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#publiclab, 2013-10-05

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All times shown according to UTC.

Time Nick Message
15:08 meeting Meeting started Sat Oct  5 15:08:28 2013 UTC. The chair is btbonval. Information about MeetBot at http://wiki.debian.org/MeetBot.
15:08 Useful Commands: #action #agreed #help #info #idea #link #topic #endmeeting
15:08 btbonval #topic water monitoring
15:10 #info notes start after meeting started properly
15:15 #info Jack (on net meeting) is working on syringe pump to sample water
15:25 btbonval has quit IRC
15:34 btbonval <btbonval!~bryan@wsip-98-172-46-73.no.no.cox.net> has joined #publiclab
15:35 btbonval #info Jack uses Solaris Launchpad is a microcontroller for $8
15:35 #info Wylie asks about shipping reference standards, concerns about lead. Jack adds arsenic and cyanide as additional examples of hazardous materials. Shippers won't be happy, it will be more expensive, but it should be doable.
15:35 #info Jack says that standards are hazardous materials and they simply have to be handled and disposed off using the appropriate protocol of the local  institution being worked with or the originating university of the researcher.
15:35 #info clarification: Wylie was originally asking about diverse protocols for handling the hazardous standards, and the answer from Jack was that protocols change: no standard protocol for standards. Consult with the local science authorities
15:35 #info A question was asked something along the lines of if there any suggested sample sizes for different bodies of water. Jack responds that the sampling location is extremely important, need to be over the sewage disposal or chemical disposal on a boat.
15:35 #info Willy (original asker) asks for clarification about how many samples (from say the Mississippi River) are adequate to say something valid about the waterway
15:35 #info Leif responds that several samples from tributaries of the main waterway will be telling of the main water source. If the target is found in tributaries, then work up the fork network until the point source of pollution is located.
15:35 #info Jack adds that the pollutant target being sought will have increasing concentration past each fork as one gets closer to the source. Sediments will concentrate target materials near the point source.
15:35 #info Dan asks how to handle sediments
15:36 #info (Clarify Person A) looking for Iron Redox in sediments of LA rivers. The data was noisy and the source of noise could not be determined. The soil sampling in the field ended up being unusable regardless of the protocols recommended by labs.
15:36 # Wylie suggested looking into methylation or uptake by plants nearby for stronger sampling certain compounds
15:36 #info Wylie suggested looking into methylation or uptake by plants nearby for stronger sampling certain compounds
15:36 #info Jack says one way to get Iron into solution from sediment is to digest with Nitric acid. That work will involve non-electrochemical detection: atomic emission/absorption. Mostly wet lab techniques due to handling of nitric acids
15:36 #info Jack ends remote connection
15:36 #idea Matt is going to start a potentiostat mailing list.
15:36 #info Catherine asks will Jack's simple kit be distributed through Public Lab? Leif thinks maybe.
15:36 #info Leif chases sewage overflow and is like tots pro at it.
15:38 #info Leif recommends real time data feeds (e.g. GPRS) of water sampling sensors because data logging is prone to loss due to sensor being compromised (water breaches into electric components or washes away)
15:39 #info Leif publishes data to Xively (internet of things platform formerly called Cosm formerly called Pachube)
15:40 #info Leif prefers serial output sensors because it maximizes the devices that can interface it easily (Arduino,  Raspberry Pi, serial/USB on computers, so on)
15:41 #info Leif uses Vernier linear sensors for being cheap and easy to use. nonlinear sensors have neat configuration parameters, which is apparently super duper exciting.
15:42 #info Matt says many sensors don't usually offer ways to hook up to anything but the proprietary software/hardware interfaces, and when asked, will push back.
15:42 #info Leif and Matt like Vernier because the sensors don't require the proprietary interfaces
15:44 #info conductivity probes need to purchased considering where they will be placed (eg salt water vs fresh water) because the probes usually have limited ranges.
15:44 #info Matt asks what sort of DIY stuff is all this cheap and easy to use stuff good for?
15:45 #info Don interjects that teachers are already building curricula around Vernier sensors
15:46 #info (Leif reminds a problem raised by Jack) the conductivity sensors cause electrolysis of water which leads to metal deposition plating on the probes, which limits their lifetime. gold tipped probes don't plate out as fast
15:47 #info Leif is using a platinum tipped probe which can last something like six months of use due to the inactivity of platinum
15:49 #info Leif: water conductivity changes based on salinity, total dissolved solids, all kinds of salts, pollution which all conflate the conductivity calculation. It's one of 4-5 measures for water quality.
15:49 #info Catherine asks about the other measures. Bacteria, Dissolved Oxygen, pH, redox potential.
15:49 #info clarification: answer from Leif
15:50 #info pH and redox help understand about metals and solids in the water, conductivity is already noted, dissolved oxygen and bacteria help understand biological influences in the water. Taken together they can tease out conflation between measurements better than any measure taken alone
15:51 #info Matt talks about cheapstat which requires advanced soldering and electronics, but its extremely inexpensive and there is a peer reviewed paper with arsenic detection in solids using it
15:53 #info Matt, at a space in Portland, will be discussing techniques for hacking SMD  (surface mount, tiny tiny) electronics since it isn't the easiest of electronics to work with by hand
15:55 #info Leif says that redox on probes is a probable source of failure
15:56 #idea Leif will present the specifics of his particular probe and make plans for dropping it in water as a Barnraising activity
15:56 #endmeeting
