Aquaponics - Electronics - Digital demand fish feeder

The water temperature in my aquaponics fish tank is today sitting at around 20c This means my silver perch are back to feeding like crazy.

I suspect they would eat a lot more if I fed them 20 times a day, so I rummaged around in the darkest depths of my house, and found my demand fish feeder project.

When I made it as part of trying to learn electronics, I happened to be on lots and lots of morphine because I had a rock festering in my kidney. At least I think that's what it was for.

Geology is interesting and all, but who wants to grow rocks in your kidney.

Anyway, it seems that whatever you learn when your brain is in an opiate fog stays in that fog. At least it did for me.

Every now and again I've discovered this poor little open source project, and tried to figure out what it does, and why it doesn't do what it should do, and it always ends in my just putting it back into the darkest part of my house, and leaving it there until for some new reason I think I'll understand it again.

Yesterday I looked at it and it made sense.

Only a bit, but that's a bit more than usual, and I wasn't even on morphine.

I traced everything from the pins to whatever input or output  (switches or lights) devices were attached, and almost all of it seemed to do something. The three adjustable gizmos (pots) in the top right are not connected, but I looked at my code, and worked out what they should be connected to (they adjust food amount, total food allowed in a day, and light sensitivity to trigger the dawn reset.

There are also these four resistors that dont seem to do anything.

I'm guessing they are either, connected to the potentiometers (adjustable gizmos) or have something to do with the second circuit that I found.

The second circuit looks like this, and I'm pretty sure it was meant to be mounted like this.

It has a button and a switch.

I remember making a water proof override switch so I could give the fish a dose of food when I visited them and wanted to see them hit the demand lever and get fed.

Now the four resistors might be for the pots, but I cant remember if they needed resistors. They are, after all, resistors.

I think.

But some things need resistors so they don't feed ambient static into the chip, and give false readings that look like button presses or whatever.

Who knows, but it feels a bit like I'm almost, right on the edge of nearly being back on track.

120 things in 20 years Aquaponics - Digital demand fish feeders are sometimes better off recycled and started from scratch.

Aquaponics - Fried tomato root

When I roast onion I always cut them into quarters, and leave the root on.

Partly to hold them together, but also because when the onion root gets crunchy it tastes great.

Unless someone points to their toxicity or something, I'm going to try some other fried roots from my system.

Tomato root springs to mind immediately at it has a very pleasant aroma.

In a dirt garden, you might never see the extent of the root system when you pull up a plant.

Growing carrots in water only has got my seeing, and thinking about the root systems of plants as a potential delicacy.

I hope I don't die!

[note from the future - it turns out tomato are part of the night shade family, and are toxic, so I wont be going through with any tomato root frying]

120 things in 20 years - If its worth growing, it's worth frying. [or not]

Aquaponics - Perfectly good carrot

I tend to avoid eating things that are supposed to be orange, but that are green.

Oranges are an excellent example of why such a policy is a wise one.

But here is what 100% of reader feedback inspired me to do...

I thought I'd cut open the carrot I grew in water and see what it looked like on the inside.

It looked like a normal carrot.

So I ate it.

And I didn't die.

Now the carrot in question looks like this.

And it tasted exactly like all the other carrots I've harvested.

Sweet, and delicious.

I suspect the totally normal shaped carrot was because my nutrient levels are so low. I'm running 300 litres or growbed and a thousand litres of fish tank (plus an extra 50 litres or so in the duckweed tank, and another 50 litres of sump) The result is (in my uninformed opinion) the carrot fell back on it's normal modus operandi for growth rather than branching out (Elvis shaped) to take advantage of nutrient that may have been there if I kept more fish.

Not much nutrient = reach down low in search for more.

Lots of nutrient = branch out all over the shop and get a good price on E-Bay for currently popular diety/elvis look-alikes

I plan on writing more posts, so in the event that 120 Things in 20 years stops suddenly, it's almost certainly the deadly result of Mike Creuzer's advise on the consumption of the perfectly good carrot that I ate from my aquaponics system.

Aquaponics - Carrot algae

For some time now I've been growing a carrot by hanging it over the side of my fish tank so the carrot is in the water, but the stems and leaves are tied to the side and above the water line.

It seemed to have worked a bit.

The green is from algae, and I'm guessing just part of what happens to roots when you give them full sunlight.

The test was never intended to go as long as it did, and the original plan was to see if the carrots formed in any un-carrot like ways that made it a crazy idea to grow them in water.

It grew pretty much like a carrot.

This is a miniature variety, and it grew to the same size as it's cousins growing in the grow bed.

I suspected it would have no sense of direction because the nutrient and water were everywhere, and  it would have no need to grow down to get fed.

