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p-v-o-s / pioneer-valley-open-science.github.com

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Sanitation #17

Open dwblair opened 11 years ago

dwblair commented 11 years ago

Image

Background

Looking into building / prototyping / researching techniques for clean, accessible sanitation; particularly methods that allow for the production of energy from e.g. bacteria.

Fastie commented 11 years ago

A biomass recycling technology upgrade is desperately needed. Please help.

dwblair commented 11 years ago

Chris -- Quick glance indicates that you need a way of monitoring temperature remotely -- just so happens, I'm putting the final touches on a $150 Arduino-based temperature probe system that can connect to Wifi,be monitored on cosm.com (am working on Google Spreadsheet support). Main use case was going to be monitoring -80 C freezers in biology departments, but this seems like another use case. Design includes an LCD and a case; your use case might be a bit different, maybe less costly. Will post updates as I get this baby finished.

dwblair commented 11 years ago

And if you don't have a WiFi signal out at the pile, this might be a nice motivation for looking into an Xbee add-on with Matt B. Fun.

Current state of the art (will look a bit less gnarly after this week, I hope):

It's designed to be placed in a relatively-waterproof container, with the ethernet cable connected to a wifi repeater.

Jeenode option instead

On the other hand -- if you want wireless temperature monitoring of the pile, and it's less than 500 feet away from your house, a Jeenode might be the best, battery-operated solution. We can rig one of those up for you with (rough guess) around $90-ish of hardware from moderndevice.com.

Fastie commented 11 years ago

That is exactly what I need. I have always thought that my compost pile should have its own web page. The garden is well within the range of my home WiFi network. The temperature sensor has to withstand rotting tissue and temperatures up to 160° F. The lead to the sensor has to be two or three feet long and also tolerant of high temperature and grossness. The controller and Zigbee/Jeenode has to be in a completely weatherproof housing. An LCD is optional.

I'm glad you are already working on this. Incidentally, I can't imagine any reason that anybody would find it advantageous to be able to remotely monitor the temperature of my compost pile. (But I bet you can't wait to see what the temperature is tomorrow morning.)

dwblair commented 11 years ago

Honestly, when I had my freezer temp monitored over the course of a few days, and could see the little ups and downs associated with people grabbing e.g. a frozen chicken packet, lingering, and returning the frozen chicken in favor of some broccoli, I felt like a was a Curiosity Rover engineer at JPL. A daily readout of compost temp will likely provide the same feeling; but might even be useful; the energy given off from a compost pile is something that has been exploited in the past to do meaningful work (heat greenhouses, etc), and this would be a step towards quantifying how effective such a system at home could be.

Will write more about the various options I know something about later. Aside: can you run an electric cable out to the pile, or bad idea?

Fastie commented 11 years ago

I have had an extension cord stretched out to the garden for several weeks to power the electric fence to keep varmints off my corn, by Golly. But I have to remove it every week to mow the lawn, so it's a pain. But a new compost pile is heating up only once or twice a year (I don't have enough organic matter to do it more often). So it would be reasonable to have power there, although battery power would make the device more useful for other things (air column temperature gradient during flight?)

The temperature graph of the compost pile is growing nicely.

Could you see the graph there before now?

dwblair commented 11 years ago

Hi Chris,

I'm posting a snapshot of the graph here, just for archival purposes. Super, duper, cool. Can't wait to dig into this problem. Even just brainstorming solutions has already been productive / motivational for me.

Off-grid power

A friend who is a local farmer wanted to chat about designing and building an off-grid motorized vent control for controlling the greenhouse temperature. The basic idea was an Arduino controlled thermostat connected to a DC motor that turns a screw which determines the distance between two ends of a hinge; but how to power it all, off-grid? Our discussion turned to how to power electric fences, off-grid. Random associated links:

So, you might be able to kill two birds (via electric fence!) with one stone: charge your electric fence and keep your temp monitor charged with the same solar-powered battery. These systems are for sale, but I'd also love to look into how to do it DIY with cheap solar panels, an old car battery, etc.

Wireless temp monitoring

There are a bunch of options for doing this, and I'm still hazy on all of them and their pluses and minuses. But here's a first pass.

If you want live data on the web from your compost pile, then you need to be sending data from your compost pile to the internet. Here are three categories of solution for this:

  1. Sensor + Transmitter --> Receiver connected to a PC, which is always kept on and connected to the internet --> internet.
  2. Sensor + Transmitter --> Receiver with ethernet shield connected to internet (e.g. inside house) --> internet
  3. Sensor + Transmitter + WiFi repeater --> WiFi router connected to internet --> internet

(1) requires having a PC on all the time, even when you're not using it for other purposes. But if you already have that, and if it's already within 500-ish feet of the compost pile, then there is a nice solution in the form of a Jeenode setup that we could try. A Jeenode + sensor will be at the pile, and the Jeenode won't require much in the way of a battery (it's set up to be low-power). The Jeenode transmits a signal via a particular radio protocol to another Jeenode inside the house, which is connected to a PC. The PC is listening for the Jeenode signal constantly, and uploads it to the web. If you have to turn off your PC or restart it, then you'd need to find a way to restart the program that listens / sends, or do it manually. So this can be a bit of a pain, but it's still doable. It has the advantage of being relatively low-power (I think).

