Prag JROV 2023 06 27.pdf

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1、Prague,June 26-30,2023#EMBEDDEDOSSUMMITBuild a Pump Monitor for Railway Applications with Zephyr OSOliver Vlckers,BeST Berliner Sensortechnik GmbHovbestsensor.deJonas Remmert,Phytec Messtechnik GmbHj.remmertphytec.deZephyr Project Page:https:/www.zephyrproject.org/portfolio/best-sensor-pump-monitor-

2、jrov2201/Prague,June 26-30,2023#EMBEDDEDOSSUMMITOliver Introduction to Pump Monitor Project(6 slides)Can AI recognize Wastewater Flow?(6 slides)Jonas Overview Firmware(4 slides)Power Management(4 slides)Lessons Learned(3 slides)QuestionsPrague,June 26-30,2023/27BeST Sensor Wastewater Pump Project JR

3、OV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmImprove Deutsche Bahn ICE Train ToiletsToilets in ICE high-speed trains out-of-order.Why?wastewater tank full,because not properly emptied pump failures go unnoticed,too late to fix toiletTask:develop a system that monitors

4、wastewater pump quality automatically and reliably4/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmMobile Monitoring SystemPumps equipped with adapter including sensor systemNo energy supply,no wired connection,no gatewayConnection

5、 via mobile radioBattery-operated system5/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmApplication-Specific SensorConventional flow meters cannot differentiate between empty pipe and blockageWaste water is variable:solid,liquid,g

6、as,mixtures such as foamHybrid sensor:pressure,vibration,temperature,humidity sensors6/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmWhy we use Zephyr RTOSBare-metal programming-too smallFull PC OS like Linux-too bigZephyr RTOS-ri

7、ght sizeMultitasking of peripheralsreal-time operationenergy savingNordic Semiconductor nRF9160 SDK based on ZephyrOpen Source7https:/www.zephyrproject.org/products-running-zephyr/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmResu

8、ltsWe developed a monitoring system that detects and reports failures automaticallyResult now(June 2023):series of 36 modules in 24/7 operation for over one yearMore than 50,000 deposits analysed,unambiguous detection,immediate reporting of failures8/27BeST Sensor Wastewater Pump Project JROV2201,Ol

9、iver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmEmbedded Signal Processing:Cloud vs.EdgeCloud Computing requires only simple nodes all data collected into the cloud powerful central processing,but must be onlineEdge computing processing performed locally keeps traffic low can hand

10、le interrupted connections cloud functions optionalSensing Modules.9/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmDetect Wastewater Flow with Machine Learning?Inputtraining datawith annotationsOutputmodel that associates patterns

11、Decisive factors:training data must be extensivedistribution must be homogenous10ML example:iPhone iOS 16.5.1 search for Hund(dog)?OK?OKOKOKOK(Text)/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmHomogenous Distribution?For ML to w

12、ork,training data must reflect the universeif yes,fine(A)if not,failure(B)if sometimes,results are mixed(C)often,we do not know example:pump monitorImage Source:Thomas R.Schwarz/Wikipedia11ABC/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched

13、.co/1LdWmDomain-Specific Knowledge HelpsExample:ECGreflects activity of heartexperience of medical expertsExample:Pump monitoringknowledge about wastewaterreflects water flowchanges with temperature etc.Real-world experience countsAI does not replace human knowledgeOliver VlckersGeburtsdatum:03.10.1

14、962(Alter 60)Aufgezeichnet am 23.07.2022 um 17:03Sinusrhythmus 63 BPM Dieses EKG weist keine Anzeichen von Vorhofflimmern auf.12ECG example(OV,Apple Watch)/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmReal-time Signal ProcessingP

15、attern recognitiondo it as early as possibleuse all available processing powermust be fast enough to always catch up with sensor data streamUse adequate resolutionmore is not always betterreduce frequency if possibleCategorization of signalContinuous signalSignal Processing(Filter)State Machine(cont

16、ext)Evaluation of pumping processPump monitor example13/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmExplanation ComponentTraditional AI is black boxtraining cannot be tracedwhy does horse appear as dog?!errors unacceptable for m

17、edical&securityExplanations can be providedrules for filtering can be documentedlogic of conclusions can be tracedrationale can be generated automatically!Pump monitor exampleWHY?Because-pumping duration 10s-no longer breaks-always minimum pressure of xyz mBar14/27BeST Sensor Wastewater Pump Project