I wonder if anyone has grown carrots in space.

This experiment has been a fail in so far as making tasty food, (I'm not going to eat it) but a success in finding that it may well be possible to grow carrots by threading them through something that makes it dark underneath, and also that floats.

A sheet of polystyrene might be the ticket.

I've just started another experiment with a tomato plant to see if that will also grow by dangling it's feet in the fish tank.

120 Things in 20 years - Wasting food one slimy algae covered carrot at a time.

Fire - Potato cooker mould

I guess it was bound to happen sooner or later, but my methanol potato cooker has gone mouldy.

That happens to a lot of the truly great inventions.

I think.

Wasn't it Edison that said "Sometimes a perfectly good invention fails only because the potato always goes mouldy."?

I could be wrong.

I never took history.

Fire - Home made ethanol stove

In a previous attempt to make a ethanol stove I ended up using a potato instead of the bottom the coke can I was working on, and you can see a lot of the build in the post called Fire - Ethanol potato cooker. Because I've already covered most of the build in that post I wont be repeating it here, so read that potato cooker post first.

Sorry for the terrible photo. it hurts my eyes as I try to force it into focus. Hopefully that's just something about me, and it wont actually hurt anyone else.

After some more research I thought I'd try making a proper drink can burner. This time I spent a lot more time on slowly scribing the line with a blade to get the cuts nice and clean. Rather than putting on a lot of pressure, I pressed gently, and rotated the can under the blade holding the blade in my right hand and the can in the other. Eventually a few small holes appear in the line, and at this time you can either cut it with a little more pressure, or just press it out (I used a pen because I wasn't sure how sharp it would be, but it wasn't all that sharp).

The end result was a very neat, clean cut that needed only a light sanding.

Actually it didn't really need a light sanding at all, but I did it anyway.

I also employed the method of putting a blade in a book. This time I clamped it down with a G-clamp, and pressed the top (really the bottom) of the can down with one finger while I rotated the can with my free hand.

I used the blade and book to mark a line for the base.

But the second cut of the can required scissors as there was no "top" of the can to press down with one finger.

But scissors cut it very cleanly.

So here are the three finished sections.

The one on the left is the top with all the holes punched through with a drawing pin

Centre is the inner sleeve cut out of the middle section of the can. (see previous post)

And the bottom is on the right.

The bottom bit was stretched* by pushing a full, un-opened can into it a wriggling it around for a bit.

It's difficult to describe the motion, but if you jam it in the move it around like a ball and socket joint (like your shoulder) the lip of the can is eventually stretched. It's very easy to get off the can as there is a perfect seal, and the air pressure inside pushes the small section off.

Put your base on something flat.

Press in a full can.

Wang it about a bit**.


Now, with the inner sleeve roughly in place, you can slide the top and bottom parts together. As long as you make them meet as close to evenly as you can (ie not one side first) it will fit.

I made my base section the outside, but I'm not sure if there is an advantage either way.

It looks like this when it's lit.

And this when it's not.

120 Things in 20 years was  overheard to say "On the subject of fire and home made ethanol stoves,   I personally didn't have any blood fall out, but I would say that although this is a great project to do with kids,  if you like them I'd make sure there was an adult around to stitch them back up, and put the fires out".

* Thanks for the tip Jabro

** If only someone would come up with a way to rapidly display pictures one after the other to give the reader the illusion of a "moving picture".

Fire - Ethanol potato cooker

I was thinking about my Murray River epic adventure, and thought I might need a small emergency stove for when I find myself in a storm, or otherwise unable to make a fire. The difference between being miserable and content often boils down to a hot meal.

So I thought I'd make a ethanol stove. There are a few on the market, and they work by boiling the ethanol within a small chamber with holes around the top. The ethanol turns to a gas, exits at the holes, and burns like a nice gas stove. Lots of heat, light weight, and perfect for what I need.

There are quite a few examples of home made versions on the net, so after quite a bit of research, I thought I'd have a go.

I failed.

I found it impossible to squeeze two halves of a drink can that were the same diameter over each other.

Stupid physics.

So I thought I'd convert my failed project into a potato cooker.

It looked a little something like this...

I started with a can.

I poked some holes around the near top of it with a drawing pin.

I cut the top off with a box knife.

The best way to do this is to lightly score it, round and around, until you gently wear through.

I didn't do that, and I nearly cut all my fingers off one after the other in a series of ever more lucky near misadventures.


To cut the next bit, I originally set the can upright with the blade held at the correct height by placing it in page 321 of Stephen Hawking's book "God created the integers" which was exciting, because I finally found a use for it.

It didn't work as well as youtube told me it would.

