Aquaponics - Hover fly

Since I was a kid, I always loved these little critters. I think they are called hover flies.

If I've identified these guys correctly, they are the perfect package.

From what I have read, they are attracted to honeydew, (a sticky substance excreted by aphids of which I have plenty) they lay eggs on the leaves with honeydew on them, and the eggs hatch into aphid eating monsters. It seems they eat up to 400 aphids before having a little nap and waking up as an egg laying, hovering, pollen eater.

This probably explains why I don't seem to have a problem with pollination any more.

I also don't seem to have a problem with aphids any more.

The larvae eat aphids, the adults are pollinators, and they hover perfectly.

I cant think of a better bug.

Electronics - My first repair

I have one of those digital TV recorders.

 Or at least I did.

It's always been a bit flaky with the occasional flicker of the images and a dunk dunk dunk to the sound every now and again. A few weeks ago it broke down completely. I thought I'd put my brand spanking new electronics knowledge to the test, and have a go at fixing it.

I opened the hood, and had a look for any signs of obvious damage. Mainly to me that meant looking for any components that had released their internal magic black smoke out into the world with some sign of burn marks, or melted plastic. I also looked for dust and dirt and anything else that looked out of place.

I was pleasantly surprised and a little excited to find this.

That black goo at the bottom of the large capacitor, was exactly the kind of thing I was looking for.

I did some research.

It turns out that that black goo was probably just something to do with the soldering, but what I did discover is that it's most often than not capacitors that let the team down when it comes to computers and things not working.

They way they let go, is like this.

See that slight swelling at the top. The "X" cut into the top of the component is because they tend to go pop, and the cuts release the pressure when they do.

Or at least that's what I read.

Either way, this cap is bursting at the seams, and all the others were flat.

This meant it was definitely in trouble and almost certainly the culprit.

All that was required was to but a $5 part and replace the bursting one and I should be in business.

If this works, I've just repaired a $300 item for $5 and should therefore be able to bill my household $120 for the repair, and pay back the hypothetical loan that 120 things in 20 years had to make to get started with the aquaponics, with my hypothetical earnings.

Actually I think that loan has been paid back already in salads and strawberries, but it's always good to provide Mrs 120 things in 20 years with some black numbers in the account book. Too many red numbers make my empire building long term hobby look like it might not only use all he buckets and space in the shed, make mess, and create danger zones all over the yard, but it might also be bankrupt.

Bankrupt hobby empires are never a good look.

Actually not a bad job if you ask me.

So, after soldering the new part in place and trimming the component pins, my 20 second repair was ready for a test.

Drumroll please..........

Exciting isn't it.............




Aquaponics - Dipel works

If I hadn't replaced my first sentence with this, my second one would have made a lot more sense.

Actually it doesn't seem to have a smell to love, in the morning or at any other time.

But I didn't, so there you go. I hate censorship, even when I do it to myself.

Dipel turns out to work really well, and doesn't seem to have a smell or be toxic in any way. It's certified organic, and makes caterpillars dead.

In short, I love the stuff.

Dipel is a bacteria that makes caterpillars get a little ill and go off their food.

Sorry Vegetarians.

Do vegetarians kill caterpillars, but just not eat them? I'll have to ask my veggie friends. I'll get back to you on that one.

At first I didn't mind it when I was losing leaves to caterpillars, but when they started eating fruit on my tomato vines, I had to draw a line in the sand. Or in my case I had to draw a line in the scoria.

I actually like it when I see pests in the garden, because as long as they are not in plague, they keep the predators around and well fed. If the predators are not around when a plague brakes out, there is too much of a lag between the time of the pest and the predators breeding up enough to restore balance. As long as pest and predator are both in place, we see everyone getting along just fine. (providing you consider being attacked and eaten getting along just fine). I suspect things that eat grass always breed more readily than things that eat meat. Probably because you need to invest so much energy raising a hunter with the big brains and tactical minds and all, but grass eaters can get away with brains that spend more time thinking grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass grass.

Whilst some humans spend time pondering their relationship with grass, many others spend their allotted hours on things like war, driving really fast, and baking.

At first I thought the Dipel wasn't working because I didn't see any sleepy caterpillars lying about on my scoria. Later I found ants quickly whisking them away and then not spending their ant days waiting under the caterpillar tree in the hope for more. For some reason they just left one or two ants waiting and everyone else went home to watch TV or something. But after watching them for way too long I would see them come running out whenever I knocked off one of my dead caterpillars from the tomato vine.

