On Fri, Jun 22, 2018 at 6:04 PM, Himanshu Jha <himanshujha199640@xxxxxxxxx> wrote: > Hi Matt, > >> > For now I have placed the sensor in the IMU but this is not an IMU and there >> > is no such sensor(4-in-1) in the whole IIO subsystem. So, where should it >> > be placed ? >> > Would it be worthwhile to create a new subdirectory "environmental" since >> > it is a environmental sensor ? >> > >> >> Since it the most interesting feature is the VOC sensor I'd think it >> would make more sense in drivers/iio/chemical (maybe I'm biased of >> course). > > Yes, the gas sensing part is the most distinguished feature of the > sensor and relatively different from Temperature, Pressure & Humidity. > > But still not sure about the placement. > >> Even thought is doesn't output a processed value that you can use >> without Bosch's software. >> >> Also I've looked briefly at the datasheet, and wondering why this >> can't be added to the existing BMP280 driver (like how the BME280 >> humidity support was added). > > Agreed! I had this same question on my mind but if you look carefully at > the BME280 datasheet "5.2 Register compatibility to BMP280" Pg 24, says > that BME280 & BMP280 share the same register addressing which is why it > was a wise decision to add them in a single driver. You don't need to > make new functions for temp, press, humid, read_calib, chip_config, > etc., separately and rather use a generic function for both of them. > > Also, bme680 has some peculiar characteristics such as: > > 1. different chip id address for SPI and I2C. > 2. Two power modes only and no *normal mode* > > And a few more... > > It is sad that Bosch discusses about the trimming/calibration parameters in > both bmp280 & bme280 but not in my(bme680) case. I don't know why ? > > Although I got to know about it through Bosch BME680 API but since it is > mentioned *not* in datasheet and rather in their API. So, we need their > permission before using it and it's been two weeks since I and Daniel both > sent the email and no reply :( > > Anyway, you're a chemical sensor expert and I have a question for > you which I would really appreciate if you could answer: > > The user needs to supply to attributes to the gas sensor: > > 1. Heater temperature: For eg. 200 degC to heat the sensor > heater elemnent used for sensing. So, this 200 degC is converted > to register code using BME680 API algorithm. > > 2. Heater duration: The duration for which heater will be > heated. For eg. 100ms > > What would be the appropriate channel type for the above ? Just use IIO_TEMP and signal it is an output channel. Of course for the VOC part of it will be IIO_RESISTANCE since it doesn't output a ppm/pbb value. > > Thank you for your time and that "Industrial I/O and You" Conference > video :) > > -- > Himanshu Jha > Undergraduate Student > Department of Electronics & Communication > Guru Tegh Bahadur Institute of Technology -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
