Derek Callihan

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since May 26, 2017
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Recent posts by Derek Callihan

Jennifer Richardson wrote:I have been talking to Paul, and he is willing to spend a bit more if we make this a milestone stretch goal (maybe $150,000).

I'm thinking something like this:

A tracking thermometer in each of the well casings (4 total).
One at the bottom of the trench.
One midway up the trench.
One at ground level.
One at roof level on the back (mass) wall.
One at roof level in the middle of the greenhouse.
One probe-style thermometer buried in the mass.
(So about $500 worth of equipment at about $50/thermometer)
Once every two weeks, someone gets paid $100 to record and post the data, plus do some microscopy to compare the water coming in to the water going out and report the results. ($1,200 total, $100 per session, 2 sessions per month for 6 months, and then a $1,000 bonus for completing the test = $2,200).

We already have a microscope, but if we could figure out what kind of camera attachment thingamabob it needs and buy one of those (unknown cost), that would up the coolness factor of the data collection a lot, since we could post pics/video of the microscopy.

So $2,700 + whatever a microscope camera attachment costs -- say $3,000 total cost for the whole stretch goal.


My thoughts: Is the instrumentation no longer wrapped into the $100,000 stretch goal? $150,000 would be beyond even the most optimistic projections based on the data from the previous kickstarters and it seems a shame to place something that would add so much more information and value for almost nothing (1.5%-3% of the total raised) behind a stretch goal that is unlikely to be met.

Has there been discussion of the power supply and internet issues and have those been built into the calculations of the stretch goals? For this thread, we were assuming that a power supply in the form of solar panels and a battery bank would be available to power the instrumentation. Has there been any discussion towards providing internet connectivity at the lab and/or greenhouse?

Looking at the setup Charli put together in his thread, it looks like you could have the instrumentation and recording devices assembled for around $300. I personally would add include humidity and light sensors to provide solid answers to the people questioning the effects those things will have in the winter. If you wanted to add a bit more of the "WOW" factor, include a camera, or three, to take photos at set interval, such a every 4 hours during the daylight hours. Putting an analogue thermometer and hygrometer in the shot will along you to cross-reference your instrumentation readings as well as being able to have a visual record of everything that occurs. As a bonus, it makes it super easy to make cool time lapse videos showing the progress.

Based on some very quick math, I believe that would run about $500. That leaves $2500 of the proposed $3000. From my post above, it appears you could have internet connectivity at the lab/greenhouse for 3 years for that price. This would make logging and uploading the data much simpler, as it could be automated, and eliminate the need for someone to manually handle the data logs, which makes up a large majority of the cost currently. Not to mention opening to door for the many additional opportunities that would be available with an internet connection there.

On the microscopic analysis of the water, I think that should be a separate stretch goal, as it seems independent to the instrumentation. I would also question the usefulness of the information you would obtain from doing it. If someone is more knowledgeable, please correct me if I'm wrong, but I believe all you would be able to see it that the water coming is has more particulates than the water going out, which can be observed visually. To have an accurate measurement of how much cleaner the water is at the end, you would need a turbidimeter, which is a bit of a sensitive and pricey instrument.
3 years ago

Charli Wilson wrote:I am in the UK, so any links to products will be ones I can get hold of. I've tried to not be too specific- everything will also be available elsewhere in the EU/US. A lot of parts can be ordered most cheaply from China if you can wait for the shipping.

You will need:
A pi, I used a pi zero W but any pi will do, old pi a/B and pi zeroes use the least energy- if you're thinking of taking this project off grid.
A micro sd card to fit in said pi, I recommended 16GB or more. No need for anything massive though.
A one wire interface of some kind, I use the sheepwalk electronics ones:
The RPI2 v2 for the pi zero, or the RPI3 v2 for larger pi- this provides more transport buses and is suitable for more sensors, or sensors going off in vastly different directions.
DS18B20 temp sensors- either the TO92 ones, or the waterproof version if you need them to be waterproof, some ebay links as examples: or
Cat 5 or cat 6 cable, and a kit to fit your own rj45 ends to these is handy as well- you’ll need the rj45s themselves, i recommend the ones with a loading bar, or pass-through connectors- for ease of getting the wires fitted, like these: You’ll also want an rj45 crimping tool.
RJ45 3 way connectors- buy more than you need as they’re all really jippy. The black plastic moulded ones are better than the cream plastic ones, like these: . Or you could go for the sheepwalk electronics 4 way connectors, these are ace- RPI3a port splitter,

You will need a few things to develop on the pi. If you have a separate PC/laptop and wifi then all you’ll need is a microsd card reader. You will also need a monitor and keyboard with the relevant adapters to connect to the pi.


