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| -rw-r--r-- | README.md | 10 | ||||
| -rw-r--r-- | si7021d | 73 | ||||
| -rw-r--r-- | systemd/si7021d.service | 10 |
3 files changed, 93 insertions, 0 deletions
diff --git a/README.md b/README.md new file mode 100644 index 0000000..aa463e4 --- /dev/null +++ b/README.md @@ -0,0 +1,10 @@ +# si7021d + +A Linux daemon that reads and returns data from a Si-7021 sensor. Written on Python. + +It starts TCP server, accepts command `read` and returns JSON with sensor readings. +You can send as many `read` commands during one connection as you want. + +## License + +MIT
\ No newline at end of file @@ -0,0 +1,73 @@ +#!/usr/bin/env python3 +import smbus +import argparse +import asyncio +import json +import logging + + +logger = logging.getLogger(__name__) +bus = None +lock = asyncio.Lock() + + +async def si7021_read(): + async with lock: + await asyncio.sleep(0.01) + + # these are still blocking... meh + raw = bus.read_i2c_block_data(0x40, 0xE3, 2) + temp = 175.72 * (raw[0] << 8 | raw[1]) / 65536.0 - 46.85 + + raw = bus.read_i2c_block_data(0x40, 0xE5, 2) + rh = 125.0 * (raw[0] << 8 | raw[1]) / 65536.0 - 6.0 + + return rh, temp + + +async def handle_client(reader, writer): + request = None + while request != 'quit': + try: + request = await reader.read(255) + if request == b'\x04': + break + request = request.decode('utf-8').strip() + except Exception: + break + + if request == 'read': + rh, temp = await si7021_read() + data = dict(humidity=rh, temp=temp) + else: + data = dict(error='invalid request') + + writer.write((json.dumps(data) + '\r\n').encode('utf-8')) + await writer.drain() + + writer.close() + + +async def run_server(host, port): + server = await asyncio.start_server(handle_client, host, port) + async with server: + logger.info('Server started.') + await server.serve_forever() + + +if __name__ == '__main__': + parser = argparse.ArgumentParser() + parser.add_argument('--host', type=str, default='127.0.0.1') + parser.add_argument('--port', type=int, default=8306) + parser.add_argument('--bus', type=int, default=0, + help='Bus number (X for /dev/i2c-X)') + + args = parser.parse_args() + logging.basicConfig(level=logging.INFO) + + bus = smbus.SMBus(args.bus) + + try: + asyncio.run(run_server(args.host, args.port)) + except KeyboardInterrupt: + logging.info('Exiting...') diff --git a/systemd/si7021d.service b/systemd/si7021d.service new file mode 100644 index 0000000..8537ca4 --- /dev/null +++ b/systemd/si7021d.service @@ -0,0 +1,10 @@ +[Unit] +Description=si7021 daemon +After=network-online.target + +[Service] +Restart=on-failure +ExecStart=/usr/local/bin/si7021d --bus 0 --host 0.0.0.0 + +[Install] +WantedBy=multi-user.target |