So, I produced this quick paper accordion model to go with the paper bellows but it does nothing beyond looking pretty.
I really wanted it to make a sound. Proper accordion sounds are impractical in a project this size but a bit of discordant whistling would keep me happy.
To the drawing board!
I've learnt through my various past experiments that a whistling pipe needs a tapering blow hole blowing air over a slot. I fitted some baffles inside the hex box (black lines above) to direct the air and fitted a tapered blow hole lined up with a suitable slot. The result: perfect whistling! 1046hz according to the app on my phone. Roughly a 'c' two octaves above middle 'c'
The downside being the big sticky-out-bit on the side of the box. I wondered if I could fit the tapering tube inside the body of the hexagon.
And so we have this. Air, to be provided by bellows, blows though the hole in the side of the box through the tapering tube and across the underside of the slot at the top of the picture above.
Once assembled and with the glue dry the finished box sounds a nice clear whistle. I'll make another with a different note by moving the baffles inside to change the volume of the resonant cavity and fit that at the other end of the bellows.
With the bellows in place a quick test shows that everything is working nicely so far...woot woot!
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A set of paper bellows/springs to download and make. Members can download the template at the link, thanks for signing up! There are three designs in the template file, pentagon, hexagon and nonagon (9 sides) Check out the previous blog post if you would like to design you own with a different number of sides.
Print out the pages onto standard printer paper, not card. Score along all the dotted and dashed lines then cut out the page along the surrounding line. You may have to set your printer to "Scale to Fit" to ensure that the whole template is printed out.
The three pages look like this.
Pre-crease all the dotted and dashed lines before you glue the parts together. These instructions are illustrated with the six sides spring but apply equally to the other two.
Glue along the back of the edge opposite the grey area.
Roll the tube round and glue down exactly on the edge of the greay area.
Okay - now this is fiddly and a little tricky. Take your time.
Starting one row of parallelograms from the top. Pick a parallelogram. Fold the centre diagonal as a valley fold and the four surrounding edges as hill folds.
Once done move onto the next parallelogram on the same level and repeat the process.
Work your way round to complete the row.
Repeat the process with the next row down.
Work your way right down to the end.
Complete the spring/bellows by folding in the ends noting that the hill and valley folds are swapped in the ends compared to the main body.
...now if I can just fit some sort of sound generator, perhaps a whistle or two, into this mini squeeze-box...
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Friend of the website Edgar pointed out this fun design on the Instructables website. The download with the article was the template of a pentagonal spring. In the pictures, other designs of spring were shown but no templates were provided. Below, I have presented the techniques for creating your own spring with any number of sides.
The template for the five sided spring looks like this. The spring is divided into five vertical sections, the sixth, grey, area is where the sides overlap to make a tube.
Each unit of the spring is made from a parallelogram divided diagonally with a crease line.
The sides of the parallelogram are all the same length. In this case, 38mm.
To calculate the angle of skew of the parallelogram it is simply a matter for dividing 360° by the number of spring side - in this case 5 giving an angle of 72°
360/6 = 60° for the six sided spring.
and for the nine sided spring. 360/9 = 40°
I'll be uploading templates and instructions shortly for those of you who want to try your own.
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The whole point of video is the movement. It is what differentiates it from photography. Videography of a static subject comes to life then the camera is moving, however subtly. By moving the camera round the camera the solidity and depth of the subject becomes apparent. That's the theory. To that end I'm working on a way of steading my camera while I pan round the paper model I'm filming. I have an old generic gorilla pod to which I plan to fit wheels. Here's the story.
After a bit of experimenting it turned out that the rubber feet on the end of the gorilla pod legs covered a plastic cap. I pulled off both the rubber and the cap and discarded them
I now had a hollow hemisphere to which I wanted to bolt the wheel. I was concerned that the part would be crushed by pressure from the bolt so I decided to fill the space with Milliput. First of all I scratched the inner surface of the foot to give it a rough texture for the Milliput to key onto.
Milliput is a moldable two part epoxy cement.
It is used by thoroughly mix equal measures of the two parts. The resulting putty sets hard in two to three hours.
I mixed up enough to fill each of the three feet.
By slightly over filling each of the hollows I was able to apply a slight convex surface to each foot.
Once the Milliput was completely cured I drilled a hole through each foot using an 8mm drill bit.
A suitable bolt (75mm M8) fitted though the hole and a washer was added to ensure that when I fitted the wheel it didn't bind with the leg. The wheels I used were a set of 72mm roller blade wheels fitted with suitable bearings both of which I picked up on eBay.
I added a second washer then bolted the wheel into place with a lock nut. The bolts were slightly too long so I cut them down to size with an angle grinder.
Two more wheels and the job was complete.
And there we have it. I fitted the camera to the top, lined up the wheels so that the whole dolly moves in a circle centred around the subject. It is all looking good. The angle of the wheels can be changed quite subtly allowing the radius of the movement to be changed. The legs bend and flex allowing the height of the camera to change and it is fairly straight forward to point the camera down at the angle required.
I should have some film up shortly.
<--- edit ---->
I planned to add this project to Instructables.com. Turns out some-one got there before me.