For a point of reference, what would be your estimate to build the complete setup you've described, setup the programming necessary so that all that would be required is to hook everything together and turn it on, and ship it to the lab? (Assuming you were inclined to do so.)

And if you could, the additional cost of adding half a dozen humidity senors, half a dozen light sensors, or three cameras that can triangulate the space and taken a photo at a given interval (such as every 4 hours during the daylight hours)? And perhaps a price point to include all three options?
3 years ago

paul wheaton wrote:Maybe we will never reach this, so it might have been a waste of time to set this up, but we have now made arrangements for two more stretch goals:

$70,000: The High Art and Sublt Scienc of Scrounging by James Juczak

$75,000: Sepp Holzer's 3-in-1 Permaculture documentaries (Farming, Terraces, and Aquaculture)

Looking at the Kicktraq charts linked above, it looks like it's following, more-or-less, the same long "U" pattern as the previous book kickstarter. There's a higher initial surge for this kickstarter and a steeper trailing off, but it's within a few thousand dollars and 100 backers as the book was at the same point in the timeline. If anything, the average pledge is lower, which means the potential for people to increase to a higher package toward the end is greater, especially if we start clearing a few more of $100 and up stretch goals.

Granted, it's only based on a sample size of one, but if it follows approximately the same pattern, $100,000 should be well within reach.

Edit: Because apparently I don't have anything better to do on my lunch break, I went back and looked at the data from the kickstarters going back to the Rocket Mass Heater kickstarter. In short, the trend holds across the past 5 kickstarters. I'm probably not telling Paul and Co. anything they don't already know, but I thought other people might find it interesting.

As the limited times goodies have been offered in the first few days during the more recent kickstarters, the spike at the beginning has become more pronounced, as has the spike in the last 3 to 5 days of the kickstarter. Presumably because once more goodies are unlocked at the higher tiers levels through stretch goals, a portion of people who already backed bump up to that tier to get them, which supplements the large amount of people who watch a project but don't back until close the end.

Generally speaking, the trend is the last five days are approximately double what the first five days are. Assuming it holds true this time, I'd estimate we finish somewhere in the $120,000 to $130,000 range.
3 years ago
Seeing as how it looks like the electrical issue has been tackled, I'll give a go at attacking the internet connection issue. It looks like AT&T isn't nearly as generous with their offerings as some other companies, but it does have some. Looking at them, rather than getting a phone, a wireless hot spot would give you more flexibility at a lower cost. The two viable options would be either the Global Modem USB800 for $180, which is a USB device, so it's limited to one device, or the Nighthawk LTE Mobile Hotspot Router for $250, which is a wireless router connected to a wireless hotspot, so you can connect multiple devices. Both of these would require a data plan from AT&T, which only offers two plans for them: $50 for 10 GB a month or $70 for 15GB a month. 10 GB a month is probably overkill for just uploading data, but that's your lowest option. Looking at the reviews, it seems like the biggest potential problem, assuming you have a strong enough signal, is the rather limited range of the wifi.

Just my opinion, but setting up a dedicated hot spot at the lab (assuming the greenhouse will be in close proximity) seems like it would be adding a lot more options to future endeavors. As long as there is power at both locations, adding a pair of network extenders ($30 each) should be pretty straightforward. A little back of the envelop math and it looks like you could cover about three acres with that set up. Adding up the costs, assuming the router, a pair of network extenders, and the lowest data plan for three years, plus a bit of fluff because there's always the unexpected costs, it looks like you could have internet there around $2500.

