Tablets and all-in-one PCs featuring a touchscreen-enabled display are convenient and fun to work with. But a touchscreen monitor isn’t quite affordable for most just yet. Using a Wii remote (Wiimote) from Nintendo’s gaming console, you can make your regular monitor (LCD or CRT) behave as a basic touch panel. Given below is a simple workshop to convert almost any given surface (be it your LCD monitor, table surface or a whiteboard (or wall) along with a projector) into a touch-enabled surface. All you would need is a Wiimote, a simple utility from the internet, a Bluetooth dongle and an infrared light source. This whole workshop has been inspired by Johnny Lee from his website ‘http://johnnylee.net’.
The Nintendo Wiimote can be purchased separately
What you would need for this project:
- A Nintendo Wiimote: You can use your existing console’s remote or buy one from eBay for about Rs. 1,000. You might also consider borrowing one from a friend to test this out first.
- A Bluetooth USB dongle: Unless your laptop or desktop features built-in Bluetooth, you can pick up one of these for as little as Rs. 120.
- An IR LED: This item can be bought from your local electronics store or can be ripped from any old or non-working IR remote controller you might have laying around.
- A push or touch switch: This switch can be ripped from an old PC case (the reset switch) or any non-working gadget which has a push switch for example the volume control, power, reset button etc.
- A ball-point pen: Preferably a basic plastic-based pen - drilling holes, making cuts or using super glue is easier on plastic.
- Some really thin wires: Any wire slim enough to pass through the pen’s housing should suffice.
- Mercury batteries (button-sized): You can either use a regular motherboard CMOS battery (3.2 V) or three watch cells (1.2 V each). Ideally, you require around 3 volts – 4.5 volts to power up the IR LED of the IR pen. The tiniest batteries would be ideal as they can be easily housed inside the cap at the rear end of the pen.
- Battery holder: The holder would depend on the battery type. In our case, we ripped out the CMOS battery and holder from a dead motherboard.
- Tools: This would involve standard tools such as knife, soldering iron, solder wire, super glue, electricians tape, etc.
- WiimoteWhiteboard utility: This utility can be downloaded for free from here. The utility is used for calibrating the Wiimote for the touchscreen and for the entire working of this project.
Let’s get started -
The IR pen:
First, you will need to make yourself an IR (infrared) pen. This pen is nothing more than an IR LED powered by a few batteries and controlled by a push/touch switch to switch it on or off. The IR pen is required because the Wiimote has a built-in IR camera which needs an IR light source for detecting various points for operation.
We made this IR pen using a basic plastic pen and mounted the battery and holder from an old dead motherboard
Building the IR pen is pretty simple will take just a few minutes. All you need is to figure out a way to mount the IR LED onto the tip of the pen and power it using a battery and mount the switch. To build one, here are a few simple steps -
Remove and discard the refill from the pen—we need just the housing. The part where the refill’s nib exits the housing is where the IR LED needs to be mounted. Cut, slice or do whatever is needed to get the LED to fit snugly onto pen’s housing, but remember that the whole LED should be visible on the exterior. If the LED is blocked or covered by the pen’s housing, the IR light will not be visible for the Wiimote to function. Once you have figured out how the LED can be mounted, your next step is to mount the switch and the battery. Finally, solder the wires to the switch, battery holder and the IR LED and run the wires through the pen. Glue everything in place after testing the pen.
Since IR light is invisible, you can test it by pointing the IR LED towards any available camera (video camera, digital camera, mobile camera or webcam), pressing a button and you should see the LED glow via the viewfinder.
Have a look at the diagram for the wiring idea and a picture of the IR pen we made. Now that the IR pen is ready, you have completed 80 percent of the workshop. All you need now is to connect the Wiimote to the PC, download a simple utility and calibrate the Wiimote with your screen.
