RIX Living Lab

Here is a preview of new version of the multisensory cushion controller box. Unlike the previous version, which used an Arduino Uno and Adafruit Waveshield, this one uses a Lilypad MP3 player and is powered by a LIPO battery (not shown in the images). The battery is plugged into an Adafruit lipo charger, which is permanently connected to the MP3 player. The Lilypad MP3 player has built-in amplification which is loud enough to power the Visaton K50 speaker without needing an external amp. This new controller box is about 20mm thinner than the last version, and shorter. The whole controller box is 140mm x 70mm x 25mm and about 100g with the battery.

Preview of cushion controller

We have been experimenting a little more with the laser cutter and tried out a variety of settings for engraving photographic images. The early attempts were either too dark or had poor image resolution, and it turns out that the latter depends largely on how well the image is converted to a bitmap which the LaserScript can use (1-bit bitmaps only). A fellow laser cutter from the LaserScript forum (Dave) converted a photo for us which worked really well when we engraved it, so we did the rest of the images in a similar way. Using Photoshop, we scaled each of the photos to 15cm x 11cm, converted them to greyscale and then saved as a bitmap using diffusion dither at 300DPI. The settings on the laser cutter were: speed 300, power 20 and scan gap 0.05, with bi-directional mode switched off. This gave a really clear engraved photo, though on reflection I think we could probably have increased the power to 22 or 24 to make them a little darker. Perhaps we’ll do that for the next batch. One nice little trick we have learned is to tape the wood down to the laser bed using masking tape to keep it flat – simple, but effective!

Here are some of the results of yesterday’s cutting and engraving. In the first image you can see the pieces of the boxes we are cutting out for the sensory labels. The image does not do the actual items justice – they’re much nicer than this in real life!

Cutting out the box parts, and engraving the photos

Closeups of the sides and tops:

Top panels of box

Sides of the box (holes for sound)

Here are couple of closeups of the engraved photos:

Holding a cup

I like the one below as a concept – an engraving of Tim holding his engraved image. An engraving of an engraving.

Tim showing his engraved picture

We still have a batch of parts to cut and some more photos to engrave. Then there is the big task of assembling all of them and adding the electronics.

A few of the original engravings didn’t turn out as well as we’d hoped, mostly because the line drawing were too thin or too light, so didn’t convert well to 1-bit images. We asked the group members to do the drawings again, but with a thicker pen/pencil and make them as large as possible on the paper.

The images were scanned at 300 dpi, converted to greyscale, thresholded to get the clearest 1-bit image and then saved as 1-bit bitmapped images. The size of the image was set to 15 cm x 11 cm, and the images inverted.

On the laser cutter, we set the speed to 200, power to 20 and scan gap to 0.05 for engraving. This was a bit experimental, but appeared to work well for the 3mm birch plywood. As you can see below, the resolution of the engraving is really good, and the images came out really well. They also feel good to touch, with clear outlines.

I have since learned that there is a simple method for calculating the correct scan gap, for a given dpi of image. It is:

DPI to Scan Gap = 25.4/DPI

For example, a 300 dpi image would then have a scan gap of 0.085 using this formula. I’ll be try a slightly lower dpi on the next engraving, and so reducing the scan gap and seeing how much different this makes to quality and speed!

All four new engravings

Sams Shell

Katy’s Snake

Ashley’s Bird

Adalana’s Ring

Each of our co-researchers from Tower Hamlets was given the task of drawing their favourite (or preferred) object from the enlightenment gallery at the British Museum. The drawing was to be kept simple, as we wanted to engrave each one onto wood and then use this engraving for the front, of what will eventually be, their sensory box. Each of the completed sensory boxes will eventually be placed alongside the real object in the enlightenment gallery for our (one day) exhibition in January. the process for engraving is described below.

Each of the images was first scanned and saved as a greyscale image. This is one of them (drawn by Ryan):

Ryan’s scanned image

The images were cropped to 15cm x 11cm and set at a resolution of 300 DPI, as we wanted them to be approximately the same size as a postcard. The images need to be converted to 1-bit bitmaps so that they are compatible with the laser cutter software. This was easy to do in photoshop: first change image mode to greyscale, then set the mode as bitmap. Then you can save the image as a 1-bit bitmap. We also inverted each of the images to get:

Ryan’s picture inverted

The reason for doing this is that the laser cutter will remove the background and leave the sketched lines as a relief. We prefer this way of engraving as the result is much more tactile.

