From BTD2011

Contents 1 Group 1 members 1.1 Project Features 2 The Bicycle Safty Kit 2.1 Description 2.2 Android App 2.3 Technical realisation 2.3.1 Material 2.3.2 Prototype 2.4 Final Version 2.5 Evaluation 2.5.1 Interview 2.5.2 Results 2.6 Project Video

[edit] Group 1 members

• Oliver Hödl
• Tobias Grimus
• Matthias Tretter
• Taner Yagmur

[edit] Project Features

• combine Android phone with wearable sensors
• track the velocity during biking
• adjust the brightness of lamps on front and back that are attached to a cloth according to velocity
• wearable belt/helmet/clothes with sensors
• map the route via GPS on the Android phone
• detect crashes and perform an emergency action
• warn the driver with vibrator sensor if he exceeds a velocity limit

[edit] The Bicycle Safty Kit

The goal of the Bicycle Safety Kit is to increase the safety of the driver as well as the safety of the passerbys that are crossing the driver’s way. There are already some papers covering the topic of biking, most of them concentrating on improving motivation and gathering statistics during biking [2]. Safety issues on riding bicycles are very important and new technologies have been used intensively to develop and improve safety for riding bicycles.
Ming-Yi Dai et al. have presented “A Safety System for Intelligent Portable Hybrid Electric Bicycle” [1] that includes an anti-crash warning system and a balanced tire pressure monitoring system. One big disadvantage of this system is that it is attached to the bicycle. You can only use it with this bike and when it gets stolen all technology is gone as well.

[edit] Description

The Bicycle Safety Kit wants to improve safety during biking by increasing awareness of the driver’s speed. This is achieved by combining various sensors together measuring the current state of the driver. We decided on using the Amarino Toolkit [3] which can provide a connection between an Android Smartphone and an Arduino Microcontroller via Bluetooth.
The features of the Bicycle Safety Kit are:

• Crash Detection with optional emergency action
• Increasing speed awareness of the driver
• Increasing speed awareness of passerbys
• Statistical map showing speed peaks at different locations for increasing the awareness of the speed after a ride.

The heart of our safety system is an App for the Android Mobile Phone System. By using the built-in GPS-Sensor it measures the current speed of the driver and draws a map that indicates potential dangerous speed levels at given points. By activating a vibrator sensor when the user exceeds a pre-defined speed limit we warn the driver and therefore increase his awareness of his speed.
By using data from the mobile phones Accelerometer as well as the gyroscope and the speed information derived from GPS we can detect crashes with very high probability. In case of such a crash the phone automatically performs a pre-defined emergency action (e.g. an automated call, sms, post to twitter with current location, …).
Furthermore the App communicates with a LillyPad Microcontroller and adjusts the brightness and color of LEDs attached to the bikers clothes. Increased speed results in brighter lights, warning the passerbys of the speed of the driver.
The advantage of our system is the flexibility:

• Parts of the crash-detection system are integrated in the mobile phone
• The wearable safety belt is part of the biker’s clothes
• The core-application runs on a smart-phone, so there are only few additional costs for the hardware

[edit] Android App

File:1 Android.jpg

The Android App can be used as a standalone App without connection to the Lillypad. A connected Lillypad of course enhances the experience by providing more feedback (vibration and lights). The main features of the App are:

1. Utilizing the built-in GPS sensor for gathering location data
2. showing a waiting-dialog until a pre-defined GPS accuracy is reached and then starting the tracking
3. deriving speed information from the GPS data
4. creating a route of the GPS coordinates
5. coping with memory and performance issues, when gathering lots of GPS-data
6. drawing the route on top of a Google Map
7. color-coding the speed into the route-overlay, starting with green (=slow) by gradually going to yellow (=normal) and red (=fast)
8. user-definable settings (speed limits, Arduino bluetooth address)
9. debug-mode that allows to send test-data to the Arduino
10. communication with the Arduino over bluetooth (sending speed, signals for starting/stopping vibration)
11. vibration of the mobile phone in combination with the vibration of the vibrator motor attached to the Arduino

The App was developed in an object-oriented fashion using a class-hierarchy, several development patterns (e.g. Observer-Pattern), abstraction and so on, resulting in a total of

16 classes and 1716 lines of code.