18、 JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmSummary:Embedded Signal ProcessingSignal processing is hardthere are no shortcutsgood algorithms require years of experienceexcellent algorithms are precise and fastDomain knowledgeis required for an excellent systemwitho

19、ut domain knowledge,system has prejudiceAI helps to build knowledge base,but not sufficient 15#EMBEDDEDOSSUMMITPump Monitor:Zephyr Firmware Application Overview Firmware Power Management Lessons LearnedPrague,June 26-30,2023/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert

20、,Prague,June 27,2023https:/sched.co/1LdWmScope of the Application1.Read NFC tags2.Monitor pressure samples3.Provide direct user feedback LED bar responds to pressure4.Evaluate pressure gradient,report5.Send to MQTT broker via LTE-MPump Monitor PCB,LED Board and NFC Antenna17/27BeST Sensor Wastewater

21、 Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmHardware ComponentsDevice power usage more important than interfaceHardware Block Diagram of the Pump Monitor18/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023h

22、ttps:/sched.co/1LdWmChoice of Modules important to meet the BriefThreads,workqueues,timer APISensor-,LED-and storage APIs(on-device,SD card)Nordic nRF-Connect SDKModem support for nRF9160Driver for NFC reader(ST25R3911B)MQTT,JSONPower management subsystem19/27BeST Sensor Wastewater Pump Project JROV

23、2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmSystem StatesAccelerometer wakes up systemStart pump monitoring if:A.NFC tag readB.Pressure below threshold detected50 Hz pressure sampling frequencyMost of the energy consumed in pump monitoring20Main States of the Applicatio

24、n/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmMinimized Pressure Sensor Current in SensingPressure sensor mostly offCurrent Diagram-2 s Pressure Sensor sampling during SensingPower Profiler powering the Pump Monitor PCB21/27BeST

25、 Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmFrequent NFC Polling:Optimal Readability10 Hz polling frequency for good responsiveness-No user input-System just worksCurrent Diagram-100 ms NFC polling Interval 22/27BeST Sensor Wastewater

26、 Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmTypical Energy Impact of CPU and Devices50 Hz pressure sensor sampling rateCheap(energy)CPU timeTemp-/Humidity sensor AccelerometerExpensive(energy)RadioPressure sensorNFC readerLEDs-Cheap CPU time enables Ed

27、ge computingCurrent Diagram-20 ms Pressure Sensor Sampling during Monitoring23/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmIssues to solve when Switching off DevicesAnalog pressure sensor20 ms warmup timeno re-initializationTI L

28、P5569 LED controller set chip_en Register after power onDevice power managementApplication or driver triggers device power managementpm_action function called on PM eventsdevice voltage controlled by regulatorPM Implementation in the LP5569 Device Driver24/27BeST Sensor Wastewater Pump Project JROV2

29、201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmDesign DecisionsPower gating vs.always onDisabling power for the LP5569 LED driverRe-initialize LP5569 allows hot-plugging5 V requirement pressure sensorRobust sensor more importantMQTT/TLS/TCP vs.Lw2M2/CoAP/DTLS/UDPSD card for

30、 logging pressure samples State of the LTE-M/NB-IoT Network was unknown25/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1LdWmLessons LearnedDevelop features in application modulesSpecification(HW)vs.Rapid prototyping(SW)Some requiremen

31、ts had not been defined at project startNFC Tag FormatStart of pumping process if no NFC Tag availableField test with limited number of devicesOpportunity to learnLTE-M network reliable26/27BeST Sensor Wastewater Pump Project JROV2201,Oliver Vlckers,Jonas Remmert,Prague,June 27,2023https:/sched.co/1

32、LdWmOperationsMQTT to SQL database for monitoringDaily telemetry statisticsHumidity,temperatureWake-up cyclesActive time(Sensing,Monitoring)Water intrusion alarmWhats next?27Water Intrusion#EMBEDDEDOSSUMMITQuestions?28Oliver Vlckers,BeST Berliner Sensortechnik GmbHovbestsensor.deJonas Remmert,Phytec Messtechnik GmbHj.remmertphytec.deZephyr Project Page:https:/www.zephyrproject.org/portfolio/best-sensor-pump-monitor-jrov2201/Prague,June 26-30,2023