Sparky Jr.

Instructions

Download Printable Instructions (pdf updated 10/4/09)

Download Outer Shell Pattern (SketchUp Doc)

Download Internal Shelf Pattern (Zip)


Part 1: Computer Hardware


At its core Sparky Jr. is a Wifi-enabled computer riding on a Roomba vacuum. The reality is a little more complicated, but not much. The computer and monitor get power from a small 12 v. battery, and the iRobot has a serial connection to the computer so it can receive commands to drive the wheels and use its sensors. All together, this assemblage of hardware becomes a unique machine – Sparky Jr. - A wireless rover capable of face-to-face video chat anywhere in the world over the web.


Older versions of Sparky were made from trash, found objects and discarded technology. Sparky Jr. can still be made with a wide range of found or scrounged hardware and components, but this one was created with a mix of new and existing materials.


Here is a list of the basic hardware I used:


For the ‘bot
Mac Mini computer
Lilliput 7” VGA car-puter monitor
iRobot Create robot chassis
Keyspan serial to USB adapter
Logitech USB desktop microphone
Creative Labs Ultra webcan VF0060
USB powered speakers
12 v. 7Ah hobby battery
100 watt inverter Cigarette lighter female socket
Small hardware corner braces
Assorted small 10/32 nuts and bolts
Assorted Erector set parts
Thin plastic sheet


For the control computer:
Any web-enabled computer with webcam
Chat headset
Logitech USB Game pad


Tools needed:
Hotglue and gun
Drill/driver and bits
Zipties Scissors
Matt knife
Screwdiver


Optional:
2nd monitor (for setup)
Table saw/drill press
1/8 and 1/4 “ Acrylic plastic
Acrylic solvent



A) Sparky Set-Up: First set up Sparky’s Mac and monitor as you normally would, as well as the webcam, speakers and mic.. Also plug the iRobot Create into the Mac using the Keyspan serial/USB adapter. We will test this connection later while setting up the software.


B) Control Computer Set-up: This should be straight-forward. You can use any computer with a webcam that connects to the Internet and can handle videochat. It can be a desktop, laptop or netbook. I personally chose a Dell Mini 9 netbook with a hacked Mac OS installed. This computer will have the USB game pad and the USB chat headset attached. Install Skype.


C) Fire up Skype and test that all these components are working. You may need to go into the preferences pane and make adjustments.


D) Once the computer and Skype are working, shut everything down and plug the Mac and monitor into the 12v. battery using the cigarette lighter inverter. The 3-prong mac plugs in directly and the monitor can use the included lighter adapter. Restart the Mac and test it again. Everything should work the same as before until the battery drains – you should get at least an hour or two on a full charge.


In my experience, the Mac Mini does not always retain every preference and setting, so each time I turn Sparky on, I manually adjust the monitor resolution and screen orientation as needed, as well as the audio input and outputs.



Part 2: Software


Currently, our controller software runs only on a Mac, but the next version will work on both Mac and PC, which will allow a wider range of hardware options.


If the text on your Sparky monitor is too difficult to read because you are using a small TV instead of a VGA monitor, you may want to use a second monitor for the software set-up. Once it is complete, you can switch back to Sparky’s permanent monitor.


A) Download and install the Keyspan driver onto Sparky’s computer. Follow the instructions provided by Keyspan.


B) Download the Sparky Jr. Joystick installer. Put this on the computer that you use as the "control booth."


C) Download the Sparky Jr. iRobot Server installer. Put this one on the Mac Mini onboard Sparky. These installers will place several files on your system as well as an icon on your desktop. I recommend putting the Skype and controller icons in the dock next to system preferences for easy access on both computers.


Test the software: Do the following steps in this exact order


1) Place the iRobot Create on a block, so the wheels can spin freely
2) Make sure all the hardware is connected on Sparky and control computer
3) Hit the iRobot Create “ON” button
4) Turn on both computers
5) Start Skype on both computers and sign in. (each computer needs an account)
6) Start the Sparky controller on each computer and hit the connect button.
7) Make sure the messages in the Sparky controller window indicate a connection.
8) Move the joystick forward once or twice. The wheels might spin immediately, but it might take about a minute’s lag for the first command to respond. Once it begins, there should be no lag between commands and response.



Once everything is working, the hard part is over and the fun creative part begins. Carefully disassemble the robot. Keep track of all the cables, hardware and parts.



Part 3: Structure and Outer Shell


Sparky Jr. is designed so that it requires just a minimum of structural parts to hold all the components. The outer shell is made from a single sheet of flexible plastic, which becomes rigid and strong enough to act as an exo-skeleton once assembled. Sparky’s monitor and speakers are attached to this shell and are completely supported by it.

The other structural part required by Sparky Jr. is a small internal shelf to hold the Mac and other components in place. It can be made of many different materials, including wood, plastic, and metal – even Lego or Erector set parts will work. But I recommend building it using acrylic or Plexiglas. The results will be strong, lightweight and clean. The pattern is available for download at SparkyJr.com.



Inner Table:

Download the zip file containing the template for the shelf and print them out. Make sure you print at 100% (even if the printer warns of cropping the image). Measure the image to confirm the proper size.


