ArcAid, Interactive Archery Assistant

Transcription

1 ArcAid, Interactive Archery Assistant Jente Ameye Dept. of Industrial System & Product Design Ghent University Marksesteenweg 58 Kortrijk, Belgium Sievert van Esch Dept. of Industrial System & Product Design Ghent University Marksesteenweg 58 Kortrijk, Belgium Jeroen Vervaeke Dept. of Electronics and ICT Ghent University. Graaf Karel de Goedelaan 5, Kortrijk, Belgium Abstract This paper reports the concept of an interactive bow aiming application, supported by a smartphone app and the design process that was needed to develop it. Author Keywords Mechatronics; archery; bow; aid; guide; laser; spike; distance; measurement; application; smartphone; flex; interaction ACM Classification Keywords H.5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous [3]. Introduction For the course Mechatronic Design, we had to design an application for a specific sensor. We choose to work with the Spike sensor by Ike [1]. This is a high-end laser sensor for distance measurement. In combination with an app for smartphones that provides the angle of inclination also surfaces can be measured and so on. After exploring different applications for the sensor, we came up with an interactive bow aiming system. Copyright is held by the author/owner(s). ID 4, Sep 21 Jan 28, , Kortrijk, Belgium

2 Figure1.ArcAide Application on smartphone Figure2. Spike by Ike, distance measurement When looking to archery, the sport isn t as accessible for beginners as for professionals. The aiming is complicated and requires a lot of experience, especially for long range goals. With our interactive laser-assisted bow aiming application, we want to support beginner Robin Hoods in their mission to hit the bull s eye. We also hope to get more children playing outside by lowering the startup barriers. The name ArcAid is a combination of Arc - archery, Aid and Arcade. As the name says, the system helps you to aim your bow in an arcade like way. Concept ArcAid is an interactive aiming system for bows. You can attach and connect your smartphone to the system and load the specially designed application to get it started [Figure 1]. The application uses information gathered from the angle of the bow, the Spike module sensor information for the distance to and height of the target [Figure 2]. But also keeps constant traction of the tension on the string of the bow to calculate the trajectory of the arrow. A flow of constant information changing throughout time will then be send to the smartphone showcasing the feedback to the user in a fun and interactive way. By using this information given on the smartphone the user can now adjust the drawback on the bow string or angle of the bow that is given to be able to hit the target. How does it work We divide the workflow into 3 main groups. Locking on target. Calculating trajectory Sending constant feedback Locking on target The Spike sensor has the capability to measure the distance to a single point in space right in front of the infra-red camera. Using this information together with the information of the location of the sensor in space (using the data from the accelerometer in the phone) we can define the distance and height of the target point in comparison to the current location of the sensor. This point in space (together with its location information) can then be locked by pressing the bull s eye on the smartphone screen. Calculating trajectory After the location of the target in space is defined, a constant calculation [4] of the trajectory of the arrow being able to hit the target takes place. In this calculation there are two variables that have the ability to change, being the drawback force on the bowstring and the angle of the bow (angle of arrow departure). So the microprocessor which handles these calculations is constantly recalculating the trajectory of the arrow in the current situation. Sending constant feedback The microprocessor then constantly sends a feedback signal to the smartphone which displays both the needed drawback on the bowstring at the current angle the bow is held at, for the arrow to hit the target. And the needed angle the bow needs to be held at, at the

