that to work all the time so I don't do any development or tinkering on that one.

I used to have PiHole and NodeRed running on another pi, but I moved those to Docker containers on my NAS as it's always running and is very reliable.

Really, PIs are so inexpensive, it can't hurt to have one or two on hand for tinkering in addition to those that do actual work.

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Certainly outside my use cases, but exactly the kind of ideas I was wanting to promote.

I do like your approach to separating dev / testing vs production, certainly something I want to get to, maybe not with this addition, maybe with a third.... or fourth... or.... :slight_smile:

Given that the Rpi4 now boots/runs from an USB drive, curious as to know why you chose to (stilll) use a SD card.


Not sure why your wouldn't use a SD card. Thoughts?

SD Cards are notorious for wearing out much, much quicker than a SSD. Thus, many users have chosen to boot and run Raspberry Pi computers from a USB3.0 connected SSD for long-term reliability. There are some high endurance SD cards, often favored by dashcam users for their increased write durability. I would only run a RPi using one of those SD cards. Here is an example of a well-rated and reviewed high endurance SD card.



Yeah, I had read / heard the same as what @ogiewon explained and that is why I also bought the ssd. I just want to think through what I want to do, do I transition InfluxDB and Grafana onto the new one with it booting off the ssd, or set it up as a small utility /admin pi I want to setup for things like backups, vpn, etc, having it boot from the sd card but storing various files on the ssd from both pi's.

Here is one of the Youtube clip I watched on this:

This is the Sandisk SD Card I purchased:

any *nix project you can think of, throw it on there. want to play with HA or node red? load it up. want to make your TV fancy with LEDs? load up hyperion. want to cut down on ads you get? load up pihole.

i never used a pi for stuff, just have used *nix VMs to do things

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As in NixOS? First I've heard of it... Have been thinking about venturing into using Docker, but haven't made the plunge yet myself.


Ah, you were simply using * as a wildcard, I understand now. And you're right, they are great for small projects, and the fact that most of those projects have instructions online centred around *nix is what drew me to getting one.

I'm a big fan of WireGuard VPN... works great!!!

Also found this case - Argon ONE M.2 (not to be confused with the "regular" Argon 1)..



Before I switched to HE, I ran two ISY 994 units for my home automation. That required me to run a RPi with each unit just to have something as simple as a connection to my weather station (or another unit that company sold, at a price equal to their 994's price). Since switching the the far more capable HE, I now find myself with extra RPis laying around as well. I've already built a Plex media server with a RPi 4, so I think I'll try to create a weather web camera with one of the 3s. I could run a RPi Zero, but I'd like to have the extra processing power of the 3, and I don't have a Zero just laying around. I'll need to solve the weatherproof housing problem (likely easy) but the bigger problem will likely be power, as I want to place the camera at a location where no power exists and run it on solar and a battery. Hmmmm... Ideas welcome.

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It's a nice problem to have, given everything going on atm....

Can't say I've looked into it a lot myself, but would some of the conversations around UPS / battery backup be of any use in your situation? I.e. the battery powered option you hinted at....

Thanks for the tip. Had heard of wireguard but have never looked into it. Will take a look and compare to setting up a vpn via my Nighthawk router.

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It's very fast.. also check out this installation script:


You can install either OpenVPN or WireGuard.


Do you have any specific reasons for using the vpn? I mainly want the ability to get back to my network to perform administrative tasks when necessary. Though I do feel if I put the time and effort in I could achieve it through other means such as HE dashboards and other options, but ultimately a vpn gives total control for any unforeseen purpose.

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It is the only access point into my network. It's fast enough that sometimes I forget its running on my phone or laptop.

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I guess it is like saying why did you buy a Hubitat hub, both facilitate so many options it is hard to put a single or small number of use cases forward to justify the decision...


With the VPN I am not reliant on HE's cloud. Also since it's local and under my control I'm not paying for a subscription VPN service either.