If you are using wood or metal, construct the shelf your own way. If using acrylic, carefully trace the pattern onto the material and cut the pieces using a table saw with fine wood blade and drill press with plastic or fine wood bit. ¼” thick material is ideal for the legs, but the top and feet are 1/8”. If you had to choose a single thickness, go with the ¼”.

Some people point out that cutting and drilling plastic and acrylic can be tricky without special tools or blades. It’s true that you must be careful, but I have found that an ordinary table saw with fine tooth wood blade will cut acrylic fine – as long as you move slowly and carefully and avoid excess material clogging the blade. The same goes for drilling holes in acrylic using a drill press – slow and careful will usually work just fine, although the cost of an acrylic-specific drill bit is inexpensive enough to purchase.

Lay the top piece on a flat surface, and align each of the leg pieces so that they are resting on top, flush along the side edge with the 3 holes lined up. Carefully run a single bead of acrylic solvent along the inside joint and let set for a few minutes.

Place each foot piece on the iRobot Create using the four small screw holes. Align the pieces so the wider edges are facing inward and forward. Keep the bolts loose so the foot pieces can be adjusted.

Place the table on the feet with the angled edge of the legs facing forward. Make adjustments to the feet so their edges line up flush with the legs. Carefully run a bead of solvent down each of these joints and let set.


*Optional. Remove the table from the iRobot Create and lay it face down again on a flat surface so the underside is exposed. Use solvent to carefully attach the ½” cubes to each leg/top joint to act as additional structural support.

Once the shelf is ready mount it to the iRobot Create chassis using the four included 10/32 screws. Be sure to place angle brackets mounted in the rear holes under the foot of the shelf, as well as 2 washers in the front holes to maintain an even level. These brackets are used to mount the outer shell to the iRobot.



Outer Shell:

The pattern for Sparky’s outer shell can be downloaded at SparkyJr.com. It is a life-size 2D drawing made in Google SketchUp. It measures 35” x 24 ¼” and can be printed using 15 sheets of paper.

Follow these steps to insure that the pattern prints at exactly 1:1 scale.

1) Download and install SketchUp for your computer.
2) Download and open the file called Sparky_outer_shell_01 from SparkyJr.com.
3) Open the file and switch to paraline mode by turning perspective mode off. To turn perspective mode off, open the "Camera" menu and click "Perspective" (so that a check mark is not displayed next to it).
4) Select a standard scalable view: Top. To select a standard view, open the "Camera" menu, point to "Standard," and then click one of the views.

5 Resize the SketchUp window so the right and left edges of the drawing touch both side edges of the canvas exactly.

6) Open the "File" menu, and then click "Document Setup."
7) In the "Print Size" section of the "Print" dialog box, clear the "Fit to page" option.
8) If you are in paraline mode (step 1) and have selected a standard view (step 2), the scale options in the "Print Scale" section are enabled when you clear the "Fit to page" option. Set the scale to 1” to 1”.
9) Click "OK" to save your document settings, and then print your model by opening the "File" menu, and then clicking "Print."
10) Assemble the pattern using clear tape, taking care to maintain proper alignment.

The pattern was designed with the exact components from the hardware list above - If you are using any different parts, you will need to customize the pattern to fit them. Also, some of the attachment points between the iRobot and the plastic shell are hard to determine with accuracy - it helps to do it bit-by-bit. Assume the first attempt will be a bit of a mess by the time it’s all assembled, so it’s 3not a bad idea to have a few extra pieces of plastic handy.

Layout and tape together the printout of the pattern. Trace it to the material (or cut the paper pattern out and draw around it if you can’t trace it) and cut the pattern out, including the holes for the monitor and speakers and webcam. Drill all the boltholes with a 10/32” drill bit or slightly larger. Allow the cat to help as needed.



Lay the monitor facedown on the plastic, align and hot-glue four small corner brackets to it. Be sure to orient the monitor so the connectors and jacks are on the top edge. Also line up the webcam and hot-glue it along the top edge of the monitor as well. Now you can confirm the alignment of the webcam and mounting holes. Cut and drill these holes and bolt the monitor/webcam to it with the hardware.

Center the speakers over their holes and attach them by running a bead of hot-glue around the edge of each.


Now partially assemble the shell with the 10/32 hardware. Take care to layer the pieces in the proper order or else the holes won’t line up properly. You will notice how the shape becomes structurally rigid with just a few bolts added.

The two holes marked along the bottom front edge of the plastic correspond with two holes drilled through the front bumper of the iRobot Create. Using the holes on the plastic as a guide to mark the bumper, mark and drill the bumper holes.


With the two bumper holes done, and the front edge of the plastic attached to the iRobot Create, check the alignment of the remaining four angle bracket points (one sits on each side of the bumper, and one more sits on each side of the main chassis). Ideally these brackets are aligned so that they have one edge and screw hole flush with the plastic shell. You will need to hot-glue these to the chassis, but take care that they don’t shift in the process.


One of the benefits of hot-glue for this project: It is super strong bonding the angle brackets to the iRobot chassis, but can be pried off with ease and no scarring for re-alignment.

Notice how the front bumper of the iRobot Create still has full range of motion even with the outer shell attached. In fact, the shell is acting like a bumper spring, keeping it in the “out” position and helping it spring back when bumped. If yours is not working, check the alignment of the attachment points and make adjustments as needed.

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