15:56 meeting Meeting ended Sat Oct  5 15:56:31 2013 UTC. Information about MeetBot at http://wiki.debian.org/MeetBot. (v 0.1.4)
15:56 Minutes: http://meeting.sugarlabs.org/p[…]-05T15:08:28.html
15:56 Log:     http://meeting.sugarlabs.org/p[…]13-10-05T15:08:28
19:33 Meeting started Sat Oct  5 19:33:47 2013 UTC. The chair is btbonval. Information about MeetBot at http://wiki.debian.org/MeetBot.
19:33 Useful Commands: #action #agreed #help #info #idea #link #topic #endmeeting
19:34 btbonval #topic IR camera magicianry
19:37 #info Don: cameras capture red, green, and blue. NDVI = (red channel - blue channel) / (red channel + blue channel); red will represent infrared, blue will represent sort of absorption by the plant
19:39 #info Camera will absorb infrared into the red channel, but camera manufacturers add infrared filters to block out the IR. Remove the filter and red channel will measure some level of IR
19:39 #info Used to measure plant health based on plant's absorption due to photosynthesis (blue channel) compared to reflection of infrared (red channel)
19:41 #info Farmers use NDVI to measure the health of their crops, some projects are working to identify plant species from NDVI.
19:42 #info NDVI is done from the air using airplanes, kites, balloons, to map the plant vegetation and health en masse
19:43 #info Matt: history of PL with IRcams: Jeff did some conversions of cameras to see IR in 2010, Scott wanted to use technology to identify wetlands plant/water boundaries and coastlines.
19:48 #idea how to use IRcams for small scale imagery for e.g. gardens in NYC?
19:49 #info Matt, farmers tend to be expects at small scale, picking up leaves and squeezing stems to judge health so that NDVI doesn't add value
19:50 #idea Ted: what about NDVI for algal blooms?
19:50 #info general agreement that it'd be neat
19:52 #info Don: western mass has a problem with water chestnuts as an invasive species. Don and co went out on canoes and balloons to map the chestnuts; identification worked well in the near IR
19:53 #info Infragram sandbox to process near IR camera pictures, process NDVI, and show them side by side with the IR and blue channels.
19:55 #info code for Infragram sandbox is on github. https://github.com/Pioneer-Val[…]e/infrapix-flask/
19:57 #info Ben Gamari submitted javascript code to process images on the front end
20:00 #info Jeff generalized the hard coded NDVI equation of (IR - B) / (IR +  B) into a mathematical language dubbed Infragrammar that supports channel mixing with arbitrary math supported by Javascript
20:01 #info to make NDVI by hand, type this into Monochrome: (R-B)/(R+B)
20:03 #info supports arbitrary variables in formulas which has a slider to interactively experiment with image output
20:03 #info Hagit asks how to interpret NDVI or any false color images if not using RGB (normal human perception)
20:04 #info Don explains that with a particular NDVI example, colors in the blue range indicate less to no photosynthesis while colors in the yellow and red indicate higher photosynthesis, which indicates thriving vegetation
20:06 #info How can quantitative measurements that determine plant health by correlated to NDVI?
20:07 #idea Ted: perhaps perform experiments on plants with treating plants poorly to get some quantitative idea about plant health measures in a controlled environment and see how NDVI correlates
20:08 #info Cindy: NDVI can be quite different depending on where the sun is in the sky and other ambient lighting conditions such as clouds
20:09 #info Matt: how quantitatively accurate the Infragrams are is a lesser priority to maintaining consistency across all the various hardware and software platforms, given that many infragrameters are DIY
20:09 #info Ted and Cindy have found that two or three cameras flown at the same time can show different NDVI results, as an example of the lack of consistency that should be worked on
20:11 #info Ted suggested having some kind of control color like Mars rovers use in a palette
20:11 #info Bryan discussed grey cards as an example of what photographers do to calibrate light levels
20:12 #info Matt showed a sort of multicolor tile with photographer grey, blue, green, white, black, and a color that should appear black in visual but white in IR
20:14 #info Bryan doesn't think the card would work in flight because it won't capture ambient light of the subject, Matt noted the focal length problem (focus on the card or the ground?).
20:14 #info Bryan suggested that Matt's card would be very helpful for working on small scale experiments and determining consistency between cameras for calibration purposes
20:16 #info Dan would like to use CHDK to lock down camera settings to increase the consistency of shooting many pictures across cameras or across cameras.
20:17 #info Matt finds that NDVI is a quantitative tool that yields qualitative results, which might lead it to say weak generalizations especially in small scale
20:18 #info Dan: what do the big agricultural folks do? what's their capability?
20:18 #info Matt: find locations where there are inconsistencies in an image, then send someone out for closer inspection with other tools
20:19 #info Cindy: farmers in the UK pay a lot of money for satellite imagery of all kinds.
20:21 #info Ned Horning had found object and texture recognition algorithms, but they are difficult for beginners. Don suggests taking them and putting them into the Infragram sandbox would make these analyses much easier and more accessible for the general public
20:26 #info some discussion about insects and other forms of visual perception outside human range
20:26 #info some discussion about IR light sources for night lighting and controlled sources
20:27 #info switching to out of scope spectral workbench discussion and images
20:31 #info The old film negative filter blocked visible light but allowed IR. Two cameras would be needed, one to capture IR and another to capture VIS. The new infrablue film allows blue and IR through while blocking the other wavelengths
20:32 #info switching to physical modification of cameras
20:32 #endmeeting
20:32 meeting Meeting ended Sat Oct  5 20:32:23 2013 UTC. Information about MeetBot at http://wiki.debian.org/MeetBot. (v 0.1.4)
20:32 Minutes: http://meeting.sugarlabs.org/p[…]-05T19:33:47.html
20:32 Log:     http://meeting.sugarlabs.org/p[…]13-10-05T19:33:47

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