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This project pairs an LM35 analog temperature sensor with Bolt IoT hardware and cloud monitoring to track temperature and flag unusual readings. A related project document describes email alerts for threshold breaches and Z-score analysis for anomalies. It is best understood as a learning prototype—not as validated equipment for regulated pharmaceutical storage.
How the LM35 and Bolt IoT prototype works
The LM35 measures temperature and produces an analog voltage. In the workflow documented in Bolt IoT’s “Alert Me on Temperature Data” tutorial, the sensor’s supply and ground connect to the Bolt device, and its output connects to the device’s analog input. Bolt samples the signal and sends readings to the cloud, where temperature can be plotted and alerts configured. The tutorial was published on March 29, 2019; its setup describes a documented project workflow, not a guarantee that the current cloud interface is unchanged.
The tutorial describes the LM35 this way: “The LM35 is an integrated analog temperature sensor whose electrical output is proportional to Degree Centigrade.” Converting that voltage to a displayed temperature depends on the board’s analog-to-digital converter (ADC), its reference voltage, the sensor variant, and the circuit. A conversion formula from one setup should not automatically be assumed to work for another.
What the LM35 specifications do—and do not—tell you
Texas Instruments lists the LM35’s linear scale factor as 10 mV/°C, its operating range as −55°C to 150°C, and ensured accuracy of 0.5°C at 25°C. These are component-level specifications, not a performance guarantee for the complete monitoring system.
#1 Best Overall
- Rated for full −55˚ to +150˚C range
- Suitable for remote applications
- Operates from 4 to 30 volts
- Low self-heating, 0.08˚C in still air
- Nonlinearity only ±1⁄4˚C typical
System accuracy also depends on matters such as calibration, wiring, placement, and the way the sensor responds in its intended environment. A sensor specification alone does not show that a particular assembled device measures a product’s storage conditions reliably.
How anomaly detection and alerts are described
A related capstone document describes email alerts when readings cross temperature thresholds and the use of Z-score analysis to identify anomalous readings. These details belong to that document’s project description; the available project listing does not independently establish how the feature was implemented or validated.
Rank #2
- BOJACK High Precision Celsius Temperature Sensor
- Operating Voltage:2.7 V - 5.5 V
- Rated temperature range: -40 °C-+125 °C
- Accuracy: ±2°C
- Scale factor: 10 mV/8°C
Threshold alerts and statistical anomaly detection serve different purposes. A threshold alert checks whether a reading crosses a chosen limit. A Z-score approach evaluates how far a reading is from a statistical baseline, typically in standard-deviation units. A statistical outlier is not automatically a sensor fault or a storage emergency; interpreting it requires a defined baseline and a response process.
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Why this is not validated pharmaceutical monitoring
The project listing frames the build around monitoring a pharmaceutical tablet case, and the capstone document gives a storage scenario. The available documents do not establish that the scenario’s specific temperature rules or time limits are current official requirements. Do not use those figures as regulatory guidance without checking the applicable regulator and the storage instructions for the specific product.
Rank #3
- Specified −40°C to +125°C, operation to +150°C
- Low voltage operation (2.7 V to 5.5 V)
- Stable with large capacitive loads
- Less than 50 μA quiescent current
- Qualified for automotive applications
The available project materials also do not show calibration against a traceable reference, validated sensor placement, environmental qualification, a documented alarm-response procedure, validated audit trails, or regulatory approval. That evidence gap means the prototype should not be represented as ready for regulated storage monitoring.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What to check before adapting the project
For a learning build, the project offers a straightforward illustration of taking an analog sensor reading into a cloud-monitoring workflow. For any higher-stakes use, first define the intended temperature range and required measurement performance, then assess the complete system rather than relying on the sensor’s headline specifications.
Rank #4
- Precision Temperature Measurement: Linear 10mV/°C output (0V at 0°C) with ±0.25°C accuracy at 25°C for reliable data
- Plug-and-Play Compatibility: 3-pin interface works compatible with Microbit and most microcontroller expansion boards 5VDC powered
- Robust Design: Four 3mm mounting holes secure the module to prototypes or enclosures; compact size 34×22×9mm, 2.6g
- Wide Operating Range: Measures -40°C to +110°C, ideal for environmental monitoring, DIY projects, and industrial prototyping
- Analog Signal Output: Directly interfaces for real-time temperature logging and control systems, suitable for engineers, technicians, factories, individual DIY, electronic enthusiasts, etc
- Sensor suitability: Compare temperature range and accuracy over the range you actually need, along with interface type and calibration requirements.
- Measurement setup: Confirm the sensor variant, ADC range, reference voltage, wiring, placement, and conversion method.
- Alerts and response: Define thresholds, anomaly criteria, alert delivery, and what a person should do when an alert arrives.
- Platform suitability: Evaluate connectivity, data retention, security, and any validation requirements for the intended use.
- Parts: The LM35 is the clearest named sensor in the project materials. They also identify a Bolt Wi-Fi module, but do not establish an exact model or current availability; verify the model before sourcing it. Breadboard and jumper wires are generic supporting parts.
Bolt IoT separately markets Blake for facility temperature and humidity monitoring, including pharmaceutical and diagnostics settings. That commercial offering is distinct from the LM35 DIY tutorial; its mention does not establish that it is a validated substitute for a particular regulated use.
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Quick Recap
Best Value
- Type: Precision Temperature Sensor.Measuremen accuracy +/- 0.25¡ãC
- Operating voltage: DC 4 ~ 30 V;Rated for full ?55? to +150?C
- Model: LM335Z, suitable for remote applications
- Applications: Ideal for temperature sensing and control applications in a variety of electronic devices.
- Package: Available in a TO-92 package for easy installatio
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