Offline Tracker Device concept.
| RF Options | Frequency | Data | Distance | |
|---|---|---|---|---|
| Lora | **** | 915/868 Mhz | 4 | 4 |
| nRF24L01 | *** | 2.4 Ghz | 4 | 4 |
| RF | *** | 433 Mhz | 1 | 5 |
| BLE | ** | 2.4 Ghz | 4 | 1 - 2 |
| WiFi | * | 2.4 Ghz | 4 | 1 - 2 |
| Distance Measurement | Challenge | |||
|---|---|---|---|---|
| Signal Power | Low reliability | |||
| Ping Time | Based on the time it took to send and receive a data back. | |||
| Triangulation | Multiple trackers must. | |||
| GPS | Expensive, high power consumption |
| Direction Determination | Challenge | |||
|---|---|---|---|---|
| Multi Frequencies | Most likely expensive, interference might be an issue. | |||
| Antenna Array | Calculation required. High clock speed might be required = Power | |||
| Triangulation | Might give rough estimation. | |||
| Ultrasonic Sound | Ultrasonic audio, requires multiple microphones, works in close distance (which is fine) | |||
| Other Comments | ||||
|---|---|---|---|---|
| 1 | UI | Screen isn't a must simple LED is fine, can be turned on while tracking. | ||
| 2 | Mesh | Mesh might be a good idea, neighboring devices would increase reliability, although means more power. | ||
| 3 | Mesh | Mesh can be done in 2 ways, just relaying anything or like a router might keep neighboring device list with ids. | ||
| 4 | DIY | Parts should be easy to get for common Joe | ||
| 5 | Existing Tech | There is a project called meshtastic, exiting network might be utilized in favor. | ||
| 6 | Power | Tracking devices should be able to run at least a week. | ||
| 7 | Portability | Tracker device, shouldn't be heavy to carry around. Desired form factor is something in between Walkie Talkie / Cellphone to smart watch. |
| Device Identification | ||||
|---|---|---|---|---|
| 1 | Trackers should have an ID, how to assign these id's are challenge. | |||
| 2 | Main device can be paired and can be assigned through. | |||
| 3 | Main device might have a bluetooth or wifi, for configuring through a phone. | |||
| 4 | Impersonation might be an issue. Something like a mac adress could be useful. | |||
| Expansion | ||||
|---|---|---|---|---|
| I have another idea for emergency communication protocol, might be merged with that. | ||||
| Emco | ||||