120 things in 20 years - It's kind of, like, you know, about everything really.

Aquaponics - Topup water

Water water everywhere etc...

My aquaponics system needs topup water every few days because the plants use quite a bit, and there is some loss to evaporation.

I would guess I'm adding around three or four litres of water per day on average. That's around a gallon for people in Gallonland.

I'm not really sure how far that amount of water would go in a dirt garden, but on a hot windy day, I'd say you would need that on my two tomato plants alone. Actually, if I was growing my two tomatoes in dirt, as a potplant, I think I'd need twice that much per day.

Much of my water saving might be about the grow house, but because I've never grown in dirt in a growhouse, I cant really offer much of an opinion.

It's often said that an aquaponics system uses around 10% of what you might expect to use in a dirt garden producing the same amount of food.

To combat the deadly toxic effect on fish brought about by the chlorine in my water supply, the water needs to sit for a day or so before being added to the fishy's world.

I choose to be a bit more lazy than that and add it to a large container every few days.

The cover has a small hole to allow water in but generally keep out falling leaves and flowers.

Lately I've been collecting a lot of flowers from a tree in my backyard, and I've also been losing fish. Since the cover went on I haven't had any more deaths, and the fish that were sick are getting better. It's probably just coincidence, but I'm not about to test it by taking off the cover, or adding flowers, so I'll never know.

I guess that's how superstition starts.

I don't leave my water to sit before adding it because I'm lazy and instead, force a delay and dilution on it before the fish get to see too much of it.

I create the delay and dilution by having move from the first container to the second via this thin plastic pipe that I have restricted by tying a loose knot in it. As a result of the knot, it drips at a reasonably steady pace.

You can just see a little clearing of the duckweed near the loop on the left. That clearing is caused by the drips falling at a rate or around a drop every few seconds.

I don't know how much water there is in a drop coming from a knot, so I figure there's not a lot of cause to measure the length of time between them.

From there it flows in and out through a siphon connecting my duckweed tank to the fishtank. The connection between these two tanks means that the depth of one is reflected in the depth of the other. Their depths rise and fall as the grow bed is filled and emptied, but not by as much as the fishtank would rise and fall if it were supplying all the water to the grow bed by itself.

The added water keeps the depth of the fishtank closer to full, and also adds thermal mass to the system just because there is extra water in the growhouse.

This chain from tap to fishtank has grown longer and longer over the months, but the flow does get to the tank in the end.

A further increase in thermal mass will be gained by my adding the big orange container to the inside of my growhouse. It will take up a lot of space, but I can use it to rest the NFT tubes on, and give them a new sense of security. Their current bucket legs are showing signs of getting soft on the hotter days, and I get the feeling I'm only a few days away from a disaster. If the buckets fail, the pipes fall, and the pump just keeps emptying the fishtank into them in a futile attempt to fill the world.

So the plan is, move the orange tank inside and make it the new legs of the NFT pipes. This will involve two people getting into the little growhouse and holding up the NFT pipes, while a third and forth clear out the old legs, and drag in the heavy container of water. That's way too many people in such a small space, and will no doubt end in at least a moderate disaster, but it has to be done.

A lot of my nightmares end in dry fish.

120 things in 20 years is a lot of things. I'm half way through my second year and I'm still sorting out my aquaponic's topup water.

Electronics - Computer meltsdown

I've put together a lot of computers from scrap over the years.

Once I had a 4Mhz machine (slow - electric toothbrush kind of slow) that had no hard drive, and another one that had no power supply. I didn't know anything about computers, but I found I could plug some wires from on to the other, and create a computer twice as large as any other, but only about a quarter as good.

Since then I've discovered that all the bits inside your computer just un-screw, and are interchangeable.

But no matter what combination of things I try, all bits of all my old computers are dead, except the BIOS, and the screen of the laptop. (the BIOS is a chip holding a basic set of instructions on how to talk to all the other stuff that's plugged in (Basic Input Output System (I think)).

So the short story is, I'm stumped.

How do three computers all die in the same week and also have all their different components be dead?

I'm starting to wish I was into UFO conspiracies.

At least then I might have some kind of explanation, but as it stands, I cant even blame it on something as mundane as a power surge, as they were never all plugged in at the same time.

