Aluminum can counter.

The Can Counter.

This is an old project I put together from old junk and parts I had lying around.  The motivation for this stems from my involvement in our local elementary school's bottle drive.  We collect cans and bottles from the local community to raise money for our school.  We sort the cans and bottles and then count them into bags.  Beer cans are 288 per bag, pop cans 288 per bag, plastic water bottles are 150 per bag and small juice boxes are 360 per bag.  Sometimes we can collect almost 10000 pop cans, beer cans, juice boxes and water bottles -- that is a lot of counting!

I've always hated the counting, so when I found a treadmill lying on the side of the road near our mailbox, I knew what I could make.  A can counter!  (As and aside, my neighbourhood isn't really so trashy, I think someone thought that maybe someone would want a free treadmill).

Free treadmill!

The can counter idea is simple - the cans are accelerated along the belt and then shot through a beam.  When a can breaks the beam, we know to count one can.  The beam is created by an LED shining on a photoresistor; an Arduino takes continuous analogue readings of the resistance.  When the resistance changes we assume that a can has broken the beam.

It was all breadboarded and then put in a fancy box.  The trick was to build physical guides for the cans to get them to line up in single file and to get the belt driving at a reasonable speed.

It actually works pretty well as you can see in the video.  Total budget was about $5 - I had to buy a belt to connect the motor.  Everything else I had lying around.

The video shows that the cans can be counted as fast as you feed them.  Much faster than by hand.  And it is quite reliable -- certainly counting cans manually, people get distracted and miscount.

Some problems with the counter which I couldn't be bothered to resolve.
1.  The motor is an old furnace fan motor, maybe from the 60's.  I might have been 1/3h.p. once but now is about 1/100 h.p.  So it can barely drive the treadmill and tends to stall.  I guess I could buy a motor, but that would increase my budget!  I think it puts some big emf spikes into the circuit too, which tends to mess up the LCD display sometimes.  Oh well, the price was right on the motor (free).
2.  If the cans are really, really close together, they might count as one instead of two.  But I think some creative coding could probably figure that out.  Or maybe a mechanical solution to introduce a gap to separate close cans.
3.  It can't count plastic bottles at all.  The beam break system doesn't work with plastic; it sees right through it, or counts the bottom, then the label, then the lid -- three bottles where there is only one!  Tightening the code to count only variations that last for a certain time might work.  Or add another beam from the side and compare values or a different colour that sees plastic better or.... I don't know, it would require more research than I care to do for a free, low budget project.
4. The hopper to feed the bottles onto the belt never really worked.  But then again, the budget was low ($5) so I didn't use anything other than scraps of plywood or cardboard for the hopper.  Again, a bit of money and time and it could have a pretty effective hopper.  I envision a top feed hopper with a powered paddle at the bottom to agitate the cans and feed them onto the belt! 

Protecting Our Cherries from the Birds!

I didn't see many bees in the fruit trees this spring, but I guess they must have been visiting the flowers because we have a bumper crop ripening on the tree.

Cherries ripening June 22, 2018.

Of course, the birds are a real threat to edible fruit (robins seem to be the worst).  The tree is about 8m high and I'd be happy for the birds to eat the high, out of reach fruit, leaving the lower fruit for me.  But, I know that they will peck, sample and destroy all the cherries if given a chance.  So what to do?...

Previous years I tried aluminum pie plates, scarecrows, CDs, holographic tape, scare eyeballs and blue survey tape to try to scare the birds.  The performance of these options was poor to say the least.

The best solution was using a motion sensitive sprinkler to scare the birds.  It worked but wasn't ideal.  The motion detector really didn't see the birds and the only way to scare the birds from the fruit was to dial up the sensitivity to the photocell to enable the sprayer to work constantly.  The water use was excessive and the deterrent not terribly effective.  Also, the sprinkler used a fair number of 9v batteries.

Last year I decided to make my own sprayer deterrent.  I attached an irrigation solenoid valve to an impact sprinkler head and then I programmed an Arduino Pro Mini to activate the valve every 60 seconds.   I also built a photocell into the circuit to ensure the system only fired during the day -- the birds aren't a problem at night!  The new system worked well, but was only effective on the lower branches of the tree because the sprinkler was stationed close to the ground.  And the birds figured out the timing of the valve and would attack in the lull periods immediately following the sprinkler activation!  Smart birds!  The whole system was powered by adapter, so I saved a few batteries.  And the activation time of the sprinkler was shorter, so water usage was less than before.  But it still needed improvement.

This year I decided to upgrade, and added a second impact sprinkler/solenoid valve.  I've built a tower of irrigation pipe with sprinklers at 2m and 4m levels aimed into the tree.  The Arduino code now fires the sprinklers independently and at random intervals.  The lower sprinkler and upper sprinkler are also randomly chosen to fire randomly.

Irrigation valve and sprinkler head.

So far the birds seem to have trouble figuring out the cycle and the cherries are ripening nicely without bird losses.  The sprinklers use about 250ml each activation.  So daily use should be about 100 to 150litres.  I figure that I might water the tree anyway so this water goes to good use making larger, juicier fruit. 

Future improvements might be to reduce firing frequency during certain times, because feeding pressure seems to be higher in the mornings and evenings, mid day sprinkler activations could be reduced.  I intend to etch some boards and build a few more as I've got 4 more cherry trees on our property that are unprotected.  This year is looking like a bumper crop, so much so that the kids are going to set up a stand to sell some cherries.

Many years ago I saw a bookshelf design on the cover of Fine Woodworking.  I'd been wanting to make the bookcase for many years now, but I didn't really have the materials available.  Last year however, I got some nice vertical grain douglas fir from a friend -- all thick stuff, 12/4 and the like, but with a bit of resawing on my bandsaw I was able to get the required panels for the backs and sides.  I even got the shelves cut from the fir and had a bit left over.  Thanks Sid!
Here is the end result which displaced our old, MDF cd racks.

First blog

I just thought that I would start a blog.  Just because.  So here it is...