possibility to create htu with existing i2c object #1
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does not block when waiting for data
htu21d.py
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| Args: | ||
| write_address (int): address to write to | ||
| :return: | ||
| """ | ||
| import time |
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an import does not belong here.
htu21d.py
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| self.i2c.start() | ||
| self.i2c.writeto_mem(int(self.ADDRESS), int(write_address), '') | ||
| self.i2c.stop() | ||
| data = bytearray(3) | ||
| time.sleep_ms(50) |
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im not really sure if this is needed. i did not need it at all. Will see if readfrom_into is a blocking request.
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according to the datasheet (https://cdn-shop.adafruit.com/datasheets/1899_HTU21D.pdf) you should wait at least 50ms before reading the result. All arduino libraries do the same.
Can't remember if I added this because I had problems, but I probably did.
htu21d_async.py
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| from machine import I2C, Pin | ||
| import uasyncio as asyncio | ||
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| class HTU21D(object): |
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why do you copy the complete class instead of inherit it?
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I tested adding async functions to the original library first but my tests showed me that I could save RAM by copying the class and removing the sync functions, so I went for that way.
htu21d_async.py
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| async def humidity_async(self): | ||
| raw = await self._issue_measurement_async(self.ISSUE_HU_ADDRESS) | ||
| if raw is None or raw==0: |
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you could also do a if not raw or is there any specific reason to do not?
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and why is 0 a bad value? 0 is perfectly fine and would give a relative humidity value of -6% which is the minimum of the htu.
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0 theoretically is fine but sometimes I got the raw value 0 which was obviously an error so I tried to add the 0 to the errors.
htu21d_async.py
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| async def temperature_async(self): | ||
| raw= await self._issue_measurement_async(self.ISSUE_TEMP_ADDRESS) |
htu21d_async.py
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| def __init__(self, scl=None, sda=None, i2c=None): | ||
| """Initiate the HUT21D | ||
| Args: |
htu21d_async.py
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| async def _issue_measurement_async(self,write_address): | ||
| while self.running: | ||
| await asyncio.sleep_ms(160) | ||
| self.running=True |
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missing spaces around assignment
htu21d_async.py
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| self.i2c.stop() | ||
| data=bytearray(3) | ||
| except: | ||
| print("Error in HTU instruction") |
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print statements aren't good ideas for error reporting.
I would like to see an exception raised if something happens there instead of a print
and silently ignoring the error and just returning none.
I also would like to see a more explicit exception catch instead of a "catch" all.
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You are right, the print was a leftover from debugging, errors in these parts mostly indicate that the sensor is not connected (or not working correctly). Have to check the exact error to catch it. Did not pay attention to that as I only wanted to add the running = False which is basically a (cheap) lock preventing multiple readings at the same time, as this is possible with async. Or should that lock be removed and one should just handle this in code using the sensor?
htu21d_async.py
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| data=bytearray(3) | ||
| except: | ||
| print("Error in HTU instruction") | ||
| self.running=False |
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missing spaces around assignment
htu21d_async.py
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| self.i2c.readfrom_into(self.ADDRESS, data) | ||
| if not self._crc_check(data): | ||
| raise ValueError() | ||
| raw=(data[0]<<8)+data[1] |
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missing spaces around assignment.
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Btw. im sorry that i forgot to thank you for the very first PR ;P |
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Was using your library in my esp8266 smart home system and modified it for asyncio and wanted to share it back to you. Was my first pull request, so thanks for your detailed answers and especially for the library! Please check the outdated ones too, github got some of those wrong.. they are still in the code, i just added the requested lines and spaces around assignments. |
Adds the possibility to create a htu object with an existing i2c object, so you can create it before and use it afterwards without knowing which devices created the i2c object.
I think this should be possible.
Many libraries just expect an i2c object, so now it is up to the user.
Also the temperature and humidity are functions now. Makes more sense to me especially as I was converting the library to be asynchronous (separate file).
What do you think?
Thanks for your work,