Built in obsolescence accurate to the week?

Why are there no "built in obsolescence" conspiracy theories, involving the end of the Mayan calendar, and large software companies?

Oh well, we cant have everything.

I cant even have the correct plural form of "meltdown". I dont think it's the down-ness that's happening more than once, I think it's the melt-ness that is. So I'm changing my dictionary to read meltSdown.

120 things in 20 years is just killing time between computers, and editing dictionaries.

Electronics - My computer(s)

I've been having all kinds of fun with computers of late.

I've lost three in the last week. All of them old, but it's still a little on the strange side.

My workstation now looks like this.

From time to time I can borrow a little netbook, but if you don't hear from me for a while, it's because I don't have net access.

I'll do my best, but I'm not sure how often I'll be able to post for a little while. Currently I'm in the process of ripping bits out of all of them, and trying to build one that's at least partly functional.

It's not looking promising.

Anyone got a shiny new laptop they don't want?

120 things in 20 years is having temporary technical meltdown. As soon as the problem has been rectified, I'll need a holiday.

Aquaponics - Biological caterpillar warfare

My bialogical attack on my caterpillar problem is about to begin.

Pulling caterpillars from my tomato vines, and feeding them to the patrolling fish below was fun for a few days, but now I find myself spending all day hunting and searching for my little green eating machines.

There is an organic, and best of all fish safe solution provided by nature. It comes in the form of a bacteria called "Bacillus thuringiensis" and is sold under the name Dipel.

From everything I've read, it seems like a good idea, so I'm off to buy some and try biological pest control.

Aquaponics - Caterpillar

I enjoy sharing my produce with caterpillars as much as the next guy.

But these guys don't get the whole "wait until you've finished one bit before taking a bite from the next bit" thing.

Whoever wrote that book about the caterpillar munching it's way merrily through a stack of different pages full of valuable produce definitely wasn't hungry at the time. If they were, there would have been a very different ending involving being eaten by a fish.

Who would do this to a green tomato, and then move on to another .

I understand that you have to eat it before the next guy does, but all that waste! The way to take over the world is to get together with all the other bugs, and wait until the fruit is ripe like the humans do.

And then waste the food by tipping it into the ocean or setting fire to it so the market is protected.

Bugs know nothing of free market economics.

120 things in 20 years often aquaponics, sometimes pointless, but few would argue against my claim to it's number one ranking in the world of caterpillar politics and economics.

Aquaponics - My first tomato

I made a tomato.

And It's perfect.

It looks like this.

It makes me sad to think that if my tomato were part of some tomato making production facility, it probably wouldn't make it to the first grade bench. Not because there is anything wrong with it, but simply because there is too much individuality in my first tomato. Aquaponics has given it a really good supply of nutrients, but its fellow tomatoes are different sizes. Already they seem like their own tomatoes. Not towing the line and being totally uniform.

I wonder if there is a lot of nipping buds in tomato farms.

The fruit come on at all different times, but I figure if I cut out flowers for a while, then suddenly let them all grow, then cut out new flowers, I'd be able to get packs of six vine ripened tomatoes in a bunch all connected and all ripe at the same time.

Perfect to wrap in cellophane.

It seems like a lot of effort to go to to waste a stack of tomatoes.

Not that I can talk. I've been wasting many more then I'm letting grow out, in an attempt to leave some space in my little grow house for other things to also have their sunshine.

And just in case you missed it, here's another photo of the same tomato, but taken with a little more love, more accurately reflecting the feeling I have toward my first tomato I have ever grown in my life.

I feel like I've come of (middle) age.

I just made up a riddle...

How many lunatics does it take to photograph a tomato with love?

120 Things in 20 years - Not just un-natural tomato love.

Aquaponics - Instant siphon extension

One of the issues with rising sea levels is that you cant just pile up extra dirt and hope all your plumbing will still work.

Mine didn't.

As a result of the extra few centimeters of scoria I added, I lifted all the existing plants except the tomatoes. As I understand it, the tomatoes will just send down some extra roots from the newly buried stem, and all it will do is make them grow with even more vigor.

The rest of the plants may well now have their roots too far out of the wet stuff for their liking, so I need to lengthen the stand pipe, and the siphon to accommodate it.

For the bacteria to take advantage of the extra media depth, it needs the water level to rise, so the solution was an instant siphon extension.

