There are ~30 Knowledge Base Articles (KBAs) in the Sensors section of the forum covering multiple sensors products. Sometimes, it's difficult to search for the information that you're interested in, especially when you don't know if that exists or not.
To simplify this task we have created a Sensors Knowledge Base Article List which has all the KBAs divided into sub-topics. This list only contains KBAs which are meaningful today, so you won't find anything related to legacy products. This is to avoid confusing our customers into reading material which is no longer applicable.
We are using an Si7057 in our device to measure the temperature. However we observed an offset between 0.2 and 0.4 degrees compared to older devices in the same environment. The temperature range observed is between 25 and 40 degrees and the offset seems to remain fairly constant. We observed the offset in 30 sensors so far. We are looking for an explanation, but we could not find any.
We checked the decoding of the temperature code, but we could not find an error. We use the following C code to compute the temperature:
Unless I am mistaken, our implementation conforms almost exactly to the specification in the data sheet. Is this implementation correct?
Could this in any way be explained by measurement errors/device variability of the sensors themselves? +.3 degrees would be just within the specification, but for calibrated sensors we expected a somewhat more random distribution across devices and values roughly centered around 0.
However when I try to force measurements from the Si1133 every 1 second, even 3 seconds, the ALS stops updating its latest data after 20-30 seconds. I found out that the program hangs while waiting for REG_IRQ_STATUS register to signal that the channel measurements are completed; specifically line 838:
/* Check if the measurement finished, if not then wait */
retval += read_register(REG_IRQ_STATUS, &response);
while ( response != 0x0F ) {
wait_ms(5);
retval += read_register(REG_IRQ_STATUS, &response);
}
Is this because I am forcing a measurement too quick? When I force measurements every 10 seconds the REG_IRQ_STATUS register does change after the measurement is finished and the program takes longer to hang but it still does eventually. How fast can we poll for a measurement? Our applications requires us to make an ALS reading every 1-2 seconds. How can we go about this? Is there a work around for this? Thanks in advance for your help!
/***************************************************************************//**
* @file
* @brief Relative humidity and temperature sensor demo for SLSTK3402A
*******************************************************************************
* # License
* <b>Copyright 2018 Silicon Laboratories Inc. www.silabs.com</b>
*******************************************************************************
*
* The licensor of this software is Silicon Laboratories Inc. Your use of this
* software is governed by the terms of Silicon Labs Master Software License
* Agreement (MSLA) available at
* www.silabs.com/about-us/legal/master-software-license-agreement. This
* software is distributed to you in Source Code format and is governed by the
* sections of the MSLA applicable to Source Code.
*
******************************************************************************/
#include "em_device.h"
#include "em_chip.h"
#include "em_cmu.h"
#include "em_emu.h"
#include "em_gpio.h"
#include "cpt112s_config.h"
#include "i2cspm.h"
#include "si7013.h"
#include "sl_sleeptimer.h"
#include "graphics.h"
#include "em_adc.h"
#include "bspconfig.h"
/***************************************************************************//**
* Local defines
******************************************************************************/
/** Time (in ms) between periodic updates of the measurements. */
#define MEASUREMENT_INTERVAL_MS 2000
/***************************************************************************//**
* Local variables
******************************************************************************/
/* Variables used by the display callback. */
static void (*mem_lcd_callback_func)(void*) = 0;
static void *mem_lcd_callback_arg = 0;
/** This flag tracks if we need to update the display
* (animations or measurements). */
static volatile bool updateDisplay = true;
/** This flag tracks if we need to perform a new
* measurement. */
static volatile bool updateMeasurement = true;
/** This flag indicates that a new measurement shall be done. */
static volatile bool measurement_flag = true;
/** Timer used for periodic update of the measurements. */
static sl_sleeptimer_timer_handle_t measurement_timer;
/** Timer used for periodic maintenance of the display. */
static sl_sleeptimer_timer_handle_t display_timer;
/***************************************************************************//**
* @brief Setup GPIO, enable sensor isolation switch
*****************************************************************************/
static void gpioSetup(void)
{
/* Enable GPIO clock */
CMU_ClockEnable(cmuClock_GPIO, true);
/* Enable Si7021 sensor isolation switch */
GPIO_PinModeSet(CS0_SENSOR_EN_PORT, CS0_SENSOR_EN_PIN, gpioModePushPull, 1);
}
/***************************************************************************//**
* @brief Helper function to perform data measurements.
