Electronics Aquaponics Demand feeder lever

Probably the most difficult single thing to deal with in making my demand feeder has been working out the lever.

But as usual I called upon chance to solve it for me.

Thanks chance.

For some reason I remembered playing with a switch I bought when I was making the first version of this demand feeder. The switch was one that is a button, and turns on then off again after you lift your finger.

Its sideways click seemed nice to the touch.

The one pictured (centre front) is the same, but is on an old circuit board. I cant find my original version.



Its quite long for a momentary switch.


The interesting thing about these particular, particularly long momentary switches, is they they do their switching thing if you tilt the button to the side rather than just press it. I just tested this one and it works.

They also work if you press it, but its the sideways switchyness that interests me. It should be perfect as the lever the fish hit, because they can hit it from any direction and it should trigger.




Now all I need to do is figure out which brand they are, and if they all work like that. It might be the case that only some of them do this. It might be a manufacturing error rather than a feature.

Perhaps manufacturing error is too harsh.

Perhaps manufacturing  tolerance would be better.

Either way, I might be able to use it.



120 Things in 20 years - As luck might have it, for the next few days, you might find me in electronics stores with a multimeter, trying to find a switch for my electronic, aquaponics demand feeder lever.

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Photography Seeing whats inside a canon auto focus lens

Opening up my old camera in an attempt to fix a stuck lens didnt end well, but it did make me want to open other stuff.

A mouldy $5 canon EF 35-80mm zoom seems like a good candidate.

I actually made it work better than it did when I started.

Thats officially a successful repair.

We dont see many of those around here.

Odd feeling.

It turns out I wasnt being all that original when I used a lens cleaning cloth to make my macro lens hack light tight. It seems canon does something similar with a rubber band.

I attacked the rubber grip of the lens by lifting it up with a small flat head screwdriver, and sliding it up to reveal the three screws that control the zoom function.




Once that was done, the lens started falling apart. All it took was finding where the screws were in the first place. All the places I was told to start by the Internet were all false leads. Im guessing things like lenses are made by the lowest bidder at the time, so these things probably change design all the time.

The only real stumbling block was this very fragile looking plug.

Luckily I had uncounted them when I pulled apart my point and shoot canon digital, and discovered they werent really all that fragile.

I covered it with a folded bit of paper so the pliers wouldnt scratch the circuit off and pulled.




I also tried to avoid touching anything that looked like it might be copper. I have a feeling that touching stuff might lead to corrosion.

Probably just being paranoid, but it wasnt any really effort to avoid it. I should buy some cotton gloves for this kind of thing.

The little plug looks like this when its unplugged.

Robots are probably better at putting stuff like this back together, so I took a lot of photos as I was unbuilding it, so that I might have a chance of putting it back together.

Thats a tip.

Take lots of photos of things as you pull them apart.

One part that was really fragile was this little bit of kit.

Its like a switch that drags its contacts along a curved section of circuit board tracks so that the contacts keep in contact when you rotate the lens to zoom.

Or perhaps they adjust the aperture as you zoom, as Ive noticed the available aperture range changes from one extreme of zoom to the other.


Who knows what its really for, but I bent it convincingly out of shape when I was putting the thing back together.

I managed to fix it, but two of the pins will never be the same again.

This is the rear element. (the bit you can see a lens in on the left)

Its a cluster of ... three I think it was... lenses (two at least, but I think one was made of two), that I think also contains the aperture control.

The aperture control stuff must be in there, because there was nothing else with electronics in the lens.

I think this is me taking apart the lens that was really two lenses.

This things all had mould, but the other side of the one you can see in this pic had the most.

This is what I decided was the aperture bit.

I hope this isnt too technical for the reader.

Is bit even a word in this context...

Anyway, the remarkable thing is, after wiping down all the lenses with a lens cloth, it was actually an improvement.

Thats the before and after shots with this lens.

Most of the milkiness is gone, but there is still a bit of mould on the front bunch of lenses, but I think I might hack them off and convert this thing to a macro lens.



Ive been reading up on lenses, and how to hack bits off lenses that you dont want, and turn them into lenses that you do want.

Anyway, not a bad outcome for a $5, brand name, auto focus, zoom lens.

I cant wait to cut bits off it.




120 things in 20 years - Where you will still find someone who thinks a lens doing its auto focus thing is excitingly like having a robot. You also might find someone interested in photography trying to open a lens to see if there really is a man inside who does the focusing. (theres not by the way)

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Making smoked foods Soldering iron cold smoker

I bought some very inexpensive cuts of chicken labelled "Breast roasts for two" from my local supermarket.

They appeared to me to be a prime candidate for value adding.

I brined them in a solution of water, salt, sugar, pepper, and some lemon juice. I also threw in a couple of bay leaves. I have no accurate record of the measurements used.

Measurements are a tricky thing, because you cant rely on one batch being the same as the next. The amount of meat, and its existing water and salt content create differences. You can probably ignore the existing levels, but the amount of meat being brined changes things a lot. The result is you cant just say x amount of water needs y amount of salt.