The standpipe was easy enough, as a standard length of black poly pipe fit in the existing standpipe.

And I found that one of my black plastic pots fit nicely inside the siphon, and they are tapered, so I could jam it in to make it stick.

All it took was to cut the bottom out.

Drill some holes around the bottom edge to let the water flow through freely.

And finally, I jammed the narrow end into the siphon.


It even look good(ish).

Today on 120 Things in 20 years, rising water levels demand an instant siphon extension to be added to my aquaponics system.

Aquaponics - Ground level adjustment

As with some low lying pacific islands, from time to time, it's a good idea to make the ground a bit thicker.

It helps stop everything from dying, and makes everyone feel a little safer.

There has been a lot of settling out of the media in my grow bed over the last year and half, so we decided to finally get around to topping it up.

It will add some extra filtration, and also some extra space for root systems that are now getting huge.

When I dig anywhere in the bed now, I find tomato roots.

I had to lift the celery, and the capsicum (pepper?) plant to stop their stems from rotting, but left the tomato where it was. I understand you can bury a bit of tomato stem, and it will do the right thing and just send down some extra roots and keep on growing.

I'm counting on my two tomato plants to stick to that understanding, as they are currently the main feature of my system.

My computer decided that it didn't want to share any more, so there will be no photo's until it comes around to my way of thinking. In fact there might not be any more blog until it comes around to my way of thinking, or gets itself replaced.

120 Things in 20 years, just Aquaponics - Ground level adjustment

Aquaponics - Coz lettuce

My coz lettuce look fake.

I'm pretty sure they're not, because we eat them every day, but they look it.

In fact they look so fake I'm wondering if that's why the supermarket versions look the way they do.

Perhaps they leave out the iron or something in the plants diet so they look less like plastic lettuce and more like the lettuce I'm more familiar with.

My lettuce look so fake they actually look like a cross between spinach and cos lettuce.

But they really are cos lettuce.

Aquaponics - Peas

Peas are one of my favourite reasons for visiting my aquaponics system.

I don't grow enough of them to use them for meals, but just enough to snack on when I'm  getting some salad leaves, feasting on strawberries, or just sitting in the system enjoying the way my little eco-system plays out it's daily life.

I spend a lot of time in there watching.

Often watching insects, but sometimes just looking at my tomato ripening.

It's a slow kind of way to spend a few minutes.

It's even better when you are also eating a pea.

120 Things in 20 years - Just eating peas in my aquaponics system.

Aquaponics - Mini seed raising grow house success

It's well over a month since I wrote a post on seed raising, where I tried my current method for the first time.

I think it's a success.

I planted fifteen cups with perhaps two or three basil seeds in each. From that I got around thirty sprouts with every cup having at least one successful sprout. I'm not sure what the normal germination rates are for basil, but that's good enough for me.

The main advantage is that they are planted directly in the posts they will spend their entire lives in, so they wont get disturbed with transplanting.

I've since removed two sprouts and planted the pots with lettuce, with each one planted about 10 days apart. (a new lettuce cup is in there now to the left of centre) This means that, since the basil sprouted, I've planted, sprouted, and moved out two cups with cos lettuce in the time the basil has taken for the basil to have grown enough to be ready to move.

Here's one coz lettuce I just moved.

There are three seedlings in it, and I'm pretty sure I put three seeds in, so my method seems to be working fine.

I'll probably take the smallest one out, but my experience with three or more spinach seedlings in the one cup says it should be fine. I repeat harvest spinach and lettuce, so the plants never get to full size, but if one get's too big, I'll just harvest the excess and just leave one per pot. Whole small coz leaves make great Caesar salad.

This is another cos lettuce cup I moved ten days ago or so.

The cos lettuce seedlings I grew without covering the seed at all. I just dropped them on the surface, and put the lid on the mini seed raising growhouse. The condensation rain was enough to keep them wet enough to grow roots long enough to touch the water. That's enough enoughs.

It's also interesting that it's the original water in the mini seed raising grow house, that is now around five weeks old with no signs of it going off or tuning green.

So here is my official seed raising guide...

120 Things in 20 years Seed raising guide 2011        Page 1 of 1  

Put a seed on top of a pot filled with scoria.
Put the pot into a mini seed raising growhouse with an inch deep of fish tank water in it.

                      this space intentionally left blank


You can print that out and make a calendar with it if you like.