******************************************************************************/
static void measure_humidity_and_temperature(I2C_TypeDef *i2c, uint32_t *rhData, int32_t *tData)
{
Si7013_MeasureRHAndTemp(i2c, SI7021_ADDR, rhData, tData);
}
/***************************************************************************//**
* @brief Callback from timer
******************************************************************************/
static void measurement_callback(sl_sleeptimer_timer_handle_t *handle, void *data)
{
(void)handle;
(void)data;
measurement_flag = true;
}
/***************************************************************************//**
* @brief Main function
******************************************************************************/
int main(void)
{
I2CSPM_Init_TypeDef i2cInit = I2CSPM_INIT_DEFAULT;
EMU_DCDCInit_TypeDef dcdcInit = EMU_DCDCINIT_STK_DEFAULT;
CMU_HFXOInit_TypeDef hfxoInit = CMU_HFXOINIT_DEFAULT;
uint32_t rhData = 0;
bool si7013_status;
int32_t tempData = 0;
/* Chip errata */
CHIP_Init();
/* Initalize hardware */
EMU_DCDCInit(&dcdcInit);
CMU_HFXOInit(&hfxoInit);
/* Switch HFCLK to HFXO and disable HFRCO */
CMU_ClockSelectSet(cmuClock_HF, cmuSelect_HFXO);
CMU_OscillatorEnable(cmuOsc_HFRCO, false, false);
/* Use LFXO for rtcc used by the sleeptimer */
CMU_ClockSelectSet(cmuClock_LFE, cmuSelect_LFXO);
CMU_ClockEnable(cmuClock_HFLE, true);
/* Initalize other peripherals and drivers */
gpioSetup();
sl_sleeptimer_init();
GRAPHICS_Init();
I2CSPM_Init(&i2cInit);
/* Get initial sensor status */
si7013_status = Si7013_Detect(i2cInit.port, SI7021_ADDR, 0);
GRAPHICS_ShowStatus(si7013_status);
sl_sleeptimer_delay_millisecond(2000);
/* Set up periodic measurement timer */
sl_sleeptimer_start_periodic_timer_ms(&measurement_timer, MEASUREMENT_INTERVAL_MS, measurement_callback, NULL, 0, 0);
EMU_EnterEM2(false);
while (true) {
if (measurement_flag) {
measure_humidity_and_temperature(i2cInit.port, &rhData, &tempData);
measurement_flag = false;
GRAPHICS_Draw(tempData, rhData);
}
EMU_EnterEM2(false);
}
}
/***************************************************************************//**
* @brief The actual callback for Memory LCD toggling
******************************************************************************/
static void display_callback(sl_sleeptimer_timer_handle_t *handle, void *data)
{
(void)handle;
(void)data;
mem_lcd_callback_func(mem_lcd_callback_arg);
}
/***************************************************************************//**
* @brief Register a callback function at the given frequency.
*
* @param[in] pFunction Pointer to function that should be called at the
* given frequency.
* @param[in] argument Argument to be given to the function.
* @param[in] frequency Frequency at which to call function at.
*
* @return Always return 0
******************************************************************************/
int rtccIntCallbackRegister(void (*pFunction)(void*),
void* argument,
unsigned int frequency)
{
mem_lcd_callback_func = pFunction;
mem_lcd_callback_arg = argument;
uint32_t ticks = sl_sleeptimer_get_timer_frequency() / frequency;
sl_sleeptimer_start_periodic_timer(&display_timer, ticks, display_callback, NULL, 0, 0);
return 0;
}
My application is: detect day versus night, indoors, in a room with south facing windows. I am exploring the Si1133 to measure UVA. I can put the detector within 10 feet of the windows, high and facing down so the detector gets reflected UV, and never gets direct sunlight, and gets only reflected artificial lights from typical room lighting of about 400 lux white, fluorescent light. My understanding is the window glass will transmit about 50% of UVA, that the sky will scatter significant UVA, that night sky has no UVA, and that artificial lights produce negligible UVA.
Might that work? Do you have any suggestions re diffuser, physical filters, parameters of the Si1133, and which set of diodes to use? My plan is to read only the UV diode.
I want to estimate sun time by detecting sundown and sunset, despite noise from artificial lights. I don't need accuracy. I plan to take samples over many days. I understand that the weather and season will have an effect.
We are designing a Si7210 sensor into a product and have some questions about it. In the Si7210 datasheet the typical RMS Noise is listed as 30 uT at 25C, 5V and 20 mT range. In App note AN1018 scaling of the noise with supply voltage is provided (5V/Vdd). I have some questions about the noise:
How does the noise change when operating at the 200 mT range?
