Posts made by Andrei Railean

Hi @Carlos-Sancho how do you control your OLED? do you use oled-exp or related python/c libraries or did you have to write your own program to communicate with the display?

Hi guys, I did a quick talk and a demo of my Onion Omega setup at a meetup in Sydney.
I showed off my set up with one omega used as an access point and a MQTT broker and two others connecting to it for WiFi and MQTT. One of those was a pressure and temp sensor pushing messages to the queue. The other was fetching and displaying this data on the OLED expansion. All of the work is done in a few bash scripts that use i2c, oled and mosquitto command line tools.

http://www.meetup.com/OzBerryPi/photos/26969207/#449991484

Thanks for the update and the change log. I guess now that kmod-bluetooth is in, we'll have a quick tutorial on using the BLE dongle. Can't wait.

Here's some more code I found on the web for configuring openwrt to act as a bridge

https://bitbucket.org/pklaus/openwrt-configurations/branches/compare/TP-Link_TL-MR3020%2Fwisp TP-Link_TL-MR3020%2Fdefault#diff

https://bitbucket.org/pklaus/openwrt-configurations/src/c6186f9106c7?at=TP-Link_TL-MR3020/wisp

Thanks @Lazar-Demin. I was trying to avoid dropping down to C level just yet.
I did see that the C library allows more flexibility in reading and writing bytes over i2c.

I'll start another thread when I get into Python i2c interaction. Will check out your code.

Looks like you're on the right track.
Here's a bit more info. https://wiki.openwrt.org/doc/recipes/dumbap
This doc also talks about disabling DHCP and the firewall.

I played with it last night but couldn't get it to work yet. Was configuring it over serial and trying to connect my computer to Omega acting as Dumb AP. Will try again later.

Looks like you need to disable DHCP on the omega and let it act as just an access point without creating a separate network.

My experimental setup is similar to yours:
ADSL Router --> WIFI 1 --> Onion A --> WIFI 2 --> Computer and Onion B

I've considered in disabling DHCP on Onion A, but didn't because sometimes I find myself in a situation without internet or main router, but still wanting to hack on the Onions. Having Onion A be my router and access point is quite helpful in those situations.

Hi @Boken-Lin, the main limitation of i2c-tools for me is that the binary i2cget cannot read more than 16 bits in one go - i need to read 24 bits, for example. The fact that it's endianness cannot be controlled is a bit of an inconvenience, but can be worked around.

I am yet to interact with i2c via python, mainly because py-smbus parts of i2c-tools are not compiled and not available for install via opkg. Hence my need to get my hands dirty with buildroot and compilation.

Hi peeps, this is just a heads up that i2cget command-line tool is little endian. This means that when you request a word from it, it assumes the first byte is the least significant one. So if you're reading from a sensor and it gives you two bytes in sequence, say first 0xAA then 0xBB, i2cget will output 0xBBAA.

My sensor is big endian, so I end up having to flip bytes every time I read a 16bit word. In my case i need 0xAABB from above example.

It's probably the case that i2cset is little endian as well. I haven't had to write any data via i2c on command line, so cannot confirm.

fair enough @Kit-Bishop, i thought you were just trying to compile i2c-tools.
can't help you with compilation yet as I haven't tried setting up a buildroot yet. intend to get to that soon as I'm hitting limitations with stock i2c-tools and need to go to writing code in C.

i2c-tools are either already installed on your omega or can be installed with opkg. why do you need to compile them yourself?

opkg update
opkg install i2c-tools

How does it look when you connect to it on serial console via USB? can you run wifisetup?

Omegas have this behaviour where every 10 minutes there's a script running that checks if wifi connection is present. if there isn't, it creates an access point based on ethernet mac address .

When I upgrade using oupgrade or through the browser my network gets screwed up. My omega is set up to connect to the local network. Omega's access point is disabled. After upgrading, the connection doesn't start up automatically. That built-in script that runs every 10 minutes tries to create an access point breaks my wifi config by editing my config file and leaving it in an unusable state.

I have a USB stick with omega's wifi settings and copy that over after each upgrade. Basically, i keep a backup of /etc/config/wireless

tried running --force-depends and promptly ran out of space as expected. now cleaning up.

I think you need to try an avoid using python-pip unless you can get it to use a USB drive, @Vitalii-Topoliuk . if you're running out of space just installing python-pip, imagine how quickly you'll run out of space trying to install your python packages and all their dependencies on top of it.

my bet would be on trying to use pure python scripts and upload a self-contained project that doesn't need installation or compilation. alternatively, I would try building it in a buildroot environment and transferring it to the omega with all the dependencies resolved.

I've tried installing python-pip as well and ran out of space because it pulls in way too many dependencies. I wouldn't even know how to compute the space it's going to need, but i suspect it'll be much bigger than the available space on the omega, even with /www removed.

Looks like with a bit more hardware you can run SPI over I2c

NXP SC18IS602BIPW: I2C-bus to SPI bridge

I got my Bluetooth dongle today.
Looking forward to official instructions on how it should be used.
Tried installing the bluetooth kernel extensions and am getting errors:

opkg install kmod-bluetooth_6lowpan
...
Collected errors:
 * satisfy_dependencies_for: Cannot satisfy the following dependencies for kmod-bluetooth_6lowpan:
 *      kernel (= 3.18.20-1-7bed08fa9c06eb8089e82c200340ec66)

I think I need to try using opkg --force-depends install the extension, but i'm no hurry to do it as I don't quite know what to do with Bluetooth once I have it all working.

PS: I'm running Ω-ware: 0.0.5 b234

Thanks @Zheng-Han

Hi Guys, are there any electrical and clock specifications for docks, expansions and the omega itself?
I'm interested in typical voltage and allowed ranges on GPIO and i2c pins.
As there are 4 different voltage headers on the expansion (1.8, 2, 3.3, 5) it'd be good to know what voltages are used to communicate to other expansions.

Knowing tolerance ranges is helpful to know what external peripherals can be hooked up and what extra circuitry may be needed to support them.

I don't have an oscilloscope to measure any of this.

Not sure why pull-up resistors are not needed for 2 and 2.5v.

There's voltage on the 3.3v line, so I wouldn't call it an input line.

I think the discussion of the future of community should be moved out of this thread. Either into a category of it's own or at least a thread. I don't think NodeBB structure encourages good structure. Perhaps, the roadmap should be managed in Github issues - this way, even if there's not much future planning, you at least get a way to construct a changelog and explore all associated conversations.

To begin with, I would recommend you guys to familiarise yourselves with the work of Pieter Hintjens and his efforts on building the ZeroMQ community. Here's one of his recent articles that may be relevant: Ten Rules for Open Source Success. There are quite a few of his talks on YouTube where he talks about community building.

Main thing to do now would be to publish the roadmap - you keep referring to it in many posts. Then you need to reach out to the community for help in bringing that roadmap to life.

At this stage, I think that the software side of things is something community could clearly help with. Things like building and porting OpenWRT packages to omega and configuring systems for particular use cases. As an example, for many answers to my questions I go directly to OpenWrt website as they have a decent structure and tons of content. Something similar can be achieved with a system like GitBook. I personally believe that if it's not possible to comment on a piece of documentation - it's dead. All docs must be searchable.