The circuitry for the IR Pen is shown here. If you are not confident with soldering, we suggest you take help from a friend
Connecting the Wiimote to the PC:
In order to connect the Wiimote to the PC, turn on the Wiimote and the Bluetooth hardware on your PC/laptop and pair the device with your system. On the Wiimote, press the red ‘Sync’ button located inside the battery compartment. The Wiimote will then show up on your Bluetooth utility as a game controller. Pair the two without any pass code and then let the OS install the necessary drivers on its own.
The Wiimote will then show up on your Bluetooth utility as a game controller. Select to pair the two without any pass code. Let the operating system install the necessary drivers on its own.
Placement of the Wiimote is very crucial for this workshop. The Wiimote should always be in the line-of-sight of the IR pen. So the Wiimote should be facing the screen at all times. Basically, for the Wiimote to identify the whole surface to be used as a touchscreen, a 90-degree angle (the Wiimote facing directly to the screen) is the best option. But since this is not possible as while using the pen you would tend to get in between the IR pen and the Wiimote camera. This will block the view for the Wiimote, inhibiting proper functioning. So you can place the Wiimote at an angle of 45-degrees on the left or the top of the screen area. This angle is the best position if you are a right-handed person. To place the Wiimote on the left or top of the screen, you can use a tripod stand and use a few rubber bands to secure it in place or simply place it at a proper angle on a sturdy surface. We have made a custom stand using an old webcam’s mount assembly.
You can place the Wiimote depending on your comfort and usage. Use the monitor as a touchscreen or use a table, whiteboard or a wall as a touch surface.
Note: Once you have placed the Wiimote in a particular position you should not move it at all. If you do, you will need to recalibrate the Wiimote all over again.
Calibrating the Wiimote:
In order to get the setup working, you need to download the simple utility which basically is the Wiimote driver and calibration tool. Once your Wiimote is paired with your PC and placed at the required angle, run the ‘WiimoteWhiteboard’ utility. If the pairing of the Wiimote is functional, the utility will run and a window with some information about the Wiimote battery status and tracking utilization will be visible.
Options for cursor control (to enable or disable the Wiimote cursor), a cursor smoothing slider (to smoothen the cursor movement on the screen) and a calibration button will also be available. The next step is to click on the ‘Calibrate Location (Wiimote A)’ button to start the calibration process. You can also start the calibration by pressing the ‘A’ button on the Wiimote at this point or at any time when using the IR pen to recalibrate the points. We don’t recommend using the button in the Wiimote as this tends to move the Wiimote from its position.
Using the utility, place the Wiimote appropriately and then calibrate it precisely
After clicking the button, the screen will turn white and you will notice a circle with a cross on the left corner. This circle is the beginning of the calibration process. Using the IR pen, touch the circle on the screen and press the button (only once) on the pen. The IR LED will illuminate and send a signal to the Wiimote to detect the top left corner of the screen. If the detection is successful, you will see the circle disappear and then move to the top right corner. Continue with the same method till you finish all four corners.
Note: if you accidentally click twice, the circles will jump across and your touchscreen will not be calibrated properly. If this happens, rerun the calibration process. After the calibration is done, the white screen will disappear. Now you can minimize the calibration utility and use your monitor as a touchscreen.
Use an old webcam mount to make a stand
The button on the IR pen will act as the left-click of the mouse. The mouse cursor will not be visible during this time. A little practice will help you learn the entire usability of the system. You can place the Wiimote at different angles (at times even lower than the 45-degree angle) to suit the best possible position according to your preference. The angle completely depends upon the screen area which should be visible to the Wiimote at all times. A too steep angle can cause calibration errors.
Since you will be using the IR pen on the surface of the LCD monitor, there are possibilities of scratching the surface of the LCD panel. We recommend putting a screen guard over the display. Since a screen guard is very expensive, you can also use the initial screen protector (plastic sheet) that came with monitor packaging. Other options are to use a transparency sheet large enough to cover the screen area.
This workshop is best applicable for whiteboard presentations and handwriting inputs wherever necessary. The utility is still under development and will improve in time.
Published Date: Oct 07, 2011 05:20 pm | Updated Date: Oct 07, 2011 05:20 pm