How does the noise change with temperature?
Is there any guidance on worst case (maximum) noise?
Can someone show me the spectral responce of the UV sensor? In the data sheet *) (version 0.91) section 3.2 UV index sensing:
"The UV Index is a number linearly https://trackeasy.fun/usps/ related to the intensity of sunlight reaching the earth and is weighted according to the CIE erythemaAction Spectrum"That is a general explanation about UV-index
I'm special interested in the responce in the range of UV-A and UV-B 290-400 nm.
To whom it may concern, the datasheet does not include any information concerning the RoHS Compliancy for the Si7021-A20-GM1R so it can't be used as proof of RoHS Compliancy. We are using this part in one of our products and need a RoHS Certificate or some form of documentation stating RoHS Compliancy for our document control. I need this as soon as possible. It is holding up the release of a product. Thank you, Roger
I have an SI1147-M01-EB evaluation kit. I have downloaded the SI114x Programmers Toolkit, but I cannot get a connection to the hardware. The quick-start guide refers to Windows 7 only, so is it impossible to make this kit work on a Windows 10 machine?
In Device Manager, the device appears as an HID (Human Interface Device) rather than under Ports or USB - is this the problem?
If I launch SI1140 Control Panel, under devices I can see COM1 or TS004A572A. Pressing Connect with either device selected results in an error - unable to set baud rate for COM1 and unable to initialize SI114x. Function: InitSI114x for TS004A572A.
Also, when I launch the Firmware Updater, what should I choose from the evaluation board drop-down? Module?
I am working with Si7021 I2C HUMIDITY AND TEMPERATURE SENSOR. I have few questions about this sensor.
1. I am not able to get an acknowledgement from the sensor for start signal sent by the controller. Please provide a sample c code for interfacing with Atmega microcontroller.
2. The SDA and SCL lines should be pulled up t0 3.3V or 5V?
3. Is it possible to change the address of the sensor and have two such sensors on the same I2C line?
4. At what frequency should the communication between the controller and sensor take place?
5. How much time does the sensor take on an average to get new temperature/humidity reading?
We are using a Si1133 chip on a board with a STM32L4 MCU. We have ported the code available at https://siliconlabs.github.io/Gecko_SDK_Doc/efm32pg12/html/si1133_8c_source.html, and we are able to measure the lux and UVI (still not tested for accuracy). We want to be able to configure the Si1133 to generate an interrupt if there is a sudden light level change (increase), is it possible this kind of application using this chip? My doubt is because if we enable the IRQ we will be interrupted on each light measurement end, we are not able to configure it to interrupt the CPU only when the threshold level is exceeded, or am I missing some alternative configuration? To be able to detect autonomously a sudden high light level it should be running in autonomous mode, so it will interrupt the MCU at the end of each measurement cycle, right?
When I use the routine, after turning on high power consumption and two lights, the bin file size is 79 KB
Is this size normal? Can I reduce the bin file size.
In addition， SI117xHRM_HRM_DATA_SIZE，SI117xHRM_HRM_MULTI_LED_DATA_SIZE and SI117xHRM_RR_INTERVAL_DATA_SIZE in "si117xhrm.h",Can these definitions of sample size be reduced？
What impedance will the LED pins have when the circuit is powered down?
More precise, if Si115x is powered from an regulated power domain (which could be turned off) while the IR-LED is powered directly from the battery.omeglexender
What happens with the LED input on the Si115x if the power supply to the circuit is shut of when the IR-LED still is powered from the battery.
Is there a risk for current leakage through the LED that eventually could drain the battery, if so how large would that leakage be.
Or is the design of the current sink regulator done so that a high impedance is guaranteed?
In this situation is it recommended to have the pull-up resistors connected to the regulated power domain which Si115x is powered from or is there any reason to have the resistors connected directly to the battery together vid the LED?
I have an analog temperature sensor (TMP36GSZ-REEL-see datasheet here) and it is properly connected to an analog pin for reading its output.
The Arduino sketch (firmware) works just fine. Everything actually works fine except for two things:
If I plug more components in the circuit, like for example connecting an LED in parallel, temp readings go up for 1 degree (Celsius).
From time to time the readings go crazy (like 80°C or 100°C), although it's never that hot in here.
The connection is like this: from the Arduino's 5V pin to the sensor positive lead. Then, from the sensor's negative lead to the GND pin in Arduino. And finally, from the middle lead to the A1 analog reading pin.
Why are situations 1 and 2 happening? Is this normal?
