Electronics - Aquaponics - Demand fish feeder software

As far as I know, the software is all working on my demand fish feeder.

It's a bit of a mess, with a few goto statements and a few unused variables. I'll fix it in time, but for now I'm going to move onto getting a finished product up and running. As far as I can tell with the software simulator everything works, but the real world might be a completely different story. (the breadboard version also works)








A switch lever extends down into the water. If a light near the lever is lit, the fish can press the lever and feed is delivered. Feed can also be offered with an override button that sets the light on and the feed on if the fish hit the lever (so you can show people how it works)

Dawn detection seems to work. In the end I went with two startup options.

1. A human who holds down the FeedNow override button during startup, then taps out the approximate number of hours since dawn. This skips the code that searches for a new dawn.

2. An abnormal restart with no human. This stops all feeding (there might have been a blackout, and subsequent ammonia buildup) (note to self - add code that flashes some lights to indicate the device is in abnormal start mode so a human can reboot it if they desire). Feeding resumes after night time is detected, and a dawn is detected.

The user can select (via a screwdriver to resist little finger making their own adjustments) ...

 - the feed amount per day in tenths of a second of motor on - from 0 to 65 (I'm guessing I'll use 1/2 a second per feed event) The motor turns an auger under a hopper full of feed. So there is another adjustment available

- The number of feeds in a day that are offered (0 - 255 per day)

- The level of light at which dawn is detected. This allows for a system built in the glow of a streetlight or whatever. At dawn each day, all the numbers reset. This is a bit of a problem as far as reading how many feeds were delivered in a day, but for now I'll leave it as it is. My fish feed like crazy at dawn, so I want to give them the greatest opportunity to feed. Eventually I'll add a data logger, so it wont matter when it resets.


The system reports...

- the number of hours since dawn

- the number of feeds since dawn

- The number of false hits to the feed lever when the FeedIsAvailableLED is NOT lit (these will go down to near zero once the fish learn they can only get food when the light is on)


I ran out of feed a while back, and have been feeding my two big silvers on duckweed, lettuce, and worms, so I will need some pellet food before I can test it in the real world. (I still have the PVC device from the first version).

I'll also need a motor as my original one is no longer with us.

The feeding regimen isn't very intelligent at the moment, but I'll do a bit of research, and add some code that tries to deliver the maximum amount of feed in a day that the system can handle. This will probably involve allowing 3/4 of the feed to be dumped at will, with the rest being spaced out over the day ... or something. I haven't given it enough thought because I don't really know what the fish need. My experience in fishing for wild fish indicates that the feeding pattern is far from a constant grazing all day long. I'll work it out.

But...

It's going to work. In fact, it already does.


120 Things in 20 years That's all. Just 120 Things in 20 years.

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.

Electronics - Aquaponics - Demand fish feeder proof of concept

So the aquaponics demand fish feeder works.

Or at least the proof of concept bit works. Not the PICAXE and electronics bit.

The PVC, the motor, the hopper, and the screw all seem to work well together.












It looks like this....



This is just me touching the wires to a battery rather than the electronics triggering this, so the amount it is delivering each time is a little random.

But it will work just fine.

Yay.

Now, where did I put my education. I really need some of it now for the electronics.

I wish I had paid attention in school.

Electronics - PICAXE vrs Arduino

I've been madly reading everything I can get my hands on to compare these two mini computer systems. 

Scanning electron crayon image of actual electricity

Arduino is an open source platform where a stack of different people build lots of different bits that all plug into each other and do all kinds of amazing things. You program them in a computer language called "C".


PICAXE is a company that does lots of work with the education system in the United Kingdom, which is run by a queen, and is programmed in a computer language called "BASIC". [the chip not the queen]


She's also the queen of Australia. 


Which is odd. 


I'm not normally a fan of non-democratic state organization, and the queen is far from democratic. But I'll buy stuff from her country in spite of all that. As far as I know the people of PICAXE don't actually know the queen or have anything to do with her. And she does seem like a nice enough old lady. 


So I'm going with PICAXE.


Another reason I'm going with PICAXE is they were the first people I found, and I've already read a lot of their manuals and things. They are also cheap (to buy bits from, not as individuals (well maybe, I have no idea)), have a good reputation for prompt delivery, and the big seller from my point of view, they make a board called a shield base that is open source compatible. I think that means I can use the best of both worlds. 


A shield is a pre-built device that talks to, and plugs into, the main device. So if you want to control something like a fan in a glasshouse, you can use a thermometer connected to your main device (that might be called a shield base), then plug the motor control shield into it. This way you could perhaps turn the fan on in the glass house if the temperature got over 30c or something. The bit that controls the higher voltages of the fan, can be all dealt with without me having to reinvent the wheel. 


I'll be reinventing the wheel though, as I want to learn electronics. I'll probably end up using a bit of everything. 


A lot of people have made a lot of different things that already do interesting stuff, so you can plug that interesting functionality straight into your project.


