141–150 of 166 posts
We could have pretty decent $8 Linux machines, with USB, screen, touch, audio, MBs or even GBs RAM, if there would be some standard way to sideload fresh GNU/Linux onto billions of retired Android devices.
I thought you could root them and install Linux? But yeah, we need to recycle these phones by making them home servers, etc.
Earlier quoted context omitted.
AFAICT your home-grade wireless router / AP will start having trouble when you have dozens of Wi-Fi devices actively working in your home. ZigBee is somehow more resilient. It's also much lower energy, more comparable to Bluetooth, but much longer range: the sweet spot for smaller battery-powered devices. OTOH I remember that ZigBee is somehow more buttoned-up than BT and even wi-fi, so it's not commonly seen on like…
You don't need to connect dozens of devices. Esp32 can communicate as a server or a client so you can directly connect them without getting the router involved.
Do they all talk to each other in a mesh network, or do they all connect to your router in WIFI infrastructure mode?
We could have pretty decent $8 Linux machines, with USB, screen, touch, audio, MBs or even GBs RAM, if there would be some standard way to sideload fresh GNU/Linux onto billions of retired Android devices.
Earlier quoted context omitted.
You don't need to connect dozens of devices. Esp32 can communicate as a server or a client so you can directly connect them without getting the router involved.
Say, your house has 15 light switches on esp32 running Tasmota. Do they all talk to each other in a mesh network, or do they all connect to your router in WIFI infrastructure mode?
> ESP-WIFI-MESH is a wireless communication network with nodes organized in a mesh topology using the simultaneous AP-STA feature on Espressif SoCs. It provides a self-forming and self-healing network, with ease of deployment. The network topology of ESP-WIFI-MESH can scale up to 1000 nodes in large areas.
https://www.espressif.com/en/products/sdks/esp-wifi-mesh/ove...
https://randomnerdtutorials.com/esp-mesh-esp32-esp8266-painl...
---
I didn't know that home WiFi routers have difficulty with more than a dozen connections, but I imagine ESP MESH could be a way around it, where a few devices connect to your router and act as access points for the rest of them.
Earlier quoted context omitted.
Just as a semi-random example, NXP has the i.MX series[1] with one or more application-level cores alongside a microprocessor-level core. You can get something like the i.MX 8M Nano[2] with 4x Cortex-A53 and a single Cortex-M7. Another "big-player" option is ST which has the STM32MP1[3], which features a single Cortex-A7 alongside a Cortex-M4. [1]: https://www.nxp.com/products/processors-and-microcontrollers... [2]:…
NXP's software support for the heterogenous ARM cores is abysmal. I had to abandon an architecture on the iMX7 because their RPMSG drivers were simply broken. Documentation and examples were multiple-years old and their FAE support came down to "well, the examples work." Except they didn't. Perhaps it's better with the newer BSPs on the 8, but I wouldn't be too quick to jump back into it.
Earlier quoted context omitted.
RPis are used as embedded controllers and such instead of a custom solution, which is why they are so hard to get right now -- many companies based their products on them when they were plentiful and now get priority over end-users for distribution. It is (or was) kind of a scandal as RPi's self-mandate was to provide cheap computing devices for learning, not for businesses to make products.
I've heard a rumor too that the rpi foundation is having a legal spat about that part with Broadcom right now too. Broadcom is pissed that their chips they were using as a tax right off are being sold for profit. That's why you can get RP2040 boards like the Pico no problem; they don't contain Broadcom IP blocks.
Earlier quoted context omitted.
I'm a bit over Raspberry Pis at this point. They're impossible to find, and their performance is terrible. I tried getting back into one of my Raspberry Pis from scratch just earlier today, and even with setting up the OS from scratch and the most up to date version, it was unbearably slow. So slow as to be unusable for even the most simple tasks. So that kickstarts forum hopping trying to figure why, and there's lau…
By the time you get a Rpi 4, a decent power supply and an external SSD, it's usually around the same price as a mini PC which you can get with a 7th/8th/9th Gen i3 or even i5 with everything included. I get that the Rpi will use less power, but I imagine many people will be like me and have it overclocked to 2.1ghz, and my heatsink was pretty warm all day long. I've recently picked up a Optiplex 3070 with a i5 9500t…
I wonder if it is able to power on AA battery?
Typically recommended are lithium iron phosphate (LiFePO4) or lithum polymer (LiPo) batteries, both of which have higher capacity, better discharge profile, and can be recharged (the latter while the device is in operation).
I wonder if it is able to power on AA battery?
Unfortunately it has no sleep mode (the supported power-down modes erase the main RAM, leaving only 64KiB region, so it's unusable for suspending of the booted-up Linux), so it will last a few hours at most.
This is a common problem with almost all of such boards. And we see great power management is definitely possible: Android phones can suspend to milliwatts for a decade. But there is no support in this hardware, where you can run "normal" Linux, not Android :(
While this is "technically" a "Linux computer", in practice with such a small amount RAM the name is a stretch.
- processing data from a marine radar (it streams individual A-scopes as UDP stream), aggregating the sweeps into a .png image, denoising and uploading and handling some related logic (antenna tilt, gain settings)
- weather station pulling in data via serial/GPIO/... and publishing them as a webserver (lighttpd) and uploading them via OpenVPN to a cloud storage; firmware in the sensors can be easily updated and debugged remotely because the system runs avrdude and openocd
- emergency serial console - connected via USB to serial adapter to server, and you can SSH into it (again through OpenVPN/Wireguard), open a serial terminal or power-cycle the machine
- LoRaWAN gateway
And the best thing is that all this was written in Python! (with occasional C functions where native performance is required) So you have all the comfort of a high-level language and a full comfort of a standard Linux stack (though a bit limited because it is Busybox).