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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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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