120 things in 20 years. Not just empty space and success with mini seed raising grow houses for aquaponics, but so much more.

Aquaponics Unhappy peas

I think my peas are officially unhappy.

They appear to be slowly losing their grip on the business of growing, staying alive, and making me peas.

Interestingly, this leads me to a question I'll be asking but not answering right away, because I'm yet to find out.

There are a few plant diseases that, once your garden contracts them, render your patch useless for that type of plant for some number of years.

It occurs to me that the soil must get infected.

It also occurs to me that I have no idea if the same would apply to growing plants in a media like gravel or scoria.

I'll find out.

Aquaponics - Tomato

There's not a lot of truth in anything you can say about gender differences, but I think men, as a lump, grow a lot of tomatoes*.

I suspect it's because it's colourful, plentiful, tasty, normally involves a lot of crap, and most of all, fast and easy.

I never liked tomatoes as a kid, or a young adult, but as I hit middle age I'm starting to think growing tomatoes is exactly what a middle aged man should be up to. I've been at it for only a few months, and already I've been pruning buckets of foliage, flowers, and even tiny fruit, as the two tomato plants threaten to take over the entire growhouse.

I've cut it back to something around the size of a large family dog.

But in the last couple of days I've started to see colour.

It looks like this.

And I'm getting a little excited.

I'm starting to wonder if people grow these things because they taste so much better than the supermarket varieties.

Of all the fresh(ish) produce you can buy, I'm guessing tomatoes, strawberries, and maybe bananas has been messed with most.

As a kid, I don't remember fresh bananas from Koki Market staying fresh for quite as long as the things I've had in the bottom my fridge for weeks, I also remember being a kid in South Australia where we had a large strawberry patch where you could hunt around for fresh strawberries, but if you ever picked a stack of them to take inside, in a bid to become more popular, they tended toward mushyness within only a few hours.

Tomatoes, I don't remember.

But I'm pretty sure they are not meant to bounce after months off the vine, and I'm also pretty sure they are not supposed to have all that white skeletal structure in them.

I hope they are as delicious as I'm building them up to be in my head.

*Really spell checker? You spell the plural of tomato tomatoes - see, not only did I not eat them, I didn't even write their name.!

An aquaponics tomato is just a tiny part of 120 Things in 20 years

Aquaponics - Exciting new mould

Just when things within the aquaponics system were going quite poorly, a new problem has dropped in!

Exciting, isn't it.

The universe saw fit to add some white powder-like mould to my peas, to go with the black, powder-like mould it provided to keep my strawberries company.

It looks like this.

Actually it only looks a bit like that.

That looks more like some white powder-like mould with some spray on it.

I forgot to take a photo before I dosed it.

And I also forgot to rig up a fan to circulate some air around my growhouse to stop things like mould outbreaks.

The spray is water mixed with a tiny bit of Eco-Rose.

Eco-Rose is a product that claims to be good for treating powdery mildew and black spot. It's also a product used to add potassium to aquaponics systems.

I don't know if I have powdery mildew, but it worked on the black mould I had last time.

I thought the black mould might be powdery mildew as well, so I cant see any reason why it shouldn't work on the white mould that I also suspect is powdery mildew.

In fact it should work better, because the black stuff turned out not to be powdery mildew after all, so I've very slightly increased my odds of being correct this time.

Which is nice.

120 Things in 20 years, offering slightly better aquaponics odds and exciting new moulds.

Thinking - Crane drivers

Once, at a place I used to work, a crane was required.

A man with five or six Bandaids, all criss crossed over his balding head arrived with a crane.

It turns out, when you transport your crane, you chain it's hook to your front bumper bar.

As he was setting up his crane and unchaining it, he suddenly stood up from what seemed like a normal part of the routine.

He was directly under the freshly released hook.

The hook whacked him on the head hard enough to draw blood.

He went to the the cab of the truck, and using the rear view mirror, and his first aid kit, cleaned the cut on his head and put a Bandaid on it.

It was then that realised I'd better start noticing just how hilarious everything is, and take it all in.

One thing I've discovered about the universe, is that dead people never notice anything.

I just thought you should all know that.

Don't forget to notice everything.

120 Things in 20 years - More often than not, nothing to do with crane drivers and thinking.

Aquaponics - Lady birds

That's not a real bird.