The biggest technical issues we had to face with the Android Application was getting reasonable data from the GPS sensors. Mobile phone GPS sensors are very inaccurate, it takes some time to get an initial fix and the latency is very big. Another hard thing was color-coding the map overlay in a attrictive fashion and at the exact points the GPS fix was measured. The third biggest part was the communication with the Arduino via Bluetooth. It took us a long time to get the first valid communication between the Android App and the Arduino.

The source code is open and can be found on Google Code: Bicycle Safety Kit

[edit] Technical realisation

[edit] Material

Parts needed for the Bicycle Safety Kit:

• Lots of LEDs (white and red)
• LillyPad with bluetooth module
• Battery kit for LillyPad
• Android Mobile Phone with GPS Sensor, Accelerometer and (optionally Gyroscope)
• A vibrator to warn the user if he is very fast
• “conductive cotton”
• optional: external accelerometer/gyroscope for saftety belt (minimizing error rate of built-in sensors of mobile phone)
• an adjustable belt that can be worn around the body either horizontal or from the shoulder to the hip.

[edit] Prototype

Tutorial / Experiment Bluetooth connection between Laptop and Arduino (16.04.2011): based on [1]

1. Code via USB to LilyPad
2. Remove USB-Cable from LilyPad
3. Connect Bluetooth Mate to LilyPad. Power supply with Arduino Duemilanove („+“ and „Gnd“)
4. Add BT device on laptop
5. Key „1234“
6. Set serial port in Arduino GUI (Tools->serial Port) to COM 13 (=BT outgoing)
7. BT connection (green light on module) will be active if serial monitor is opened
8. If serial monitor is closed, BT is disconnected. Reconnection is possible after restart of Arduino GUI (bug)

Pictures: File:Prototype1

Lilypad for our Safety-Kit what we have: 14 outputs for LEDs and Vibrator
6 inputs for external gyroscope and accelerator that means:
1 output for vibrators on wristband
1 output for blinking led on wristband right
1 output for blinking led on wristband left
11 outputs for different LEDS on jacket

Results
1 vibrator with variable interval for vibrating on/off (digital pin 2)
2 orange leds with variable blinking speed and three combinations (left, right or both blinking) (digital pin 3-4)
5 bright leds blinking from left to right with variable speed (digital pin 5-9)

[edit] Final Version

The final prototype consists of the vest with five LEDs on the back, a wire connection to the front left side where a pocket has been applied to store the Lilypad and the battery.

CIMG5165

Furthermore there is a vibrator wired to the Lilypad to warn the driver when he exceeds the specified speed limits. The vibrator is placed on a velcro strip that is to be applied to the cyclists wrist.

cimg5159, CIMG5160

In our approach we favoured functionality over aesthetics, while preserving the ability to use the device on every bike without having to attach devices to the bike.
We decided to use the vest instead of a helmet because hardware such as the LEDs and the Lilypad are more easily attached to the vest.

[edit] Evaluation

[edit] Interview

Gender:
Age:

1. How often did you use your bike weekly?
2. Which bike do you use? (e.g. own, city-bike, friend’s bike)
3. If your own bike, how long do you have it?
4. Has your bike been stolen in the past? How often during which period of time?
5. How much money would you pay for a new bike? (for normal bike and for “top-safety-bike”)
6. Which things do you wear while riding? (e.g. backpack, helmet)
7. What are you doing for safety during biking?
8. Which additional things would you wear/carry if they increase safety?
9. Where do you carry your phone?
10. Would you wear a safety belt and wristband?
11. Would you wear a safety jacket?
12. Would you wear a helmet?

[edit] Results

• Bicycle drivers have a low tendency to wear safety equipment

• Participants of the interview don't want to spend money on safety.

• Wearing a backpack might obstruct the view of the LED circle on the back of the vest.

[edit] Project Video

Bicycle Safety Kit on Youtube

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