On the instrumentation side, it sounds like Charli is the man with the experience and knowledge. It looks like the Pi is the way to go, being able to collect and log all of the different inputs from the variety of sensors and wirelessly transmit them out. I'm assuming it would be fairly straightforward to setup a database that automatically extracts the data, organizes it, and generates some pretty graphs to look at. Having that database linked to a webpage accessible for backers (or anyone) to look at in more-or-less real time would be an added benefit that seems like it would take minimal effort to maintain once it's set up.
3 years ago

Jennifer Richardson wrote:The main barrier to us doing this kind of data collection is equipment availability and compatibility with our constraints. We have no wifi on the Lab, so anything that requires wifi is out; many/most weather stations that we are interested in have required a wifi gateway. We need the data collection to be somewhat automated (not something you have to go plus a USB drive into to get the data) and the data to be conveniently shareable, preferably with visualizations, in order for it to do much good. A bunch of text posts in a thread with me manually transcribing temperatures from a screen readout once a week is not going to be of much value. And we need the equipment to function to at least 20 below zero F for the outdoor stuff--which most tracking thermometers don't--and/or to be waterproof and tolerant of humidity depending on location. This kickstarter might open up new doors in terms of equipment, since it could expand our budget significantly compared to when I was looking for tracking thermometers for the Abbey last summer, but so far I haven't been having much luck. I am open to suggestions, however.

I haven't had a chance to watch the Youtube video from Friday yet, so apologies if some of this has already been covered. I think to get a good handle on the starting point for instrumentation, we'd need to know the constraints we're working with. You say there's no wifi at the location. Does that mean there is currently no hardwire connection and/or there is no practical way to get a connection there? Is there any cell reception at the location?

Is there any electrical connection there and/or is it practical way to run electricity there (purely for instrumentation). Or will everything need to be run on batteries? If batteries, could there be a possibility of a small solar array and battery station to split the difference and allow the instrumentation to be wired?
3 years ago

lesley verbrugge wrote:Does anyone have any thoughts about combining a root cellar into the design. Somehow. Space is at a premium for us, and we'd like to combine the two if it's possible. Any of those clever engineering types out there with thoughts on this?


The bottom of the tench should stay around 50 degrees.  If the humidity is kept low and sides of the trench are properly reinforced (and that's a big if), in theory, that could make a pretty good root cellar. Add an access hatch and a ladder down, perhaps a set of selves set low along the walls, and voila!

Standard disclaimer as I have no idea how practical would actually be, just throwing out the possibility. Though I would love to see the bottom of the trench instrumented to see if this does turn out to be the case. I feel like moisture is going to be your biggest issue with this method. It could be a very useful case of function stacking, if it works out however.
3 years ago
Out of curiosity, what is the plan to ensure the greenhouse doesn't overheat in the summer months? I know most of the focus is keeping it above freezing (or better) in the winter, but there's still summer to contend with. I'm assuming passive wax or oil cylinders on a vent opening would be used since they are a pretty proven zero-energy solution, but I didn't see any mention about it, one way or the other.  
3 years ago
I haven't had a chance to listen to the podcast, so if this is already in the works, average minds sometimes have the same thoughts as great minds? Throwing an idea out for a stretch goal: Built-in instrumentation at multiple levels. Thermometers at each level (Roof, Beds, Trench, Bottom of Pipe (if you can manage it)), humidity gauges, light meters at multiple locations, etc., all tied into an automatic logging software that monitors things 24/7.

Combine this with things such as having multiple well casings and destratification pipes that you can open or close and you'd be able to get good, hard data on if and how much of an effect each has, ideally looking to find the point of diminishing returns for each, and how they interact with one another. Additionally, this experimentation could be extended to things such at the color of the back wall. Start with unfinished wood and get your baseline measurements. Then try painting it a bright, reflective white. Then maybe try a reflective metal foil cover. With the instrumentation in place, it makes quantifying any differences from these changes much easier to illustrate and allow you to more quickly spot any potential problems.
3 years ago
Just a quick follow-up, if anyone is referencing this in the future. The growth from last year was dead, but I did get new growth from the roots, after the weather warmed up more. I cut the dead growth back close to the ground and it seems to be doing pretty well this year so far. It's about three foot tall and starting to get more bushy at the moment.

I'll be cutting it back to the ground and covering it once we've had a hard frost, but seeing as it came back this year with only minimal protection from last year's pretty cold winter, I feel more confident that it will be able to make it going forward.
5 years ago
I refreshed it at 15 seconds and saw we were 60 short and couldn't stand the thought of coming so close and falling short, so I bumped mine up to cover the difference.

This is why I don't gamble, I get too emotionally invested. At least it's going to a worthwhile cause and we all get the benefits versus whatever I would have wasted it on instead.
5 years ago