Some birds are more birdlike than others. Ladybirds  (lady bugs in North America) are hardly bird like at all. And they don't even rate on the lady-like scale (whatever that means)

The most birdlike aspect of ladybirds is that they can fly, and lay eggs.

The least birdlike activities include going through 4 different stages as they mature and mutate, being a savage cannibalistic predator in all but the egg stage, and generally being spotty, and featuring in a lot of children's books.

Whoever does their PR is a genius.

Their colour scheme for one is a delight to child and adult alike, but must strike fear into the hearts (or heart-like glubbs*) of aphids everywhere.

They should really be called "lady beetles" or ladybird beetles" as they are not actually bugs (or birds) , but are or course beetles.

They look like this in one of their stages.

And this is how that same ladybird larva looks in a soup bowl.

And this more familiar look in their adult version.

I'm told that they eat a stack of aphids (up to 300 in that first stage) but I'm often lied to.

But I actually think that's correct.

*yeah, that's a word now.

Glubbs (ˈfɜːfɪ) 
Heart like organ found within colourful, semi-spherical polka dotted fictitious insects, that whilst seemingly anti-aerodynamic in shape, can somehow fly (see magic)

Electronics - DIY waterproof switch build

It's a funny thing, but of all the wacky little inventions I've come up with since starting this blog, my DIY waterproof switch is the one I'm currently most proud of.

Here's how to build one.

I spent a long time trying to figure out a nice material to make a water proof, domed button out of.

I searched all over the place for ages until I decided to make myself a drink and found this inside my soft drink bottle.

I figured it would be perfect.

It already looks a little like a button.

I cut a 20mm hole in the end cap of the 90mm PVC tube that will house the electronics package for the demand fish feeder.

I needed to create a dome shape by pre-tensioning the gasket so I started by sticking the lid under the project temporarily with some tape.

This would allow me to press the button from the other side and hold it in place.

I added a large ball bearing to introduce a dome shape, and held it in place with vice grip pliers.

And the drink I'd made earlier.

And a box marked "Adjustable head magnifying glass".

Presumably, packaging for a device used to magnify heads.

I glued it in place and drank my drink through a straw until the glue set.

I figured with the ball bearing giving pre-tension, the glue should hold the gasket in it's new bubble shape to some degree,.

And it did.

This is the finished product from the inside.

Now when I mount a small tactile switch behind it, I should be able to press it from the outside so I can keep the electronics safe in a water proofed section of PVC.

It even works (if you can call that colour selection working (I was in a hurry))....

120 things in 20 years  Electronics - DIY waterproof switch build

All button pressing by Mrs 120ThingsIn20years
Mrs. 120ThingsIn20years is highly skilled at pushing buttons, and in the interests of domestic harmony, this should never be attempted at home.
Only one soft drink bottle was harmed in any way during this video production.
My drink was delicious 

Electronics - DIY water proof switch

Here's my home made water proof switch working, but I have to go out to dinner and don't have time to explain my switch.

And it isn't really a home made switch, just a DIY water proofer.

It looks like this, and I'm very proud of it...

120 things in 20 years - Not just an Electronics - DIY water proof switch that I'm very proud of

Aquaponics - 51 strawberries on a single plant

Is it normal to see 51 strawberries on a single plant?

I have no idea, but it seems like a lot to me.

Most of them are still in the tiny bud stage, but it still seems like a lot.

That's one of the best aspects of this aquaponics adventure. I keep learning new stuff even without study. I just wander out to eat something, and accidental learn something new.

Sometimes I learn that I don't have a clue what I'm doing, but that's good too.

Electronics - Final board layout

At last it's decided.

I've settled on a hybrid between the two previous designs for my demand fish feeder circuit board layout.

Now we have a small extra board set at 90 degrees for the two momentary (press them on then they go off when you let them go) switches, and the power switch will be on the battery pack.

The board also extends below the main board to allow room for some labels.

There will be three trim pots for in-field adjustment, and this will create settings for the maximum number of feeds per day, the size of those feeds, and the last will be to calibrate when dawn is detected.

I'm not really sure how I'll implement the dawn detection, but it will probably rely on some kind of requirement for an increase in light levels over an hour or something.

Due to the fact that I'm running out of pins to use on the PICAXE 14M2 chip, I only have room for two LED's (lights) to flash out the values for the 3 trim pot settings. This will be dealt with by by having the mode button switch between each 3 trim pots, and the normal operating mode.

