I've put together a first draft of the Keyboard Kat mechanism. Click on the picture, left, to see it in action. It still needs a bit of work on the movement, for example, the arms need to lift a little higher but apart from that I'm pleased with how it is going. I hope you like it too!

 


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Sun 24th Apr 2016

Late stage prototype for the cat part of the Keyboard Kat model.
I've added a head. No sides on this prototype yet but they'll be added later. I've also changed the design of the arms, bending the elbows inwards moving the hands closer together. Finally I have shortened the body and added legs.


The pull straps work nicely for moving the arms up and down. They protrude through the base of the cat and will be connected up to a pair of cam followers.


With the cat seated on a suitable piano stool the straps will be hidden from view.
Next: The base and cams. The project seems to be coming together quite nicely :-)


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Thu 21st Apr 2016

Inspired by all the piano playing cats on the internet I'm working on a cam powered keyboard playing cat model. Here's the sketch. Turn the handle and the Keyboard Kitty pounds at the piano keyboard.


My plan is to have two weighted cam follower in the base, one for each arm. When the cam is in the down position it will pull the arms upwards. When the cam follower is lifted the weight of the arm drops the arms back down again. Because the arm is operated with a pull rather than a push I can use a simple strap to operate the arms rather than having to make a rigid push rod. Hopefully this will make the mechanism simple to construct.

Here I've put together a prototype arm with a linkage and axle.


In my prototype I've fitted each arm into a separate body half. This allows the two axles, one in each shoulder, to move independently.


A simple wide strip of card joins to the two side together.


Pulling each strap raises the approriate arm. Just like that!


Here's my artist impression of how it might all fit together.


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Thu 14th Apr 2016

robives.com is based around the Drupal content management system. This makes it flexible to use and easy(ish) to maintain. The time has come, though, to move from Drupal 6 to the latest version. This is a fairly major undertaking so I'm using it as an opportunity to upgrade the look and feel of the site and streamline the membership system. The new website will have all the same content and features plus it will be responsive, the technical term meaning it will resize to fit whatever device you are viewing it on be it laptop or smart phone. I'm also hoping to add $US pricing in the download shop.

Please bear with me over the next couple of weeks as I poke around on the website internals - I'm aiming to keep disruption to a minimum but just so you are warned...

Also, if you have any feature requests, now would be a good time to ask :-)

Rob


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Wed 6th Apr 2016

I'm experimenting with ways of tuning the pipe on the twitterer project so that I can hopefully create a bird box automata where the bird sings a song with changing notes.

I've tried two different ways of tuning the pipe. Firstly, with an outer sleeve that moves back and forth, this works in the same way as a trombone hanging the length of an open ended pipe. It works fine and the pitch changes maybe five or six semitones between the extremes of travel.

My other option was to use an inner piece that worked as a piston. This inner tube is blocked off at the end inside the main pipe. As it moves it changes the length of the closed pipe. It work really well and has over an octave of pitch change between its extremities. This is the option I'm going with, next to connect it up and move it via a cam shaft.


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Twitterer Type 3

In the previous blog post I showed a design for a crank driven bellows to be used at the heart of a bird box project. I have taken that basic design and made it more sturdy. I liked the way the bellows in the previous model were completely visible so I've fitted the crank to the inside of a box but kept the bellows on a pair of slide rails outside the box. You can see the result in animated action on Instagram by clicking the picture to the left.

If you are a Member or a Patron you can download the parts for free, thanks for your support! Non members can join in the fun for a small fee.


The first page of the file needs to be printed onto normal printer paper. The remaining pages need to be printed onto thin card (230gsm / 67lb) I used coloured paper and card for a colourful model. Score the dotted and dashed lines. Cut out the holes then carefully cut out the parts.


The push rod ends are made from double thickness card. Fold them over and glue them down. Once the glue is dry cut out the hole and cut out the parts,


Assemble the push rod and glue the push rod ends into place.


Roll up and glue down the three axle tubes.


Fit the shortest axle tube into the push rod.

Make up the two crank pieces.


Glue the crank pieces to the axle. Leave a small gap between the crank pieces and the push rod so that it remains free to turn.


Fold up and glue the flaps on the box pieces making triangular tube sections.


Assemble the sliders.


Glue the slider to the glue area on the box side making sure that the holes are lined up accurately. The large arrow in the glue area points up to the top of the slider.


Glue together the two box sides. Glue down the top flaps on the box but not the base flaps.


Assemble the handle as shown.


Make up the bellows top and base by gluing down the card to make double thickness.


Glue together the two parts of the cross piece.


Thread the crank into position and glue in the two remaining axle pieces.


Glue down the base flaps then glue the side flaps to the inside of the box.


Make up the two sleeves.


Thread the sleeves into position.


Glue in the cross piece keeping it as square as possible.


Turn the model over and glue the push rod tab to one side of the crosspiece inner.


Glue the handle into position.


Make up the pipe body and pipe end.


