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https://github.com/sensirion/arduino-liquid-flow-snippets

Arduino Code Snippets for Raw Sensor Communication with Sensirion Liquid Flow Sensors
https://github.com/sensirion/arduino-liquid-flow-snippets

arduino flow-meter ld20 liquid-flow-sensor lpg10 ls32 sensirion

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Arduino Code Snippets for Raw Sensor Communication with Sensirion Liquid Flow Sensors

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README 

        
# Sample Code for Arduino



## Summary

The Arduino Platform allows for easy prototyping with endless possibilities. In

order to enable our customers to use this platform, we provide sample code for

use with Sensiron AG's liquid flow sensors. This application note describes the

examples, as well as the main code components used in the examples. It is meant

as a starting point for setting up communication with the liquid flow sensors

through the I2C interface.



## Compatibility

The code snippets are generally compatible with Sensirion's digital flow

sensor portfolio. The current portfolio is based on two different sensor chips,

the SF04 and the SF06.

More specifically:

### SF04

SLG, SLI, SLS, SLQ-QTxxx, LG16-xxxxD, LS32 and LPG10 series sensors.

### SF06

LD20 and SLF3x series sensors.



## Introduction

This sample code library is aimed at customers who have successfully set up

their Arduino and connected their Sensirion liquid flow sensor. Please see the

[Arduino Quick Start Guide](https://web.archive.org/web/20220816230009/https://developer.sensirion.com/archive/tutorials/arduino-interface-for-liquid-flow-sensors/)

for help in setting up your Arduino and liquid flow sensor.

Sensirion provides code examples showcasing the most important use cases of I2C

communication with our liquid flow sensors.



## Code Examples

### SF04

|Folder | Number & Name                  | Description                                  |

|-------|--------------------------------|----------------------------------------------|

|SF04   | 01 Simple Measurement          | Reads simple measurement data from the
sensor. |

|SF04   | 02 Set Resolution              | Reads measurement data from the sensor and
changes the resolution. |

|SF04   | 03 Read Scale Factor and Unit  | Reads the scale factor and measurement unit
information from the sensor's EEPROM. |

|SF04   | 04 Read Product Details        | Reads the product details (serial number and product name). |

|SF04   | 05 CRC Checksum                | Reads flow measurement data from the sensor
and calculates the checksum of the
communication for error detection. |

|SF04   | 10 Calibration Field           | Describes the necessary steps to change the
calibration field settings. |

|SF04   | 11 Read Temperature Voltage    | Demonstrates how to read temperature and
voltage data. |

|SF04   | 12 Two's Complement            | Demonstrates how to use the signed datatype
interpretation directly and how to calculate
the two's complement manually. |

|SF04   | 13 DIY Flow Meter              | Expands on example 3 to build a stand-alone
flow meter using a graphic LCD. |



### SF06

|Folder | Number & Name                 | Description                                  |

|-------|-------------------------------|----------------------------------------------|

|SF06   | 14 Simple measurement (LD20-2600B) | Reads simple measurement data from the
LD20-2600B. |

|SF06   | 15 Simple measurement (SLF3S-1300F) | Reads simple measurement data from the
SLF3S-1300F and highlights where
changes have to be made for other SF06
sensors. |

|SF06   | 16 CANBUS receive | Demonstrates how to forward measurement data over CANBUS.
This is useful for some test setups. |

|SF06   | 17 CANBUS send | Demonstrates how to forward measurement data over CANBUS.
This is useful for some test setups. |

|SF06   | 18 DIY closed loop volume controller | Demonstrates how an SLF3x can be used
together with a pump to dispense a controlled volume. |

|SF06   | 19 DIY flow meter | Stand-alone flow meter using a praphic LCD (SF06 sensors). |

|SF06   | 20 simple measurement multiple SLF3x | Demonstrates how to use an I2C multiplexer
(TCA9548A) to communicate with up to 8
SLF3x sensors on the same bus.  |



## Prerequisites

In order to initiate the serial communication, `Serial.begin(9600)` should be

used to set the baud rate to 9600. The code examples require the use of the

"Wire"-library. This Arduino library contains all the relevant functions for

the communication between your Arduino and the I2C device. The provided code

examples are all based on this library and typically use the following

functions:



| Functions                             | Description

|---------------------------------------|--------------------------------------|

| Wire.begin()                          | Join I2C bus (address optional for
master). |

| Wire.beginTransmission(ADDRESS)       | Initiate a transmission transaction 
with the device at ADDRESS
over I2C. |

| Wire.write(value)                     | Queues bytes for transmission from
master to slave. |

| Wire.endTransmission()                | Commit the transmission transaction:
start, send data, stop. |

| Wire.requestFrom(ADDRESS, LEN)        | Master requests data (LEN bytes)
from slave at ADDRESS and
store to buffer. |

| Wire.available()                      | Retrieve the length of the I2C buffer. |

| Wire.read()                           | Read data from the I2C buffer.       |



For further details, please refer to Arduino's official

[Wire Documentation](https://www.arduino.cc/en/Reference/Wire).



## SF04 Sensor Commands

The following table shows the commands that are typically used for I2C

communication. The commands need to be transmitted through the

`Wire.write(Value)` function that is part of Arduino's Wire library for I2C

communication.



| Command                   | Value | Description           | See Example(s)   |

|---------------------------|-------|-------------------------------|----------|

| USER\_REG\_W              | 0xE2  | Write user register           | 10, 11   |

| USER\_REG\_R              | 0xE3  | Read user register            | 10, 11   |

| ADV\_USER\_REG\_W         | 0xE4  | Write advanced user register  | 2        |

| ADV\_USER\_REG\_R         | 0xE5  | Read advanced user register   | 2        |

| READ\_ONLY\_REG2\_R       | 0xE9  | Read-only register 2          | 4        |

| TRIGGER\_FLOW\_MEASUREMENT| 0xF1  | Trigger a flow measurement    | 1-13     |

| TRIGGER\_TEMP\_MEASUREMENT| 0xF3  | Trigger a temperature measurement | 11   |

| TRIGGER\_VDD\_MEASUREMENT | 0xF5  | Trigger a supply voltage measurement | 11|

| EEPROM\_R                 | 0xFA  | Read EEPROM                   | 3, 4, 13 |

| SOFT\_RESET               | 0xFE  | Soft reset                    | 1-13     |



## SF06 Sensor Commands

SF06 based sensors have a simplified I2C interface. The measurement commands are

calibration specific and therefore depend on the respective sensor. The

available commands are listed in the sensors' datasheets.



## Two's Complement

The two's complement is a binary number representation. This notation is widely

used in computer science to represent both positive and negative integer

numbers. To get the two's complement notation of a negative integer, first write

the absolute value of that integer in binary representation b = bin(abs(x)).

Then invert the binary bit sequence b (i.e. change every 1 into a 0 and every 0

into a 1). Finally, increment the number represented by b by one.

Note that all negative numbers will thus carry a 1 in their highest bit.



**Example: Represent -5 in 8bit**



1. binary representation of absolute value: b = bin(abs(-5)) -> 0000 0101

2. invert: b = xor(b, 1111 1111) -> 1111 1010

3. Increment by one: b = b + 1 -> 1111 1011