Wemos LOLIN32: Unterschied zwischen den Versionen
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The [https://wiki.wemos.cc/products:lolin32:lolin32 Wemos LOLIN32 ] is a | The [https://wiki.wemos.cc/products:lolin32:lolin32 Wemos LOLIN32 ] is a [http://espressif.com/sites/default/files/documentation/esp-wroom-32_datasheet_en.pdf ESP-WROOM-32] based IoT development board. | ||
It is available in the [https://hacker.parts]. | |||
As the original page has no documentation at all, here are some findings about the hardware. | As the original page has no documentation at all, here are some findings about the hardware. | ||
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esptool.py --port /dev/ttyUSB0 erase_flash | esptool.py --port /dev/ttyUSB0 erase_flash | ||
esptool.py --port /dev/ttyUSB0 write_flash -z 0x1000 esp32-20180108-v1.9.3-238-g42c4dd09.bin # Adjust image Name | esptool.py --port /dev/ttyUSB0 write_flash -z 0x1000 esp32-20180108-v1.9.3-238-g42c4dd09.bin # Adjust image Name | ||
== Upload Files == | |||
You can use [https://github.com/adafruit/ampy ampy] to upload files. | |||
WebREPL should also work, but it looks like this code is also missing in the current ESP32 branch of Micropython. | |||
ampy is very straight forward.: | |||
ampy --port /dev/ttyUSB0 put main.py | |||
== I2C == | == I2C == | ||
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i2c.scan() | i2c.scan() | ||
== | == Battery Monitoring == | ||
Unfortunately, no direct method of battery voltage measurement is built into the system. | |||
But it should be quite easy to implement such a thing: Use a voltage divider on the battery to get a 1.1V max. For a 4.2V cell, this can be achieved using a 27k and 100k resistor. | |||
Note, that the ADC of the ESP32 is set to 1.1V range by default! You can use the attenuation but this is not available on every platform. | |||
^ V_bat | |||
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R1 = 100k | |||
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+----o ADC | |||
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R2 = 27k | |||
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GND | |||
Now you can measure the voltage on the battery using the ADC. As the ADC is 12bit, you can get the actual voltage by multiplying the reading by ((27+100)/27) * 1.1 / 2**12, or in more general terms: ((R1 + R2) * V_ref) / (R2 * 2**Resolution). | |||
Super nice would be charge monitoring. The TL4054 can do this, you need to hookup to the PRG pin. But this results in nasty bodges on the SOT23 chip... | |||
== Battery == | |||
The battery can be connected via a JST PH2 connector. | |||
They can be bought also from Conrad: [https://www.conrad.at/de/buchsengehaeuse-kabel-phr-polzahl-gesamt-2-jst-phr-2-rastermass-2-mm-1-st-740547.html ArtNr. 740547]. | |||
== Example Projects == | |||
* Temperature and Humidity measurement using collectd as datalogger: [https://github.com/reox/esp32_sht21_collectd ESP32_SHT21_collectd] | |||
== Further Readings == | |||
* [http://esp32.net/ esp32.net] | |||
[[Kategorie:English]] | |||
[[Kategorie:Interessensgebiete]] | |||