The two internal lights will indicate the values by flashing.

  • When the "Feeds" trim pot is being adjusted, the green LED behind it will report it's value.
  • When the "Size" trim pot is being adjusted, the red LED behind it will report it's value.
  • When the Dawn trim pot is being adjusted, both the red and green LED's will flash out it's value.
In experimentation, this has proven to be quite intuitive, and easy to read. 

The dawn setting will probably never have to be adjusted once it is calibrated to local conditions to take account of street lighting etc, so was the obvious choice for not having it's own light.

The other two settings might be changed one a month or so, and as a result were deemed to be more important.

The placement of the buttons on the new circuit board, also allows for my absurdly clever water proof switch idea, allowing the "Feed Now" button to be pressed from the outside.

Which is nice.

The "Feed now" button will light the lever indicator light, telling the fish if they hit the lever some feed will be delivered. This function is in anticipation of the user (me) being overly excited about their new fish feeder, and wanting to see, or show others, the fish triggering the lever to receive feed. It will override the forced wait between feeds, but the feed will still be counted and deducted from their total allowed feed for the day.

120 Things in 20 years, not just Electronics - Final board layout, but also absurdly clever waterproof switch ideas!

Electronics - New revised layout

After a great deal of re-thinking (the shop didn't have the stock so I went with the old plan) I've decided against adding a second section of board at 90 degrees to the first.

My demand fish feeder will have to have it's original layout after all.

But I did manage to buy some 10k trim pots.

When you fry around in a plane, there is a way to make the plane do things like turn to the right, and a way to set the plane so it always turns a bit to the right. This allows you to keep the plane pointed slightly into the side wind so you keep going straight. This is called adjusting the trim.

I think.

I read that somewhere.

I cant fly planes or anything.

I just read about trim.

I think.

Anyway, I also think that's the kind of reason trim pots are called trim pots.

The pot bit is potentiometer (volume knob, variable resistor) and what they do is change the amount of resistance they offer depending on the position they are set at. These ones are set with a screwdriver and are normally used to fine tune or trim something before you close up the case and use the controls designed to be used by hand rather than a screw driver.

The 10k stands for 10,000 ohm.

Ohm is a measurement of resistance.

Wire has a low resistance, air has a high resistance, and people have a resistance somewhere in between. That's why we use wires to carry our electricity, and try to keep some air between the power lines and the people.

So when I set the dial on my trim pot with a screwdriver, my PICAXE chip sees a value based on the amount of resistance. The chip translates that into a number between 0 and 255. And then I write some software that says something like...

if its 0 to 9 then theNumberOfFeedsPerDay is 1

if its 10 to 19 then theNumberOfFeedsPerDay is 2

if its 20 to 29 then theNumberOfFeedsPerDay is 3


This gives the user the option to set up to 25 feeds per day.

So the device can be told that the user wants their fish to be fed, say, twelve times a day. As the user turns the dial, a light flashes out the value with a long flash for 10's and a short flash for units. So 12 would flash..

    Long   short  short

The device knows what the human wants, and the human knows where the device is at.

As for the new layout, it looks like the original planned layout.

The three trim pots are on the left with their LED's behind them.

Next is the mode button to switch between normal operation, setting the number of feeds in a day, setting the size of each feed, and setting how much light will be named as dawn, where the user happens to live.

Dawn will be the reset time each day based on light levels.

The last of the new components will be the power switch seen standing upright in the centre at the front.

Electronics - Header pin board

I'm not sure that "because I can" is a particularly good reason to do something, but on this occasion it's all I've got.

I think I'm going to finish my aquaponics demand fish feeder project with a new section of strip board, sticking up at 90 degrees from the main board.

There are these things called header pins that cost a few cents for a stack of them. They are just pins held together with plastic, and you can snap off the number you need. They come in all shapes and sizes and are useful for plugging things into, or turning entire boards into things you can plug into something else.

I used them on my first board (PICAXE 08M ProtoBoard) and ran wires to them from each of the pins, so that I could plug the board into my breadboard.

That's it sticking out of the breadboard at 90 degrees.

I need to add a pot (potentiometer/variable resistor/volume knob) and a light (LED in this case) to flash out the setting for two different numbers. The maximum number of feeds per day, and the size of each of those feeds.

I'm hoping it might look a little better than this piece of paper I have stuck on, but you get the idea.

I also need to add an on off switch to this project.

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