As I understand it, the process of absorbing the salt and sugar is done by osmosis. Salt is removed from the water, so the amount of meat in the brine changes how much salt is left in the brine. The result is the solution might need to be stronger to brine more meat. Irregular shaped meat like my chicken breast still on the bone, requires a bigger amount of water to cover it.

The good thing is, it will probably work well no matter what you do, but it does make a recipe a bit pointless.

That being said I used about 6 litres of water and a bit over half a cup of both salt, and sugar.

Brine your food in cold water, in the fridge.

After an hour and a half, I removed the chicken, pat it dry, and placed it into my lidded BBQ.

A 12 or 24 hour brine would have been better but I was pressed for time.

I also placed my trusty tin can full of holes inside, and jammed a 60watt soldering iron* into it at the base.

Perfect, cold smoke in minutes.

A total success.

The wood chips were from a store bought pack of smoking wood chips.





Im pretty sure this would ruin the soldering iron for soldering, but this was one Ive never used as it was way too powerful for anything I might do.

Previously I used my tin can full of holes with burning heat beads to keep it going, so I needed quite a few holes to support the combustion required to keep it alight. With the soldering iron, I can choke it down a lot more because it will never go out. I think Ill make a new tin can with less holes, and a large adjustable hole in the top by way of two lids with large holes that I can rotate to make whatever size hole I need. This should allow total control over how much smoke is made, and with some marks on the lids, I should be able to keep a record of what setting it was on, and what worked and what didnt.

But it does seem that everything works, no matter what you do so dont be too stressed over recipes and instructions. Just have a go, and you wont be disappointed.



120 Things in 20 years - Should have done a bit more research before trying to make a cold smoker because a soldering iron works really well.


*using a soldering iron for a cold smoker is NOT an original 120 things idea

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Electronics Aquaponics Demand feeder fish lever build

I spent some time in an electronics store testing long buttoned momentary switches.

They all seem to work when you tilt the button to the side as well as when you press the button normally. Perhaps they are designed to work that way after all.

Thanks button maker.

I had a bit of a breakthrough with the entire lever, and not just the switch part. I found this fishing float had a white plastic bit that almost fit over the momentary switchs button.

Thats the switch lower right.

The white plastic thing was hollow, but needed a slight enlargement with a hand held drill.

The button went in with a snug fit, and the white thing was really their just to give me some surface area glue onto.

The new lever incorporated a second fishing float as the stem, and as a nice bulb for the fish to hit.

The float stem has a bit of flex to it, so it should be forgiving if a fish hits it hard.

It looked lie this when built.

I glued it in place with super glue, and held it while it dried with what to me looks like a naked chicken with a fist for a head.

So now my device looks like this.

It also works.

I turned it on, and while I was putting a cover over the fish tank, the bigger of my two fish hit the lever and got a feed.

I did have the camera running, but the video was too dark to post, but the switch and lever worked perfectly.

I count this as a success!











120 Things in 20 years suggests you never try to take your electronic aquaponics demand feeder on a plane with you, unless you feel like explaining it for a few hours.

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Heliostat Whats a heliostat

I want to start building a heliostat, with the eventual goal of making a solar tracker, but for now, I really want to just build something that will send light through my window.

Why? You may well ask.

And "Whats a heliostat?" you may add.

A heliostat is the kind of thing someone with a water drop lensed microscope might have used to get some light on the subject*. Early models involved humans, who were forced to point shiny things in such a way as to reflect the light to shiny mens laboratories. Later versions incorporate wind up mechanisms. For a single day device, all thats required is that it turns 15 degrees every hour, as long as you are willing to manually adjust the elevation for the particular day you are using the device,
a heliostat will track the sun so that a mirror will always reflect to the place I want the light.

The solar tracker is like a heliostat, except that the place its pointing at is always moving. (that point being directly at the sun wherever it is. But the solar tracker is for another day. Actually all of this is for a great many days.

For now, Ill be working on a small digital device that controls the direction a small mirror is pointing, to make it always reflect light to a fixed point. Basically a way to bring some natural light through a window that doesnt see a lot of light.

There seems to be a few different ways to create some linear movement. Linear movement being required to lift a side of the mirror to adjust the direction of the reflection in the up and down aspect.. I figure if I can raise or lower one side, and make the entire device pivot around a mast, I should have all the degrees of movement required.

According to the invention engine, one way to create the required angle might be to glue a hinge to a mirror, and mount that to a mast to support it. Tie a string to one side of the mirror, then wrap it around a tiny winch mounted half way up the mast, then tie the other end to the other side of the mirror. That would give me up and down, and then all I need is a way to rotate the entire device, perhaps using a geared motor, and a pulley.

I havent really tackled this bit of the design, but the control of the motors could be done via a PICAXE chip similar to that used in my demand feeder. and some light dependant resistors (LDRs).

If two LDRs were arranged so that when the device was pointing correctly, they were both in full light, but when one became shaded, the motor could be turned in the correct direction to make the adjustment.

A similar arrangement could be made for both the up and down, and rotational movements.

Im off to an electronics store to buy some stuff.



*may not reflect reality.

120 Things in 20 years is busy finding bits of heliostat. 

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