Wireless ABS system

1. Wireless ABS system By: Srej Balázs Pereira Raymond Alejandro Escalada Arto Toppinen Anssi Suhonen Savonia Polytechnic

2. Frame of the presentation • Aimand Problems • Main parts andideas • Central quad (data collector) • Sensor and dynamo part (peripherals) • Possible Solutions: • Energy storage • Communication protocol • Security encryption • Summary

3. Aim and problems: • Main idea is to work out an absolutely wireless ABS sensor system • 1st stage of problems: • How to ensure power supply without wires? • Realize a safety RF communication between the peripheries and central data collector. • Create interface between the central computer of the car and the central quad.

4. Task and problems: • 2nd stage of problems: • Stopped car: there is no Dynamo effect, no power supply (battery usage  price, size) • There are 4 wheels, necessary to use 4 RF receiver device (safety reasons). • Transmission loss tolerance is very less for this system.

5. Central Quad (transceiver) • Wireless data collector interface • Main function of it, is to receive the RF signals from the peripheral devices Reproduce the signal and transmit directly to the central computer in the car. • It Contains four RF signal receiver chip

6. Sensor and dynamo part • Wireless sensor interface The dynamo should be light weighted but efficient enough to provide power supply for the sensor and the RF interface In order to implement the wireless system, we can use the same old sensors with the dynamo and the RF interface added to it.

7. Possible solutions Energy storage: • For the case when a car is stopped necessary to supply the sensor circuits by battery • At least necessary to use a capacitor which can provide enough energy until the CPU is going to send a break (roll-back lock) message and goes to sleep mode.

8. Message ID/ TYPE 12bit Add-on signals 4bit +/- Deviation Message ID/ TYPE 12bit Possible solutions Communication protocol: The RF communication will solve with Chipcon cc2510 RF microcontrollers. Max data rate: 500kbps Normal payload: in every 250ms Alarm payload: in all critical event

9. Possible solutions Security encryption: • In the used RF device, there is a encryption / decryption coprocessor. It gives opportunity to protect the RF messages. The encryption could be done at maximum 128 bit. • Necessary to use encryption to make safer the communication.

10. Duty cycle of data transmission • Transmission when the car is in motion and working normally. • Transmission in the emergency situation of breaking. 1 250 500 750 t (ms) 2 250 250 500 500 750 750 t (ms) Emergency signals

11. Data Packet Format

12. Representation of the System Dynamo and wireless sensor interfaces Central data collector interface Customized Protocol

13. System Realization Wired set-up is replaced by the RF parts

14. Schematics of the simulator

15. Available options: • Accelerometer to measure the efficiency of suspension • Temperature sensor • Pressure sensor to measure the break fluid pressure

16. Summary • Aims of the project: To develop a cost effective wireless ABS system, in which the sensor data will be transmitted to the central circuit wirelessly. Also, to make the system really wireless the power supply to the peripheral circuits is derived from the local dynamos. • Expected results: The cost of the entire system should be less than or equal to 8€. We expect the system to function as reliably as the original wired system