Here’s the machine which we used to engrave and cut out the pictures:

LaserScript LS3060 laser cutter and engraver

It’s a LaserScript LS3060 with a 60W tube. It’ll cut 8mm acrylic or plywood, possibly even 10mm. For the engravings (and the box which is decribed below), we used either 3mm birch or 3mm poplar plywood. The poplar is slightly softer wood so requires a lower power setting. However, we didn’t know this at the time, so the poplar engravings appear darker than those cut from birch.

The picture were merged into a single large bitmap which is approximately the same size as the cutting area of the laser cutter. This allowed us to engrave and cut a whole batch of images, rather than one at a time. It took about 1.5 hours to complete each set of engraving from a sheet of plywood, and the results are shown below:

Images engraved using birch plywood

The second set of engravings used poplar plywood, and as you can see they are darker:

Images engraved using poplar plywood

We also created a very simple box which has the same length and width as the images so that an image can be attached to the front of the box. The one below has dimensions 11cm x 15cm x 3cm and is just about deep enough to include some simple electronics, including a speaker, MP3 player and battery:

Prototype box cut out using the laser cutter

When assembled, the box looks like this (this one has an engraved image attached to the top):

Prototype box with an image attached

Here is the first print from the new CubePro 3D printer. It’s a case for an Arduino Uno, using the standard print resolution. It’s a little rough around the edges, which might be that the printer platform is not quite calibrated correctly, or perhaps the objects itself need some further work. However, it’s not bad for a first attempt, and impressive that it includes a functional hinge. I can’t help wondering how the printer managed to build the hinge without any supports …

3D printed Arduino Uno case, using the CubePro.

The LBGL modules have been extended to include 6 new ones, as in the image below:

Set of LBGL modules ready for testing out with our group this week.

From top left: pulse, toggle switch, motor, servo, pulse (duplicate as the original one is flakey), pressure sensor, light sensor, bargraph  LED, sound trigger, LED, vibration motor, bend sensor, power module, RGB LED and push switch.

We will be testing out these modules this week on our Tower group, to see how well they  understand what each module is intended to do. We will start by giving them a demo using a simple push switch, as we assume they are already familiar with this object (though I think we should still ask them first to tell us what they think it does). Then we’ll let them experiment as a small group (6 people) to find out what each modules does. We’ll video the session so that we can review it later. We’re hoping to find out which modules offer the best affordances, and also generate ideas for improving the modules which are difficult to understand.

Another version of a pig in a bucket, produced by Rachael McGowan. In this design, instead of squeezing the ears or nose (like Rachel Hallisey’s pig) this one grunts and jumps about when you stand near it. The pig is made from papier mache and will sit on top of a platform near the top of a bucket. The platform moves up and down and takes the pig with it. Here is the original pig (which is used, not reproduced):

The pig that will be go into the jumping pig bucket

The original idea for making the pig move around was to use solenoids, but solenoids with a decent plunger reach (the amount of movement) are expensive and require a lot of current. So instead, we opted for a high speed servo. The mechanics are shown in the next few images. We first cut the bottom out of the bucket and fitted a wooden base, and glued this in place. Two holes were also cut at the sides of the bucket which supports the metal pivot. The pivot rests on 3D printed plastic supports (not shown here, but in the next image) that fit through the sides of the bucket, and act as bushes:

Base fitted to bottom of bucket, and pivot for moving platform

The servo fits onto the base:

Servo attached to base

The servo is then connected to a lever assembly which attaches to the moving platform, and rocks on the pivot:

Servo mechanism

The next image shown the platform in position:

Platform on top of pivot

The pig is not attached to the bucket but is free to jump about on top of the platform. We put grass on the platform and let the pig roam free! The video below shows the working model:

The ‘Hole in One’ bucket is Luke’s creation, and is the result of the workshops in which our group explored what they could do with buckets, boots and baskets around a rural theme. Luke plays golf regularly and so wanted this to be reflected in his creation. The original is below:

Luke’s original Hole in One design

To reproduce the design, we cut out the top from a sheet of plywood (rather than cardboard as Luke’s original design):

Cutting out the top

The top is just large enough to fit over the bucket with a small rim:

Top for ‘Hole in One’ bucket

We then used a hole saw to cut out the hole in the top, and also to cut out the hole for the tube from which the ball (or egg!) appears. The tube will be connected to a short down pipe which is hot glued to the top.

