Vehicle safety system, distance determination method, and vehicle

1. A distance determination method, comprising:

detecting, at a second electronic device, a first received signal strength indicator (RSSI) of a wireless signal sent from a first electronic device;

detecting, at the first electronic device, a second RSSI of a wireless signal sent from the second electronic device;

obtaining, at the first electronic device, the first RSSI from the second electronic device; and

calculating, at the first electronic device, a distance of the second electronic device relative to the first electronic device according to the first RSSI and the second RSSI; and

starting a process of certification between the first electronic device and the second electronic device when the distance continues to decrease.

2. The distance determination method of claim 1 , wherein the calculating comprises:

determining a first distance based on the first RSSI and a first relationship of RSSI and distance;

determining a second distance based on the second RSSI and a second relationship of RSSI and distance;

determining the distance based on the first distance and the second distance.

3. The distance determination method of claim 1 , further comprising:

requesting a random number from the first electronic device by the second electronic device;

providing the random number to the second electronic device by the first electronic device;

providing a temporary key generated based on the random number to the first electronic device by the second electronic device; and

verifying the temporary key with a built-in authentication code pre-stored in the first electronic device by the first electronic device.

4. The distance determination method of claim 1 , wherein one of the first electronic device and the second electronic device is a remote device or an accessory, and another of the first electronic device and the second electronic device is a communication module attached to a vehicle.

5. The distance determination method of claim 4 , further comprising:

automatically locking/unlocking the vehicle based on a certification result and the distance.

6. The distance determination method of claim 4 , further comprising:

establishing a first connection between the remote device the communication module;

establishing a second connection between the remote device the accessory; and

establishing a third connection based on the first connection and the second connection.

7. The distance determination method of claim 6 , further comprising certificating the first connection, wherein the certificating comprises:

requesting a random number from the communication module by the remote device;

providing the random number to the remote device by the communication module;

transferring the random number to a server by the remote device;

creating a temporary key by the server in response to receiving of the random number;

providing the temporary key to the communication module via the remote device by the server; and

verifying the temporary key with a built-in authentication code pre-stored in the communication module by the communication module.

8. The distance determination method of claim 1 , wherein the calculating comprises:

averaging the first RSSI and the second RSSI.

9. The distance determination method of claim 1 , further comprising:

retrieving a first RSSI-distance curve of the first RSSI;

retrieving a second RSSI-distance curve of the second RSSI; and

calculating a third RSSI-distance curve based on the first RSSI-distance curve and the second RSSI-distance curve,

wherein the calculating comprises calculating the distance based on the third RSSI-distance curve.

10. The distance determination method of claim 9 , wherein the calculating the third RSSI-distance curve comprises at least one of:

averaging the first RSSI-distance curve and the second RSSI-distance curve;

calculating the third RSSI-distance curve by resampling the first RSSI-distance curve and the second RSSI-distance curve at different sampling distances; and

calculating the third RSSI-distance curve by iteratively resampling the first RSSI-distance curve and the second RSSI-distance curve as sampling distance changes.

11. A vehicle, comprising:

a frame;

a rear wheel, rotatably connected to the frame and turned by pedaling a pedal;

a hub device installed on the rear wheel for providing auxiliary power to turn the rear wheel and comprising a charging connector and a built-in battery; and

a power delivery charger, detachably connected to the charging connector, including a USB connector for detachably connected to a USB power bank, and configured to deliver power from the USB power bank to the built-in battery via the charging connector for charging the built-in battery and heating the built-in battery during operation.

12. The vehicle of claim 11 , further comprising a bag tied on the frame, wherein the power delivery charger is accommodated in the bag.

13. The vehicle of claim 11 , wherein the vehicle is an electric bicycle.

14. The vehicle of claim 11 , further comprising:

a hard housing connected to the frame and accommodating a circuit board of the power delivery charger; and

a bag hanging on the hard housing, wherein the USB power bank is in the bag.

15. The vehicle of claim 14 , further comprising:

a seat cushion connected to the frame, wherein the hard housing is located under the seat cushion and extends toward the rear of the vehicle above the rear wheel, wherein the hard housing is detachably fastened to the frame.

16. The vehicle of claim 11 , wherein the frame has an opening at a bottom side thereof and is hollow inside, the power delivery charger is accommodated in the frame, and the opening is configured to allow the power delivery charger to pass through.

17. The vehicle of claim 16 , further comprising a sealing member sealing the opening.