Glue the two parts of the pipe together lining up the end with the glue area on the body. Blow through the pipe to make sure it works. Make small adjustments to the position of the pipe end if necessary before the glue dries.


Glue the pipe to the bellows top plate lining it up over the hole.


Before starting the bellows pre-crease as many of the folds as possible. Roll round and glue down the paper to make a tube.

Starting from one end fold down one row at a time observing the hill and valley folds marked on the paper.


Glue the bellows end plate to the tabs on one end of the bellows.


Glue the other end of the bellows to the bellows end plate with the pipe.


Once the glue is dry glue the tabs on the bellows end place to the inside top of the sliders.

Let the glue dry then glue the bottom of the bellows to cross piece to complete the model. Let the glue dry completely


Turn the handle and fill the room with a keening whistle!


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I've made some progress on the birdbox project. As I'm sure you remember, I'm working on a paper version of the old Victorian singing bird automata. There are limits to what I'll be able to acheive in card but already I think I'll be able to do more than I had originally planned. As I progress through the design process I am releasing various prototypes as downloadable models for you to try at home. This stage looks like a likely candidate for the next downloadable project.


The pipe is at the left hand side connected to the top plate of the bellows. The bellows are my new non-rotating design with their other end connected to a sort of sliding cradle. Turn the crank and the cradle is pumped back and forth blowing the whistle making a fantastic clean tone!


I envisage the final layout being something like this. I'll be releasing the crank/bellows mechanism for your own experimentation shortly.

Next steps:
Vary the pitch of the whistle, probably via a cam.
Connect up the birds wings and beak.
Fit everything together!


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Over Christmas I was working on a set of new book for publisher Hungry Tomato. They have just appeared on Amazon ready as pre-order items. The Tabletop Wars series is a collection of fun projects that you can make from everyday items you find around the home. From trebuchets to to marshmallow land mines the books have all sorts fun to make projects based on a tabletop warfare theme. I've designed the projects and artist John Paul De Quay has illustrated the instructions. Look out for the books in August this year!

As this isn't about paper projects I probably won't mention it again on this website until the books are released. If you want to find out more follow me on Instagram where I will be posting pictures of some of the projects.

 

The four books as they appear on the UK Amazon site - search for "Rob Ives"

 

A table top ballista from the book Make Your Own Seige Engines


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The bellows part of the Bird Box Project have caused me some difficulties. The problem was that as the bellows are compressed they twist. This made it difficult to mount them inside a mechanism. I've come up with a solution to the problem which I outlined in my previous blog post.

I'm now making both the new and the original designs available as a download so you can try them out first hand. Click on the image (left) to see and hear both types of bellows in action.

If you are a member or a patron you can download the parts for free. Thanks for your support! Non-members can also join in for a small fee.

Print out the first two pages onto standard printer paper. The third page has the parts for the end plates and the pipes. These need to be printed onto thin card (230gsm 67lb) You will need to print this page out twice to make both models. I printed it onto two different colours of card then mixed and matched the parts to make colourful models. For both the paper and the card score along the dotted and dashed lines, cut out the holes then carefully cut out the parts.

 


Making The Pipes

You need a pipe for each model. Fold round and glue the pipe body.


Fold and glue the pipe cover.


Glue the pipe cover to the pipe body lining it up with the grey areas.


Two pipes ready for action.


Bellows: Original Design

Before making the bellows pre crease along the fold lines.


Form the bellows tube by rolling it round a suitable size bottle and glue down the end as accurately as possible.


Start from one end. Working down a row at a time crease the bellows following the hill and valley folds marked on the paper.


The end pieces are made from double thickness card. Fold them over and glue them down. Cut out the marked hole on the top piece.


Glue the ends into place on the tabs on the bellows.


Glue the pipe into position over the hole. Let the glue dry completely before trying out your bellows.


Bellows: New Design

The design works in the same way as the original design but every other row of creases is flipped left to right. This cancels out the rotation and makes the bellow's movement parallel. Try to pre-crease all the fold lines, it is harder than on the other design but worth the effort.


Form the bellows by rolling the paper round a suitable bottle and gluing the ends down as accurately as possible.


Start from one end. Work your way down one row at as time creasing the bellows by following the hill and valley folds marked on the paper.


Glue the end pieces into place.


Glue the pipe into place over the hole. Wait until the glue is completely dry before you try out your bellows, you don't want to blow off the pipe!


Seen below are both types of completed bellows.

My next step will be to mount the new design bellows into some type of crank mechanism. Should be fun!


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Next step in the bird box project. Bellows and crank. Turn the handle to pump the bellows. This is similar to the type three model I made before but the guide rails will keep the moving plate horizontal as it moves. There's a problem though.

As the bellows move back and forth the plates twist in relationship with each other.

 

This is the net for a section of the current bellows design.

My thought was that if I flip every other row side to side, the rotation in the end plates should be canceled out.

Here's the new layout.

It takes a little long to score the bellows but the end result works perfectly. No rotation at all!

 

Here are the two test bellows side by side. Next step - connecting up the crank.


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