But doing something like using a shield is a long way off. I have to learn to solder, and make pickles first. I suspect my first real world project will be to revisit my automatic fish feeder, that the fish operated by pressing a lever.


So, in short, PICAXE seems to be able to do whatever it is that I think I might want to do, and wont cost very much. Cost is important, because my entire 120 Things in 20 years have to be self financing. I borrowed the set up cost of the aquaponics system from myself, and roughly work out savings based on the supply of vegetables etc. coupled with some advertising revenue and my aquaponics pump and other goodies I won from the photographic competition, After buying my glasshouse and some extra plumbing, I have just enough left to refill the sugar bowl after making my first marmalade, and start on my new electronics "thing".

Aquaponics - Pest control automatic fish feeder

I have an idea.

This one was inspired by irritating people, and just how much my fish enjoy eating bugs. It  also involves a deer scarer, and some green plastic.

There are these things you can buy that attract bugs to them because they are a shade of green or blue that fools bugs into thinking they are going to be even more yummy than your veggies. The green ones no doubt are a leaf colour that's attractive, and I'm guessing, the blue ones are some ultraviolet thing.

Some bugs see into the ultra violet bit of the spectrum, or so I'm told by TV, and its never been wrong about anything before.

But the point is they are sticky. When your sticky green square is covered in bugs, you bin it, and get another.

My plan is to get some green stuff that isn't sticky, and point a deer scarer at it so that every minute or so, it suddenly pours water over the green plastic and washes any bugs into the fish tank. I was thinking of perhaps bending something green into a PVC pipe that sits up near the grow bed, but empties into a fish bistro below.

Less bugs and happy fish. A win, win, lose situation everyone except bugs can enjoy*.

I have no idea if it will work, because I have no idea how long the bugs would hang around on a bit of green plastic if it wasn't sticky. But I suspect, that if the little deer scarer washed it often enough, it would work. It might also be the kind of thing a moth might like to lay eggs on, and I'm guessing my fish would enjoy some moth caviar every now and again. At least I'm sure they would enjoy it more than my plants do.

I have no idea if it will work, and even less of any idea as to how I might tell if it has worked, but I think I might make one, and find out.



*I actually quite like bugs, and appreciate their motivations, but I maintain, that their freedom to express their buggyness ends where my lunch begins.

Aquaponics - Duckweed auto feeder

I've had an idea.

Duckweed grows at an amazing rate. It also seems to spread out to take up the entire surface available to it. This appears to be a function of surface tension. But I may well be wrong so don't quote me on that. In fact, don't quote me on anything.

Because of the way duckweed spreads out over it's available surface, it should be possible to use that, and various other handy attributes of the universe, to make an Aquaponics duckweed auto feeder.

Here's what the original plan looked like.

The pump for my new aquaponics system will be on a timer, and will run for around 10-15 minutes each hour. When it runs, a small amount could be diverted to the duckweed auto feeder. The diverted stream could be applied to a PVC pipe  in such a way as to divide the floating duckweed. If required, the stream could be shaped so it spreads across the width of the PVC, and perhaps points away from the standpipe. If the stream is set to spray across the top of the water, it will keep the majority of the duckweed away from the standpipe, but still allow the water to pass under the stream,through the standpipe and into the fish tank.

Here's the animation that might make it understandable.

Aquaponics - top down view of duckweed auto feeder 

• When the water flows in from the sump pump, a small amount of duckweed is separated from the majority, so that it moves toward the standpipe (to the left) and the rest is kept away to the right.
• The water overflows into the standpipe, into the fish tank.
• The overflowing water takes a "dose" of duckweed with it to feed the fish.
• The size of the dose can be determined by the placement of the water inflow. Moving the inflow further to the right would increase the duckweed dose, to left would decrease it.
• Because the duckweed spreads out to occupy the available space, the dose would be a percentage of what remained rather than a set amount. This means you should never run out of duckweed. If there isn't very much in the system, only a small amount would be delivered.
• The duckweed will grow faster in summer when the silver perch want more feed, and it will grow slower in winter when the fish are not so hungry. The faster it grows the more the system will deliver on each pump cycle.
• If required, a thinner PVC pipe would allow for better fine tuning to allow a smaller amount of duckweed to be delivered each time.

Once it's set up, it should largely regulate itself.

My plan is to make a large bed of water to grow duck weed in, using goat dung for nutrient, and create a duckweed auto feeder connected to my fish tank, that I can scoop some duckweed into every few weeks.

Here's a side view animation 

Aquaponics - Goats really are fun

My goat broke my automatic feeder today.

I guess it tasted good, but it might have been more polite to just eat the fish feed and leave the switch alone.

And so far the only gold I have found in all that gravel was this.

It's an interesting crystalline substance that, up close,  looks like plastic gold jewellery, mixed with crushed glass.

I've never seen fools gold before.






I don't feel foolish.

Other than that, everything at the auction I went to was selling for way too much so I'll forget buying a purpose built fish tank, and go back to the original plan of buying some IBC's.

