https://github.com/peterhinch/micropython-radio

Simple way to use an nRF24L01 radio to exchange arbitrary Python objects between two Pyboards
https://github.com/peterhinch/micropython-radio

embedded micropython nrf24l01 protocol radio

Last synced: 3 months ago
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Simple way to use an nRF24L01 radio to exchange arbitrary Python objects between two Pyboards

• Host: GitHub
• URL: https://github.com/peterhinch/micropython-radio
• Owner: peterhinch
• License: mit
• Created: 2016-01-13T09:28:16.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2022-12-26T15:29:42.000Z (almost 2 years ago)
• Last Synced: 2024-04-22T12:33:28.699Z (7 months ago)
• Topics: embedded, micropython, nrf24l01, protocol, radio
• Language: Python
• Size: 81.1 KB
• Stars: 52
• Watchers: 6
• Forks: 11
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-mpython - micropython-radio - Protocols for nRF24L01 2.4Ghz radio modules. (精选驱动库 / 通讯类)
• awesome-micropython - micropython-radio - Protocols for nRF24L01 2.4GHz radio modules. (Libraries / Communications)

README

        
# micropython-radio

This repo comprises two protocols for the nRF24L01+ radio module. Each

implements a bidirectional link between two radios.

## radio-fast

A driver for short fixed-length records. This is a thin layer over the official

driver which makes it easier to ensure mutually compatible configurations of

the radios. This is done by deploying a common config file to both nodes.

The nRF24L01 provides data integrity but successful reception is not guaranteed

as radio outages can occur (see below).

In this protocol one radio acts as master (initiating communications) and the

other acts as slave (responding to transmissions)

See [README](./radio-fast/README.md)

## as_nrf_stream.py

See [README](./async/README.md)

Radio links are inherently unreliable, not least since receiver and transmitter

may move out of range. The link may also be disrupted by radio frequency

interference. This driver mitigates this by ensuring that, in the event of a

link outage, data transfer resumes without loss when connectivity is restored.

The use of `uasyncio V3` stream I/O means that the interface matches that of

objects such as sockets and UARTs. Objects exchanged are `bytes` instances,

typically terminated by a newline character (`b'\n'`). Lengths of the `bytes`

objects are arbitrary and are allowed to vary at runtime. Consequently it is

easy to exchange Python objects via serialisation libraries such as `pickle`

and `ujson`.

The underlying protocol's API hides the following details:

 1. The radio hardware is half-duplex (it cannot simultaneously transmit and

 receive).

 2. The chip has a 32 byte limit on message length.

 3. To address point 1 the protocol is asymmetrical with a master/slave design

 which is transparent to the user.

The driver provides a symmetrical full-duplex interface in which either node

can initiate a transmission at any time. The cost relative to the `radio-fast`

module is some loss in maximum throughput and an increase in latency. Gains

are:

 * The ability to exchange relatively large, dynamic objects.

 * Data integrity with each message being correctly received exactly once.

 * A standard bidirectional (full duplex) stream interface.

 * Asynchronous code: in the event of an outage communication will inevitably

 stall for the duration, but other coroutines will continue to run.

## Obsolete modules

The `as_nrf_stream` driver replaces the old `radio-pickle` and

`async-radio-pickle` modules which pre-dated the `uasyncio` I/O interface. This

module is simpler, smaller and more efficient. Lastly the old asynchronous

driver allowed duplicate messages to be received. The new protocol ensures that

each record is received exactly once.