Scaled-up Solar Tracker – proof of concept part 2

see part 1 :: see part 3

Pole top mount design

I’ve completed the design of the mount for the pole top and have asked a local supplier to make the parts for me out of stainless steel.

As you can see from the sketches, the design of the pole top mount allows the solar panel frame to be pointed further up or down, depending on the time of year.

Continuing the build…

Here’s the starting point for part 2 of the build

photo showing the starting point for part 2 of the design and build
starting point for part 2 of the design and build

The parts I was waiting for arrived:

  • the stainless steel pole
  • the lifter bearing – the short length of bar with the recess for the ball bearings that the lifting eyelets attach to
  • the 1:810 reduction ratio gearbox

The installation went smoothly – I used grease to hold the ball bearings in place while putting the lifter bearing in place.

I’ve now realised there’s a slight issue there as regards portability. It’s because the only thing stopping the bearings falling out (apart from the grease) is the bottom of the pole resting on them. And if the pole is to be removed for easy portability, the grease will cause some of the bearings to stick to the bottom of the pole. Hmmm….

Ok, onwards…

I coupled the 100rpm N20 motor to the gearbox and gave it a test. All went well and it was satisfying to watch the steel pole go up and down, twisting back and forth as it did so. It did take 6 mins or so for one complete cycle but that’s needed to get the required torque.

The next step was to try it out, building up to a weight equivalent to the final build and see how well everything coped. So I filled a 6 pint milk container with water and attached it to the pole as the first step.

I switched on power and, as it took the strain, the gearbox started to grind and stutter and then locked solid. Oh dear…

I removed and stripped down the gearbox and found the reason – a few teeth on some of the gears had broken off.

photo showing stripped teeth and damaged gears in the speed reduction gearbox
damaged speed reduction gearbox

So it turns out that the speed reduction gearbox I chose simply can’t cope with the required torque – it couldn’t even cope with around a quarter of the required torque 🤪

I’ve spent a good few hours online trying to find an alternative. I’ve fired off a few emails to suppliers of those that look likely, so we’ll see.

A reminder of the mechanism’s core requirements

The motor has to be driven by a single lithium ion battery, down to 3.7v

The motor has to be driven by a single 18650 lithium ion battery, down to 3.7vThe readily available TP4056 charging module can, with a small mod, detect darkness and then switch the motor on until everything is reset to the sunrise position
Absolute minimum of 2 120W solar panelsIdeally this would be 4 solar panels, giving an additional weight of 7.2kg, but 2 would do.
Torque needed at a minimum is around 3.5Nm (torque calculator)
The total weight of pole, frame, top pole mount and 2 solar panels is approximately 15kg, and the lifting force is applied at a distance of 45mm from the gearbox shaft.

If I can’t get a gearbox capable of handling the required torque, I’ll need to rethink a lot of the above. Fingers crossed! 😜

Where is Moji? A fun early-learners’ game app for iOS and Macs

I’m on a roll! After developing the More or Less app, it was easy for me to develop this new one.

Who is this game for?

I’ve aimed “Where is Moji?” squarely at early learners / younger pre-schoolers. It teaches them a critical skill: to recognise and then find one pattern hidden amongst a screenful of others.

To make it fun, I’ve chosen the emoji used in the game from

  • sports
  • animals and nature
  • transport
  • everyday objects

Dad and / or Mum can sit in and help them learn the names of the animals when they come up. Lots of learning opportunities are there to use.

For even more fun, when they find Moji, they’re rewarded with a funny cartoon sound and a visual reward of a fountain of coloured circles, cascading down the screen.

I’ve designed it so that the early runs and levels have fewer emojis, with the number increasing as the game progresses. If you’re feeling adventurous, you can try the setting for a big kids game, which has far more emojis and a faster bonus multiplier countdown,

The easy and hard modes I’ve included for both the Kids game and the Big Kids game means there’s always a challenge. What’s the difference? The hard mode has more emojis and a faster countdown so even if you have a great reaction time, you’ll struggle to hit the top scores.