IBC's are how we humans move our ever growing numbers of litres of liquids needing transport across the world. They are generally white(ish) plastic and take the form of a cubic metre drum in a cage on a pallet.

Make sure you know what was in them before you buy them. There is a stack of toxic stuff moving around the globe in these things on any given day. Luckily, many of them carry things like soft drink syrup. Many are not food grade plastic, and its a good idea to check for cracks and flexibility as they become brittle after too long in the sun.

Aquaponics - String feed counter

The small volume of the food that's being dumped each time my on demand feeder triggers makes it difficult to measure, so I've been trying to figure a way to register trigger events.

My fist attempt at measuring the times when my fish triggered the feeder was a small spot of blutack on the top of the shaft. If the shaft moved while I was away, I could tell. But it turned out that the shaft turned one full revolution on at least one occasion, so there was no way of know if the fish had triggered it or not because the blutak was right back to where it started.

The next was a small pebble that I could leave sitting on the top of the shaft. If triggered, I would find the pebble lying next to the shaft. This worked but could only measure one trigger event before I would need to notice it, and reset it.

My latest design is a piece of string attached to the shaft, with a nut on the end for a weight. When the fish trigger the demand feeder, the string winds around the shaft, and raises the nut up.

It wont tell me exactly how many times it was triggered, but will give an indication of how long the motor ran in the time since I last reset it. Each time the fish hit it, it seems to turn approximately one revolution, so I should be able to mark off a rough guide on the wood. This should make a reasonable gauge to tell me how active the fish have been in setting off the feeder.

Aquaponics - Demand fish feeder success

I think I can safely say my fish feed themselves now.

Its been only five days since the fish first set eyes on my on demand feeder, and in the last 12 hours they have triggered it around eight or nine times.

They seem quite casual about using it now. Although The smallest of the fish in the tank just lurks near the lever, looking up at it. This little guy spends almost all his time looking at the lever, waiting for someone else to press it.



Water tests are showing no ill effects from the new feeding method, although I wouldn't expect them to. Feeding gradually all day rather than in large lumps a few times a day, should see the ammonia load maintain a nice steady level. A stable ammonia level, in my case zero ppm, should allow for the bacteria to maintain a relatively stable population. As far as I can see it should make the system a little more forgiving, and generally more stable.

Another advantage is that there should be less wasted food. With my regular method of hand feeding, I fed the fish until they stopped eating the feed. This meant that every time I fed them, a small amount would be left uneaten, to sit on the bottom. This represents no great loss because uneaten food all turns to plant food in the end anyway, but the plant food may as well go through a fish before being eaten by the plants.

My next step will probably be, to add a hopper to feed the auger. This will only need to be something like an empty soft drink bottle upside down over the PVC chute. While I'm at it, it would be a good idea to weather proof and possum proof the entire device.

All in all this experiment has turned out to be a complete success.

The cost for the motor and gearbox was around AU$20. I used a short length of flexible plastic tube to connect the gearbox shaft to the auger, which I already owned.

Aquaponics - Silver perch feeding themselves

Success! After only 2 days the fish are now regularly pressing the lever to activate the fish activated feeder.

Aquaponics - fish fed fish

1. When you feed your fish, it becomes obvious that they remember you. Or at the very least remember the food jar they see when you are about to drop food into their world.

2. When I put a 10cm length of plastic tubing into the fish tank to measure my fish against, I noticed the fish would peck at it enough to move it around the tank.

These two points lead me to the obvious conclusion that I need to make a fish feeder that the fish themselves control.

I can trust them.

If I can make some kind of lever that sticks down into the water, and connect that to a motorised fish feeder, I should be able to teach them to feed themselves.

I should be able to train them by waiting near the lever, and when they get near, press the lever for them. I'll set it up so that the feed drops right next to the lever to encourage an association between lever and food.

Once they start hanging around in roughly the correct area, I'll reduce the distance so they need to get closer before I trigger the lever for them. I'll keep reducing the distance gradually until they have to be right up against the lever before I trip the lever.

If I stay disciplined, and don't cave in and feed them even when they are miles away from the lever, I should gradually see them getting closer and closer to the lever whenever they are hungry. They should also start to hang around the feeder, rather than swimming toward me whenever they see me.

Waiting until they get nearer and nearer each time should get them used to the idea that food comes from the lever area.

When they are regularly hanging around the lever, I should be able to stop tripping the lever for them and just wait until one of them hits the lever either by accident, or because fish just peck at stuff.

Once one of them has the hang of it I'm convinced many more will pick up on it.

I'll still have to regulate the food supply so that no more than my system can process is fed to the fish in any given day. This should be possible by only putting a day's worth of food in the hopper. With regular testing of the water, and keeping an eye on how much they take, I should be able to work out if I can trust them with ever increasing amounts of food so that perhaps I could set up the system with enough food to last 3 days or so. I would want to set the maximum amount of food in the hopper to a level that even if all of it got dumped into the system all at once, the system would still be safe.

Now all I need is the device, and a willing fish.