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It's been a while since I've had a special offer on memberships so I thought I'd set up a Spring Special! Happy spring to everyone (in the northern hemisphere).
Membership Plus - 20% off! Enter the code MPLUS on checkout.
Standard Membership 10% off! Enter the code MEMB10 on checkout.
More details about Memberships and what you get with each are here.
Both of these offers are valid until 31st March 2013 and apply to both new and renewing members. Thanks for your support! As you know, I literally couldn't run robives.com without you!
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I've been working on a new way to create Zines. The current version that I've used for previous zines such at the Lever Zine, here, is based on a single sheet of paper folded and cut. It works well but has some limitations. Firstly as it is to be printed out onto a single sheet, the individual pages are small. Secondly, each zine is restricted to exactly eight pages, no more, no less.
The new layout I have come up with is not restricted in the number of pages in each zine. Also, the page size can be up to almost half of a sheet of standard printer paper though I have used a quarter page size for this prototype. It still maintains the advantage of being easy to print out, printing is required only on one side of the paper. The new design also has the advantage of being make-able with scissors only. No knife is needed.
Each leaf of the zine, two pages, front and back, is made from a single shape, shown above. The dimensions are shown here, if you are a member you can download a blank template with two of these on a single sheet for you to try out.
The main page units fold up like this...
... and are joined together by gluing the long tab to the back of the next page.
I used a single rub from a glue stick on the back of the sheet...
...then glued the edge down to the tab.
With four (or however many you want) of these units glued together the final zine spine is made by folding the last remaining long tab over the edges of the book centre (1) The sheet which will be the back cover of the book is then folded down and glued to the long tab.
And there you have it. Eight page zine, ten page zine, twenty page, whatever you like. Easy to use, easy to make.
Expect to see a finished zine in this new format soon!
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Three seven tooth pinions surrounding a fifteen tooth central gear. This project is from the Gear Zine (coming just as soon as I've finished all the projects it contains!) The project demonstrates the use of small pinions made from double thickness 2D card.
The file of parts is free for members to download, thanks for signing up! Non-members can download the parts for £2.50. Print out the parts onto thin card. (230 gsm / 67lb) The first two sheets work well if printed on coloured card. The remaining two onto white card. Score along the dotted and dashed lines and cut out the holes before carefully cutting out the parts.
Join the two rim parts together using the grey area for alignment. Make sure that they are straight.
Start from one end, gluing the teeth to the grey areas on the rim.
Use the black arrows to help with alignment.
Glue the next section of teeth over the top of the last piece of the previous teeth.
Glue all three sections of teeth to the rim leaving the very last piece unglued.
Glue the rim closed then glue down the last tooth piece.
Make up the wheel inner as follows:
Glue the two triangular stiffeners to the grey areas across the centre of the wheel. Repeat the process with the second wheel.
Glue the two wheels back to back with the stiffeners running perpendicular to each other.
Fold up and glue together the axle. Thread the axle into place.
Fit the wheel into the rim and glue the twelve tabs into place.
Fold the pinion pieces in half and glue them together to make double thickness card. Make sure that you don't glue the centre tabs down.
Once the glue is dry, carefully cut out the gear and fit the axle into place.
Fit the axle alignment piece into place top and bottom. Use the grey lines for alignment.
Assemble the two base parts as shown.
Push one base piece into the other pushing it home completely. Glue the two flaps down to hold the two parts together. Glue the four legs onto the base.
Roll up the four pins so that they fit snuggly in the square axle tubes.
Fit the pins into the axle tubes.
Complete the model by fitting the pins into the holes in the box. Turn the centre gear and the outer pinion gears spin quickly!
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Another page for the Gear Zine...
This time about using mixed 2D and folded tooth gears. For gears with few teeth (in this case, 7) the faces of the teeth need to be curved. These are known as involute gears. I'm using double thickness card to construct 2D involute gears.
I wanted three smaller gears spaced equally around a central gear so there was a bit of geometry involved :-)
By adding the radii of the two gears I knew that the distance between the centre of the larger gear and each of the small gears was 57mm. I planned to make a T shaped base (in red above) Fitting the lower gear and first gear was simple, I just space them by the 57mm.
The other two require a little geometry. I'm spacing the pinions evenly round the central gear, so that is one every 120°
That makes the angle opposite 'a' = 30° so I can work out height 'a' as sine 30° =0.5
0.5 x 57mm = 28.5mm
Length 'b' is calculated the same way but this time with the angle being 60°
sine 60° = 0.8660
0.8660 x 57mm = roughly 49.5mm
With piece the parts laid out, here's how it looks. Again I've made the support piece from the same colour card as well background so it blends in.
...and here it is in a mock up of the zine so far.
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For the next page of the forth coming Gear Zine I need a small drive gear to run against a larger gear. I've decided on a seven tooth gear. The teeth on smaller gears need a more pronounced curved surface than do the teeth on larger gears so I've opted for a gear made from double thickness card where the teeth profiles can be individually cut.
I've gone for the same round pin in a square tube layout as the other gears. The addition of the two green pieces hold the gear square against the axle.
And here's the result. Looking good so far!
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