Get yours…

Download “Where is Moji?” here:

See screenshots of the game and a demo video

When you start each run, the screen shows you the emoji you’re to find.

When you’re ready, tap “Go” and the level begins. Note that the emoji you’re to find is repeated just above the “Go” button in case, in the excitement of it all, you forget what you’re to find!

Kids Game: The emoji they’re to find is also shown in the scores panel

Take a look at this screenshot of the last level of the Kids Game (on the easy setting). It shows how the number of emojis has increased:

Kids Game: Run 4, Level 5

If you like, watch this video of a complete game being played on an iPad. It goes all the way up to getting on the high score table – with the cheer you hear when you do! (I’ve included a different high score table for BigKids, to keep them seperate.)

A complete Kids Game (on the easy setting) being played on iPad

Thinking about building an iOS app for Zazzle

We’re not quite sure what we can achieve via an iOS app and Zazzle so we’ve been digging around and having a play.

As part of that we developed a simple and fun app for iPhones and iPads aimed squarely at kids (big kids, too!)

It’s called More or Less Kid’s Game and teaches older preschoolers about the notion of more and less in a fun and exciting way.

Here’s a screenshot showing the core in action. In the previous screen to this one, the player was shown one of two emoji.

In this case (though you can’t tell) they were shown a flamingo. Now they have to decide whether there are more or less flamingoes than rhinos by pressing the More or the Less button. (Yes, we know it really ought to be more or fewer but we’re practicing being less pedantic!)

a screenshot of the main gameplay area of the More Or Less iOS app
A screen from our More or Less iOS app

If they don’t make up their mind quickly enough, after a short while the bonus multiplier starts to count down and the potential score for a right answer reduces.

If they choose correctly, they get a positive, funny cartoon sound and a visual celebration as a reward. The run score they get (the bonus multiplier X number of images) is then added to the total score for the level.

If not, they still get a funny cartoon sound – but no visual celebration and no score.

There are 5 levels and 4 runs per level.

If they play with Dad or Mum at their side, they can get help counting the emoji to find out whether there are more or less.

We’ve made it so that the earlier levels have fewer images with bigger differences between the numbers of each. As the game progresses, each level has more images and smaller differences between the numbers of each emoji shown.

Get More or Less here on the app store.

How can I get people to promote my Zazzle store?

We’ve added a new feature to Nifty to help your Zazzle store get promoted. You can now submit your store for promotion by the affiliates / artists that use Nifty as part of their promotion strategy.

screenshot of the store submission form
screenshot of the store submission form

When anyone submits a store, they’re first asked to pin/tweet/share 20 designs from a store that’s been submitted previously (chosen at random).

So there’s two ways to get promoted when you submit your store to Nifty, by:

  • affiliates using the new “pot-luck” button in the Nifty Promo Control Panel
  • someone submitting a store after you and your store gets chosen as the one to have its 20 products pinned/shared/tweeted

All good quality stores are welcome. Submit yours if you like – the sooner the better! If you think about it a bit, it’ll make sense…. stores submitted earlier have a slightly better chance of being chosen.

Submit yours here

Goodie “Easter Eggs” now in the free version of Nifty for Zazzle

Only for those who don’t pay a Nifty subscription: you might, if you’re very lucky, bump into one of the “Easter Egg” goodies we’ve added.

Wait, what’s that?

It’s just a bit of fun but we’ve hidden a bunch of “Easter Eggs” in the Nifty Promo Control Panel. Each one is something you’ll love – so far you could get:

  • one of the various time-limited free subscriptions to Nifty
  • one of your collections listed in Nifty’s featured collections panel

We’ll be adding more as time goes on 😎

Here’s what one looks like:

what an "Easter Egg" looks like
An example of one of the “Easter Eggs”

The more you use Nifty, the more likely you are to bump into one. Good hunting!