(2) I don't yet know much re: the details of this setup, but this is an option that is pretty common, I think. It uses something like a Jeenode (or equiv) to speak to another Jeenode (or equiv) inside the house, and that Jeenode has additional hardware that allows it to connect directly to the ethernet. Folks at e.g. Safecast likely know a lot about this option, as I think they've used it before themselves. This might be the best of both worlds -- low-power sensor at the pile, but no need for a dedicated PC inside. The hardware inside the house would simply be always-on, always-transmitting (unless the power went off inside the house -- but when it comes back on, the device can just start up automatically). The radio protocol ytpically isn't the standard WiFi, it's something else.

(3) This is a solution I've been working on recently, but the main use-case was for freezer monitor inside a building that could be plugged into a power outlet. I think it could be powered via e.g. the solar power system above, and would love to look into that anyway. The advantage is that you get to set it up to just broadcast to your WiFi system inside, nothing else required. Power consumption seems to me to be the main disadvantage; but maybe there's a clever way around this.

Fastie commented 11 years ago

That's handy that you can get a solar panel and charger for $100. I could put that on top of my pickup cap and run a laptop forever.

My desktop stays on most of the time, and it's less than 300 feet from the compost pile. So any option would work. The simplest and least expensive is probably option (1), so that might be the best route.

How many sensors can a single Jeenode support? I might need to describe the 3D spread of heat throughout the pile. Or monitor the depth of soil freeze in the winter.

dwblair commented 11 years ago

Fastie commented 11 years ago

Really excellent explication. I like that option. And it's like you get four sensors for the price of one. If a JeeNode supported, like, 12 sensors, I would buy that many. Imagine the 3D visualization of heat spreading through the pile! But $35 for four more sensors is an obstacle.

It looks like this would fly on a KAP rig rather comfortably, maybe with temperature, humidity, and pressure sensors. Is there an available pressure sensor that is good enough to derive altitude? If so we could describe the air column. Just take a laptop to catch the data. With the H2S sensor, we could fly through and describe an industrial stack plume.

However: 1) Shouldn't you be hacking away at your walkie-talkies? 2) Why is this discussion under sanitation?

dwblair commented 11 years ago

(Shhh: this discussion is filed under "sanitation" because that's where our enemies will least expect to find it -- "security through obscurity".

(And: yes, will be getting back to work on the Old FART, stat ...)

Re: 12 sensors ...

I don't know how to implement it as well as I'd know how to do the Jeenodes, but: an Arduino Mega Board, for $50, could handle up to 15 sensors. You'd need to add an Xbee to it, and then another Xbee + housing on the PC side, to communicate with it. Seems like there are a few ways to skin this cat. I'll ask Matt B. what the Xbee setup would involve, and whether I've got it straight.

The 3D viz. of heat spreading would not only be super cool/geeky, but might be of scientific / tech interest too, eh? From a biological perspective, but also when trying to determine optimal timings / placings of tech for extracting heat from the pile? This is super fun. As a first pass, maybe 4 sensors, spaced equally vertically, or two on the top layer and two on the bottom, would give a nice picture of how things proceed.

Re: KAP rig:

dwblair commented 11 years ago

Draft of PLOTS Research Notes

Arduino (Jeenode) wireless communication of sensor data

a) A $23 JeeNode (select the 915 MHz or 433 MHz option)

b) A $37 [JeeLink] USB

c) A $16 AA Power Board for Jeenode to power the JeeNode where it sits in the pile

d) A $3 thermistor from Redfish Sensors X 4 (for four sensors on the single Jeenode)

e) A 3 kOhm resistor for each sensor (so, X4) -- avail. @ Radio Shack, but will find a source online. Will cost pennies.

f) We'd want a nice waterproof case for the Jeenode that also allows for the sensors to poke out. You'll probably have better ideas, but I saw that Adafruit sells a nice little Otterbox for $10; we could drill holes in that, and put little O-ring rubber gaskets in for good measure?

Total configruation -- around $100, plus shipping and tax (I think?) for four remote sensors stuck in a hot, gooey, stinking pile.

XBee wireless communication of sensor data

Compost Temp Monitoring

Microcontroller Platform Use Cases Matrix, Pros / Cons

Fastie commented 11 years ago

The above discussion about remote monitoring of compost temperature is introduced in this research note at PLOTS: http://publiclaboratory.org/notes/cfastie/9-14-2012/remote-temperature-sensing

dwblair commented 11 years ago

Getting python to read the jeenode:

Following the instructions (using python-eeml here): http://community.cosm.com/node/114

To download and install the python-eeml package: http://pypi.python.org/pypi/python-eeml/1.2.0#downloads