@Shanan-Clark Yes. Theoretically you could build a "beautiful" Onion Omega Tower using
an Expansion Dock or a Power Dock or an Arduino Dock 2 (and an Omega2(+) of course)
and two (2) ADC Expansions - with 2 x 4 single ended (0..+5V) or 2 x 2 differential (-5V..+5V) analog inputs in total
I2C addresses 0x48..0x49
and eight (8) Relay Expansions with 8 x 2 relay outputs in total
I2C addresses 0x20..0x27
BTW I can imagine a little bit better (more robust) mechanical structure than that stacked tower since there are only five (5) connections / wires between these Expansions and the Dock - or even a bare Omega2(+) - namely the +5v, +3.3V, GND and the I2C SCL, SDA lines.
It's silent now... no wifi network detected (the Onion Access Point) and the connection via serial will only bring a dark empty console... Amber LED never flashed since I switched it on the very first time Mobdro App
I seem to have found a solution for this issue, or at least a work around that works for me: YMMV
I've merged in the OpenWRT repo (git merge -X theirs openwrt/lede-17.01) into my OnionIoT/source repo. That built flawlessly ! :). So we're running kernel 4.4.153 now. That's nice on its own (always recommended to keep up with LTS kernel versions!).
Anyway, the SPI problem persisted. Then I removed the original Onion patch file for the spi-mt7621 module (rm ramips/patches-4.4/9999-spi-mt7621.patch) and rebuilt the image. Now we're using the unpatched mainline SPI driver. Guess what: this seems to work flawlessly! :) I'm a happy man now.
I only did some quick smoke tests, so it could be other SPI stuff breaks because of the missing patch. On the other hand, there have been some commits to the spi-mt7621 module in June, so the mainline might just be the only thing we need.
Regarding the relays, maybe think about SSR (solid state relays). They're a bit more expensive but controllable with logic signals and available up to very high current - beyond 100A at mains voltages.
The AC one also generally offer zero crossing switching i.e. switch at the 0V portion of the AC cycle.
@Lazar-Demin Hello, i'm trying to solve this problem too, can you explain more specifically where the root of the problem is and what modules it affects?
I debugged and find in arch/mips/mm/dma-default.c struct dma_map_ops what consist NULL, do u fix it?
@Rogier-Lodewijks no, u don't need patch spidev, only spi-mt7621.c source file and it's in kernel yea. After this u can add cs-gpios in device tree, and spi device in node. Spi device can be spidev if u developing spi driver and u need its API. Thank you)