RPi GPIO monitoring

[mik3y]

Spawned from issue #3: Monitor mode only listens to kegboards, but we've had some long-standing requests for RPI GPIO support. Add a trivial flow meter daemon for these pins.

[kerber]

I'm definitely going to keep an eye on how this turns out for you. I've done some cursory testing with monitoring an SF800 from GPIO as well as using an MCP23017 as a go-between. While I was getting good reads, my main concern was losing pulses while the CPU was busy with other tasks. With all the processing needed for the kegbot server, do you see this as a viable option?

[mik3y]

@kerber: Yeah, I'm skeptical about this architecture, but it's something we want to do just to cover all bases. (Similarly I think Android makes for an objectively better frontend than RPi, but some people want an all-pi system; hence Kegberry).

A dedicated micro -- KBPM, or even a cheap DIY one -- will have the advantage of being totally decoupled from whatever Linux us up to, as far as flow sensing is concerned. (Not to mention other features & portability..) That said, I've got an experiment to try.

[kerber]

I totally agree on the dedicated Micro. That actually feeds into something I've been wondering about the KBPM. What led to your decision to only read one flow monitor per atmega32u4? I've been running a few tests with a Leonardo (atmega32u4 based) and I'm having no problem polling 4 concurrent 1.2kHz pulsed lines. I could see relying on interrupts when you had other functionality on the micro, but those KBPM seem pretty dedicated to flow monitoring. Did you run into some design issue with that method that I've not thought of?

[mik3y]

Re: KBPM: It's mostly a board/connector space compromise. KBPM actually supports two meters (int0 and int1), and could support more (int3,4 and pin change interrupts) with a firmware change, assuming the pins are exposed.

Our product goals were to make a small (1" x 2") board, pin compatible with our RJ-45 KegJack; adding more connectors would have blown up the board size, assembly and BOM cost, etc, so we held back on it for "v1". After all, anyone interested in hacking a big board together can already do so with the firmware plus Arduino [Mega], and less-technical users can scale up with a USB hub. (We're working on a bigger board as a follow-on.)

[kerber]

Thanks for the informative answer! Will the firmware for the neg KBPM be posted, or does the Android app work with the current version of the Kegboard?

[mik3y]

Same firmware! Set target to Arduino Leonardo and it should Just Work™.

Production firmware is built against the Kegboard/Arduino repo -- a tiny fork that includes a few minor board-specific customizations (like the USB VID/PID) for a new kbpm Arduino board type. Also, kegboard_config.h will automatically disable a few options that would be no-ops (like the buzzer) when this board type is used.

[geokal]

Hi currently experimenting with some sort of the same project but with coffee ,raspberry as a server with flow meter (lower resolution than SF800 )on gpio and electric valve(teflon) attached on a big caffe dispenser through rpi.gpio python and does not seem as reliable as on an arduino. So can i upload firmware to an Uno R3 or i need a Leonardo?Thanks .Big thanks for sharing all these info and code!!!Keep On

[chrismeyersfsu]

I'm a bit confused as to if Raspberry Pi GPIO is now supported. Can you clarify the status?

[loganbest]

Also want to know an update here. Surely after almost 2 years something has come out of this. :)

[joel7269]

Any updates on this?

[kjones6197]

Was any progress ever made on this?