Neither did the box knife without Steven Hawkings' help.

Eventually I used scissors. 

This pic is me cutting the planed base that the top was meant to firmly slide over.

I threw that bit away in the end, and used a potato instead.

I cut a strip from the can, and made a cut first half way through one end, and then half way through the other side of the other end.

Then used the opposing slots to make this inner sleeve.

I also cut a little v in it to allow the flow of fuel.

I sat the inner sleeve inside the outer, top bit with the holes in it.

I sliced a potato top and bottom to make a nice stable base, rested it over the top, and gently pressed it down onto the device until it was firmly stuck in place.

It looked like this and appeared to make a pretty good seal.

I added fuel up to the holes, and lit it.

At first the inner section burns and heats up the fuel between the sleeve and the outer section.

At this stage you just leave it alone for a few seconds until it warms up.

Quite suddenly and with a pleasant pop reminiscent of lighting a gas stove, the fuel turns to steam and the burner ignites at the holes.

Total surprise. 

The thing actually works. 

I quickly found a pot, and put one metric cup (250ml) of cold tap water on the heat.

As soon as you do this it snuffs the centre section, but because the holes are down a bit from the top, they continue on perfectly. 

I had a proper boil at around 5 minutes, and a slight simmer at just shy of four minutes.

Much better than I expected. This was a total success.

The entire project from the time I looked at the soft drink can to the time I could make a cup of tea was around an hour and a half, but most of that was attempting to make it without the potato. I think I could knock one of these up and have water boiled in 10 minutes with nothing but a drawing pin and pair of scissors.

Way cool. Thanks to everyone on the net that did stuff like this and gave me all your tips. My only contribution was the potato.

120 Things in 20 years - Ethanol stove - Potato cooker. Boiling water! Yum!

Aquaponics - Drip control

Waking up can be a difficult time even when you don't discover your aquaponics system's water trying to escape.

But this morning it was extra tricky, because my water was falling out.

Trickier still, I couldn't figure out where it was escaping from.

This isn't something normal people have to contend with when operating an aquaponics system, this is just something special people like me have to contend with.

I'm special because I don't do things that I know I should.

Normal people would design all pipes running into their system so that the water exited on a downwards pointing section.

Not me.

I like to have pipes pointing very slightly up, so that water runs back along the pipes.

That way when a drip finally forms and drops off the pipe, I can be sure it's left the confines of my system and falls unsafely onto the concrete.

It's very easily solved, and the solution is one I've recommended to other people, just not one I actually put into practice for myself.

By far the most simple cure is to not have pipes sloping up (or even flat) at the point the water comes out, but if that's not possible for some reason, all you need is a place for a drip to form, and it stops being a problem.

I used some cable ties to create the desired result.

Now when the water runs back it drips off at the cable tie, and the drip falls back into the water.

I knew at the time I put the pipes into position that I needed to make them face down, because I've seen (and personally suffered from) the problem before.

I have no idea why I didn't just add cable ties before. I didn't even have to think of it myself. I think a solution like this even has a name. ie its a product you can buy, or something people setting up stock troughs take in to account.

Oh well.

One day I'll make stuff that works properly, but I have to design a boat to live on for my attempt at an epic river journey, so I have no time for designing, and building stuff that works, or is actually reliable.

120 Things in 20 years - This Aquaponics drip control post puts me in a position where I can safely bet that my dear old mum buys me a better life jacket for my birthday.

Aquaponics - Can do siphon

My strawberries started to die off.

I don't like it when that happens.

I have it on very good authority that strawberries wouldn't like being in a constant flood.

It turns out good authority is good.

They went brown, then wilty, then mouldy.

They're still alive, so I thought I might just add a bell siphon, and give them the intermittent dry feet they reputably enjoy so much.

I didn't really have anything to make a proper siphon out of, so I stuck a plastic cup over the existing standpipe, and it seems to be working perfectly.

I don't understand what it is about the humble bell siphon, but once you've made a few, they just always seem to work. I'm guessing that comes down to subconsciously picking the correct size tubing or something , although I have no idea what I'm doing.

I guess that's why they call it subconscious.

It might also be that I'm kidding myself as to my tube divining skills, and that really I've just been lucky.

Anyway, I thought I might do a bit of research and actually make some kind of chart with different flow rates and the required/suitable tubing diametres etc, I remember wondering where to start when I made my first bell siphon, and no matter how much stuff I read, I could never find the kind of info I needed.


For the time being, here is my plastic cup.

I'll let you know when it fails.

120 Things in 20 years finds me asking myself, "Am I wrong to expect someone to have made a chart showing suitable tubing for a siphon build to suit a pump with a home made wire front bearing?".

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