Bucket with hole cut for tube

The next image shows the down pipe (yet to be trimmed) glued to the wooden platform that fits at the top of the bucket and which the flexible tube will connect to:

Wooden platform with down pipe

This sits on top of the bucket and wedges between the handle posts:

The wooden platform on top of the bucket

Before adding the tube to the down pipe, we added an IR LED and sensor which will trigger the sound. The IR LED points directly at an IR phototransistor (they are matched and so have the same wavelength). When a ball is dropped down the pipe, the beam is broken, and this is converted into an instruction which triggers a sound:

IR sensor. The opposite side of the pipe has a matching IR LED

The sounds are grouped into two sets of three, and each set can be selected by inserting one of the two flagpoles into the top of the bucket. Each flagpole has an RFID embedded in it, and the top of the bucket has an RFID reader. Originally we anticipated a lot more sounds which we wanted to group into different sets, hence the use of the RFID and reader. However, we eventually honed down the number to just six. It’s a novelty, which would be used to extend the scope of sounds in the future. The image below shows how small the RFID pill is – it is placed next to a 6mm diameter wooden dowel:

The RFID before being inserted and glued into the wooden flagpole

The video below shows the Hole in One bucket:

This has been a long time in the making, and we have finally got to the stage where we can add the chicken to the mechanism and electronics. The design is a chicken (made from papiermache) sitting inside a hand basket, and Rumena wanted it to cluck and flap its wings like a chicken. That meant we had to find a way of attaching wings and then making them flap at the same time as generating the clucking sound. Here is Rumena’s original concept at the centre front. It is the yellow and red one between the bucket and the boot and the head is pointing towards the left:

The chicken-in-a-basket

The sound player is straightforward and is an Adafruit WaveShield attached to an Arduino Uno. Most of the objects we have creeated have this setup, as it is easy to work with and inexpensive. Also, I personally like the WaveShields as they have a simple design and so easy to understand. I have build around 40 of them.

The original mechanism for flapping the wings was based around a crank that was attached to two conrods, and which operated two levers attached to the basket. But this was too bulky and would not fit under the chicken. So, instead, we opted for a high speed servo. The servo pulls and pushes on levers attached to dowls which are themselves attached to the basket, but can rotate. It’s probably easier to just show the image below:

Mechanism for operating the wings

The wings are then attached to the dowels and can flap backwards and forwards, but only by around 60 degrees of rotation at most. the servo is controlled using a Polulo Micro Maestro, as this makes it easy to control via simple serial commands sent to it by the Arduino Uno:

Testing the servo controller

The whole flapping/clucking is triggered using a sonar attached to the Uno. Moving within 1m of the chicken will trigger it. In the image below the sonar is hooked up to the Arduino Uno, and the Arduino is connected to the servo controller (not shown). The sonar is a very inexpensive off-the-shelf HC-SR04, which has a range of about 3m.

Testing the sonar

The next image shows the whole setup with the servo and controller too. Note the simple mechanism to operate the levers on the basket.

Testing the servo and sonar

As with most of the other objects we have created, the audio uses a 3.5W kemo amplifier, and a 5W Visaton speaker The whole thing is shown in the image below:

Basket, complete with flapping mechanism and audio hardware

At the top centre of the previous image there is a voltage regulator. This is a replacement to the original, which was faulty and consequently I managed to fry two servos before sussing out that the voltage regulator was kaputt. In fact, one of them actually went up in smoke as I was on a Skype call with Kate!

Two ex-servos now leading an aimless existence

The Chicken was a bit floppy as it is made from papier mache, so Kate stuffed it to make it a bit more robust and so that the head would stay in place:

The Chicken was a bit floppy, so Kate stuffed it to make it a bit more robust.

The wings were attached to the two shafts that protruded from the top of the basket, and which are directly connected to the servo which makes them flap. We covered the mechanism with the lining form the basket, and attached the sonar (distance sensor) to the front of the basket so that the chicken would start flapping and clucking when someone stands in front of it:

Adding the wings to the basket

Finally, the chicken was fitted into the basket! The egg at the side of the basket contains the giant battery that powers it.

Chicken in a basket (a.k.a. Rumena’s funky chicken)

Here’s a video of the chicken when we tested it out: