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https://github.com/timhanewich/loralink
A fully 3D-printed remote controller that uses Long Range (LoRa) radio communications to control an RC car.
https://github.com/timhanewich/loralink
controller lora micropython pico raspberry-pi rc-car rpi-pico rylr998 wireless
Last synced: about 2 months ago
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A fully 3D-printed remote controller that uses Long Range (LoRa) radio communications to control an RC car.
- Host: GitHub
- URL: https://github.com/timhanewich/loralink
- Owner: TimHanewich
- License: mit
- Created: 2024-08-13T19:51:10.000Z (4 months ago)
- Default Branch: master
- Last Pushed: 2024-09-26T21:46:31.000Z (3 months ago)
- Last Synced: 2024-10-11T22:22:07.611Z (2 months ago)
- Topics: controller, lora, micropython, pico, raspberry-pi, rc-car, rpi-pico, rylr998, wireless
- Language: Python
- Homepage:
- Size: 93.8 KB
- Stars: 1
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- Changelog: changelog.md
- License: license.md
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README
# LoRaLink RC Remote Controller
A fully 3D-printed remote controller that uses Long Range (LoRa) radio communications to control an RC car.
## Onboard Components
LoRaLink has quite a few physical components that serve various functions, including control input, communication, GUI display, etc.:
- 1 [SSD-1306 OLED display](https://a.co/d/6dm97JF) (128x64)
- 3 [16MM Push Buttons](https://a.co/d/9F2s5Ny)
- 2 [B10K Potentiometers](https://a.co/d/18x64NA) (knobs)
- 1 [Toggle Power Switch](https://a.co/d/8mkSPU3)
- 1 Raspberry Pi Pico
- 1 [REYAX RYLR998 LoRa Module](https://a.co/d/5QcWzvi)
- 1 [MT3608 Boost Converter](https://a.co/d/7Znw4Il)
- 1 18650 Lithium-Ion battery
- 1 [TP4056 Charge Controller](https://a.co/d/eq3EDgR)
In addition to the components above, you'll also need:
- 4 M2 screws (about 8 mm in length will work)
- 1 long M2 screw (16-18mm?) for screwing in the 18650 battery holder to the bottom
- Some 22-gauge wire (or whatever gauge you have/prefer)
- A 47K Ohm resistor
- A 100K Ohm resistor
- A lot of solder!
## Wiring
The wiring diagram for the LoRaLink controller is included below. However, you can open [the schematic file](./schematic.drawio) on [draw.io](https://draw.io) as well (may be a bit easier to read).
## Assembly
I've provided the STL files for this design that you can 3D-print yourself [on Thingiverse here](https://www.thingiverse.com/thing:6729642). Altogether, there are three parts you'll need to print:
- **bottom.stl** - The "box" of the controller, that each electronic component will go into.
- **bottom_v2.stl** - Raspberry Pi Pico USB is now accessible from the side. TP4056 moved over a bit to make room.
- **bottom_v3.stl** - 20mm taller (to better accomodate electronics).
- **top.stl** - The top plate of the controller that the power switch, SSD-1306, potentiometers, and buttons will be mounted to.
- **18650_frame.stl** - A frame to hold the 18650 battery. Wrap wires around both ends to touch each terminal. Screw this into the bottom.stl.
## Changelog
For a full changelog, view the [changelog.md file](./changelog.md).
## Communication Protocol
I've designed a minimalistic, lightweight, robust communication protocol to allow communications between the LoRaLink controller and the device that it is being controller.
All encoding/decoding of these packets into their binary representation is handled by the [bincomms.py](./src/bincomms.py) module, but I further describe the communication protocol below.
The LoRaLink controller and the device being controlled will use a pre-established protocol for communicating with each message being stored as a *packet*. There for **four** packet types:
- Packet Type **0** = Operational Command
- Packet Type **1** = Operational Response
- Packet Type **2** = Pulse Call
- Packet Type **3** = Pulse Echo
These packets are further described below:
### The "Pulse Call" Packet
When the LoRaLink controller boots up, it first aims to establish communication with the controlled device via a "pulse" check. The LoRaLink controller sends out this packet to the device and then awaits a response, confirming the presence of the controlled device.
The **Pulse Call** packet is only a single byte:
### The "Pulse Echo" Packet
When the controlled device (likely an RC car) boots up, it continuously listens for the **Pulse Call** packet above. Once it receives it, it confirms its presence by responding with the **Pulse Echo** packet, only a single byte:
### The "Operational Command" Packet
Once communicatation is established via the Pulse Call/Echo packets above, The LoRaLink controller then begins continuously sending a stream of control commands to the controlled device using the **Operational Command** packet, consisting of two bytes, and described below:
A value of **1** in the *Throttle Direction* bit means the throttle is positive (forward) while a value of **0** means the throttle is negative (reversing). The same applies to the steering: **0** is a left turn, **1** is a right turn, for the *Steering Direction* bit.
The throttle value and steering value are encoded as 6-bit values as seen above.
### The "Operational Response" Packet
Occasionally, during normal operation, the controlled device will send this packet back to the controller as a "I'm still alive" message, but also to inform it of its battery level (which will be displayed on the LoRaLink controller).
As seen above, the remaining 6 bits not used as a packet identifier are used to carry data about the battery.
## Other Misc. Resources
- The PowerPoint deck I used to create the visuals above that depict the binary communication protocol can be downloaded [here](https://github.com/TimHanewich/LoRaLink/releases/download/1/comm_protocol.pptx).