Forum
Sensors Knowledge Base Article List
There are ~30 Knowledge Base Articles (KBAs) in the Sensors section of the forum covering multiple sensors products. Sometimes, it's difficult to search for the information that you're interested in, especially when you don't know if that exists or not.
To simplify this task we have created a Sensors Knowledge Base Article List which has all the KBAs divided into sub-topics. This list only contains KBAs which are meaningful today, so you won't find anything related to legacy products. This is to avoid confusing our customers into reading material which is no longer applicable.
Additionally please check out our Sensors training page -> https://www.silabs.com/support/training/sensors
Si7057 temperature offset?
We are using an Si7057 in our device to measure the temperature. However we observed an offset between 0.2 and 0.4 degrees compared to older devices in the same environment. The temperature range observed is between 25 and 40 degrees and the offset seems to remain fairly constant. We observed the offset in 30 sensors so far. We are looking for an explanation, but we could not find any.
We checked the decoding of the temperature code, but we could not find an error. We use the following C code to compute the temperature:
float SI705Y_CalcTemp(uint16_t tc)
{
return 175.0 * (float)tc / 65536.0 - 45.0;
}
Unless I am mistaken, our implementation conforms almost exactly to the specification in the data sheet. Is this implementation correct?
Could this in any way be explained by measurement errors/device variability of the sensors themselves? +.3 degrees would be just within the specification, but for calibrated sensors we expected a somewhat more random distribution across devices and values roughly centered around 0.
Si1133 - How fast can I force a measurement for an ALS reading?
Hi there,
I managed to get the Si1133 to work with the example code found here https://os.mbed.com/teams/SiliconLabs/code/Si1133/rev/
However when I try to force measurements from the Si1133 every 1 second, even 3 seconds, the ALS stops updating its latest data after 20-30 seconds. I found out that the program hangs while waiting for REG_IRQ_STATUS register to signal that the channel measurements are completed; specifically line 838:
/* Check if the measurement finished, if not then wait */ retval += read_register(REG_IRQ_STATUS, &response); while ( response != 0x0F ) { wait_ms(5); retval += read_register(REG_IRQ_STATUS, &response); }Is this because I am forcing a measurement too quick? When I force measurements every 10 seconds the REG_IRQ_STATUS register does change after the measurement is finished and the program takes longer to hang but it still does eventually. How fast can we poll for a measurement? Our applications requires us to make an ALS reading every 1-2 seconds. How can we go about this? Is there a work around for this? Thanks in advance for your help!
si7021deacreasing sampling time bellow 1ms
Thanks.
Si1133 How to detect daylight indoors in south facing room while ignoring artificial lights, using UV.
My application is: detect day versus night, indoors, in a room with south facing windows. I am exploring the Si1133 to measure UVA. I can put the detector within 10 feet of the windows, high and facing down so the detector gets reflected UV, and never gets direct sunlight, and gets only reflected artificial lights from typical room lighting of about 400 lux white, fluorescent light. My understanding is the window glass will transmit about 50% of UVA, that the sky will scatter significant UVA, that night sky has no UVA, and that artificial lights produce negligible UVA.
Might that work? Do you have any suggestions re diffuser, physical filters, parameters of the Si1133, and which set of diodes to use? My plan is to read only the UV diode.
I want to estimate sun time by detecting sundown and sunset, despite noise from artificial lights. I don't need accuracy. I plan to take samples over many days. I understand that the weather and season will have an effect.
Si7210 Hall Effect Sensor Noise
We are designing a Si7210 sensor into a product and have some questions about it. In the Si7210 datasheet the typical RMS Noise is listed as 30 uT at 25C, 5V and 20 mT range. In App note AN1018 scaling of the noise with supply voltage is provided (5V/Vdd). I have some questions about the noise:
Thanks.
Si1133 spectral responce in UV-range?
Can someone show me the spectral responce of the UV sensor? In the data sheet *) (version 0.91) section 3.2 UV index sensing:
"The UV Index is a number linearly https://trackeasy.fun/usps/ related to the intensity of sunlight reaching the earth and is weighted according to the CIE erythemaAction Spectrum"That is a general explanation about UV-index
I'm special interested in the responce in the range of UV-A and UV-B 290-400 nm.
With kind regards
Need RoHS Certificate or Some Form of RoHS Compliancy Document for Si7021-A20-GM1R
SI1147-M01-EB with Windows 10
Hi,
I have an SI1147-M01-EB evaluation kit. I have downloaded the SI114x Programmers Toolkit, but I cannot get a connection to the hardware. The quick-start guide refers to Windows 7 only, so is it impossible to make this kit work on a Windows 10 machine?