3 Figure 3. Disassembled Startech II bow. current drawback on the bowstring for the arrow to be able to hit the target. How to use The concept can be divided in different steps: attaching ArcAid system to the bow connecting smartphone start-up Spike and ArcAid application aim your target fine-tune your launch hit the bull s eye The target can be selected easily by using the viewer on the smartphone that shows the distance until the object. When bull s eye is set onto the object, the user can save the target by confirming on the smartphone with a touch on the screen [figure 5]. Now we let the microprocessor compute the needed force and angle to hit it right in the spot. Fine-tuning your launch happens in an interactive game-wise way by making the color bars match in the green spot. This should be your perfect shot to hit the bull s eye. For the prototype we worked with a specific type of bow [Figure 3] [2]. Nice thing about the bow is that you can disassemble it quickly. Hereby the holder can also be detached in an easy way. Figure 4. Connection to smartphone To attach the holder, you have to shove it over the grip until it fits into place and assemble the rest of the bow. Figure5. Locking target Afterwards the smartphone has to be attached onto the holder and connected to the build-in microprocessor using a USB-cable [figure 4]. Next step is starting-up the software, activating the Spike sensor and loading the app on the smartphone [figure 1]. Now you re ready to aim! Figure 6. Aiming with the bow Sensors As said the Spike sensor. Is a high-end laser distance measurement sensor, developed by Ike [Figure 7]. A New-Zealand based company specialized in geoapplications as well as tracking and measuring locations. The most remarkable - in comparison to other laser distance sensors - is its long range and accuracy of the

4 Spike sensor. This sensor can measure an object up to 650 feet (200 m) away with an accuracy of ± 3%. Due to this long range and high accuracy, the sensor is also quite expensive. Processing The incoming flex sensor values, accelerometer and Spike data are processed in the Arduino Nano microprocessor [Figure 9]. Out of kinematic equations and practical tests, we have developed formulas [4] to calculate the force on and inclination of the bow to hit your selected target as close as possible. By fine-tuning this equation we were able to calculate the launch variables being the force on the string and angle of departure so that we could hit the target within a 10cm radius when the arrow is launched from 8m away. Figure 8. Flex sensor permanently attached to bow arc Figure 9. Arduino Nano microprocessor. Figure 7. Picture of the Spike module, attached to a smartphone case. The microprocessor returns the calculated data to the smartphone, where the application shows it in an interactive way to the user in order to achieve hitting the bull s eye. The sensor communicates with your smartphone using Bluetooth 4.0 technology which is available on the most recent smartphones. Next to the Spike sensor for distance measurement, the build-in accelerometer of the smartphone is used do define the angle of inclination. To measure the force on the arrow and the displacement of the string, a flex sensor is attached upon one of the arc of the bow [figure 8]. Interaction A specially designed application delivers interaction with the user. The bull s eye is displayed, together with to bars in arcade style [Figure 10.]. They visualize the angle of the bow and the force on the string. Both bars and the bull s eye on the smartphone are divided in color zones to give the user visual feedback of where the arrow will probably hit. As with other (arcade) games you have to try to get everything into the green zone when launching for a perfect shot.

5 Conclusion With this bow aiming system, we provide a mechatronic design that shows the possibilities of technological applications for interactive use. With the use of our product concept we want to introduce a way for beginner Robin Hoods to learn the art of archery to its fullest. We do this by giving them a fun and interactive learning process that gives constant feedback on how to hit a certain goal. Figure 10. Screenshot of the ArcAid smartphone application. Design Next to the software part of the assignment, a physical object was needed to attach all the hardware. A good looking detachable holder was designed [Figure 12], where the form follows the function. Other things we had to think of where the implementation of the microprocessor and connections onto it. De case we made is a detachable case which slides onto the bow s handle when disassembled and fits into place giving it a sturdy position to hold [Figure 11]. Future plans There are still a few improvements to make, considering this version of the system. It doesn t take the wind into account; therefore we should integrate a wind speed and direction meter. The sensor has the capabilities to be used in professional bows, because it can locate a single target up to 200m. The holder we use now is made for the specific type of bow we used for this project, a learning bow for beginners. This could be redesigned to fit most other bows as well. Figure 11. Dissasembleable elektrical connection Figure 12. Detachable holder

6 Acknowledgements We want to thank all our teachers for the support during the project, especially Mr. Steven, our mentor for this specific case. The design process for this project can be found on the website below in the references [5]. References [1] Spike, ike GPS. [2] Startech II, Geologic by Decathlon. [3] How to Classify Works Using ACM s Computing Classification System. [4] Hibbeler, R.C.H Engineering Mechanics Dynamics. Prentice Hall PTR. [5] ArcAid, Ameye Jente, Vervaeke Jeroen, Van Esch Sievert.