Posts made by Martin Oberg

It seems like every few days to a week I can't connect to my Omega. I have a node web server running and I get a "ERR_ADDRESS_UNREACHABLE" message from the browser and a "No route to host" error when I try ssh. I can, however, switch my computer's wifi to the Omega's network and gain access both through the browser and ssh via its address of 192.168.9.1 (not localhost or 127.0.0.1). But it still refuses to connect upon switching back to the home network.

I can see the Omega when I log on to my router - I've also assigned it a static IP address.

So far I've been restarting the Omega to get back to normal, but this doesn't seem like a good long term solution. I just thought today to connect via the Omega's wifi network, so now at least I have hope to figure out what's going on if I can get help for what kind of diagnostics to run.

The code is now in a shareable state. Here's the github link. I hope it's easy for people to adapt to their projects. Let me know how it works.

You may remember webkeezer, the multiple temperature reading and relay switching project with an ok web status page. I've recently been working on a greenhouse controller for a friend and figured I may as well learn node.js and write a generalized controller. The latest rendition is now fully customizable for any inputs and outputs. The code is pretty messy right now (it'll be on github once it's cleaned up a bit), but everything works and I'm excited to share!

Firstly, any number of devices of any type can (potentially) be used. Here I'm using 2 DS18B20s and the relay expansion dock. These devices are small node.js wrappers to the command line functions.

Direct pinIO is also supported with a wrapper for gpioctl. It'll be fairly trivial to to add functionality for a humidity sensor, light sensor, or anything else - assuming conversion to digital for analog sensors.

With the devices setup, the node.js class has helper functions to return helpful data for making control decisions. Then with this inputs the controller can evaluate logic values like GreaterThan (gt), LessThan (lt), and and/or. Finally, based on these values a device can be triggered to perform an action.

With everything now customizable and editable on the fly WebKeezer is being laid to rest. But much more is now possible.

One of the features I'm most excited about is the data logging.

I used chartjs to make some nice plots and the web interface allows the user to look at any log file.

Stay tuned for the code if you're into that sort of thing.

I think this is simply a wiring issue - I've had it come up before. The number should be 28.<something>. The 00.400.. is what I think is called a ghost ID - a temporary one that doesn't actually reference anything and gets replaced once communications are established.

I've made some wiring improvements and added plots. I've also gone back and forth on having the python script continuously run and waiting with sleep() statements vs exit and run again via cron. I've settled on cron and have written more data to file.

@Andy-Burgess

I have been trying to get a drop down on the web page to set the setpoint temperature (update keezerparams.txt) but have not had any luck.

you'd need some server-side functionality (e.g. with PHP) for interacting via a webpage. For me, I rarely need to change the temperature setpoint so I haven't bothered.
An onion console app on the cloud would be nice, but I haven't learned how to do that yet. Maybe Blynk?

@George-Wenzel Wow, what a post! You've confirmed much of what I had a hunch would be true about PID and have some great words of caution about compressors.

I forgot to include in my write up that I have the sensor in a jar with about a cup of water to keep the temperature stable as far as the thermostat routine is concerned. I also have the deltaT set to 0.9C. (The freezer turns on once ~100 minutes.) But protecting the compressor is key and I should include a failsafe measure to prevent frequent cycling in in case of who-knows-what.

I was able to import smptlib on my desktop python installation and send emails, but not from the python-light installation on the omega. It seemed like there were too many extra required libraries. I got around this by using

mailsend -to your_name@gmail.com -from your_name@gmail.com -ssl -port 465 -auth-login -smtp smtp.gmail.com -sub "Subject Line" +cc +bc -v -user your_name@gmail.com -pass securePassword -attach /path/to/message/body.txt,text/plain,i

from a system() command.
mailsend is in the opkg repository.

Thanks for the feedback. I do have a temperature differential setting (not too well documented, I guess) that's the same idea as a timeout, right?

# make relay decision based on tempC
if tempC > (setpoint+deltaT):
        if relayState == 0:
                setRelayOn()
                print "turning relay on"
                relayState = 1
elif tempC < setpoint:
        if relayState == 1:
                setRelayOff()
                print "turning relay off"
                relayState = 0

This keeps the freezer cycling once every ~100 minutes for about 12 minutes. (Plots coming soon!)

I've looked at using a PID library for another project (RIMS). I found it a bit hard to get the constants set properly so I ended up using a duty cycle setting for PWM control with that project.

I've finally got my project off my desk and installed on my freezer. Keezer actually, a chest freezer for kegs.
http://martinbuilds.blogspot.com/2017/02/the-webkeezer-omega2-powered.html
It measures temperature and switches a relay to keep the freezer at beer temperature. As a bonus, it tracks a second temperature to show how even temperature is throughout, and it has a simple float switch to alert if beer is leaking onto the floor. (I've had two too many leaks happen in the last several years.)
All this can be displayed while on a local network. No cloud integration yet.