In Device Manager, the device appears as an HID (Human Interface Device) rather than under Ports or USB - is this the problem?
If I launch SI1140 Control Panel, under devices I can see COM1 or TS004A572A. Pressing Connect with either device selected results in an error - unable to set baud rate for COM1 and unable to initialize SI114x. Function: InitSI114x for TS004A572A.
Also, when I launch the Firmware Updater, what should I choose from the evaluation board drop-down? Module?
Can someone help please?
Thanks
Si7021 sample C code to interface with 8bit Atmega microcontroller.
I am working with Si7021 I2C HUMIDITY AND TEMPERATURE SENSOR. I have few questions about this sensor.
1. I am not able to get an acknowledgement from the sensor for start signal sent by the controller. Please provide a sample c code for interfacing with Atmega microcontroller.
2. The SDA and SCL lines should be pulled up t0 3.3V or 5V?
3. Is it possible to change the address of the sensor and have two such sensors on the same I2C line?
4. At what frequency should the communication between the controller and sensor take place?
5. How much time does the sensor take on an average to get new temperature/humidity reading?
Si1133 - how to configure an interrupt on a sudden light change
Hi,
We are using a Si1133 chip on a board with a STM32L4 MCU. We have ported the code available at https://siliconlabs.github.io/Gecko_SDK_Doc/efm32pg12/html/si1133_8c_source.html, and we are able to measure the lux and UVI (still not tested for accuracy). We want to be able to configure the Si1133 to generate an interrupt if there is a sudden light level change (increase), is it possible this kind of application using this chip? My doubt is because if we enable the IRQ we will be interrupted on each light measurement end, we are not able to configure it to interrupt the CPU only when the threshold level is exceeded, or am I missing some alternative configuration? To be able to detect autonomously a sudden high light level it should be running in autonomous mode, so it will interrupt the MCU at the end of each measurement cycle, right?
Thanks in advance
Best regards
Fernando
Si117x efmpg1 bin file size problem
When I use the routine, after turning on high power consumption and two lights, the bin file size is 79 KB
Is this size normal? Can I reduce the bin file size.
In addition， SI117xHRM_HRM_DATA_SIZE，SI117xHRM_HRM_MULTI_LED_DATA_SIZE and SI117xHRM_RR_INTERVAL_DATA_SIZE in "si117xhrm.h",Can these definitions of sample size be reduced？
Wrist based heart rate - pulse oximetry solution from Silabs??
Hello,
Is there any wrist-based (reflective) solution from Silabs for heart rate/pulse oximetry monitoring?
In particular, does Silabs offer:
- Analog front end (AFE) for reflective HR/SpO2 sensing, preferably with integrated optics (Leds/PDs)?Speed Test essay writer
- If optics are not integrated recommendation for 3rd party optical components to use
- Validated algorithm (FDA grade?) to derive Heart Rate and Saturation levels from the PPG signal acquired by the AFE?
- Evaluation kit to evaluate the performance of the suggested solution
Many thanks in advance for any advice
Si115x behavior at power down?
What impedance will the LED pins have when the circuit is powered down?
More precise, if Si115x is powered from an regulated power domain (which could be turned off) while the IR-LED is powered directly from the battery.omegle xender
What happens with the LED input on the Si115x if the power supply to the circuit is shut of when the IR-LED still is powered from the battery.
Is there a risk for current leakage through the LED that eventually could drain the battery, if so how large would that leakage be.
Or is the design of the current sink regulator done so that a high impedance is guaranteed?
In this situation is it recommended to have the pull-up resistors connected to the regulated power domain which Si115x is powered from or is there any reason to have the resistors connected directly to the battery together vid the LED?
Best Regard
Why is my analog temp sensor's signal so unstable?
I have an analog temperature sensor (TMP36GSZ-REEL-see datasheet here) and it is properly connected to an analog pin for reading its output.
The Arduino sketch (firmware) works just fine. Everything actually works fine except for two things:
If I plug more components in the circuit, like for example connecting an LED in parallel, temp readings go up for 1 degree (Celsius).
From time to time the readings go crazy (like 80°C or 100°C), although it's never that hot in here.
The connection is like this: from the Arduino's 5V pin to the sensor positive lead. Then, from the sensor's negative lead to the GND pin in Arduino. And finally, from the middle lead to the A1 analog reading pin.
Why are situations 1 and 2 happening? Is this normal?