Temperature Sensors v2 (with SHT40)
About This Infographic
A four-column comparison of the temperature sensors used in this course. It adds the high-accuracy I2C SHT40 to the single-wire DHT11/DHT22, the I2C BME280 (which also reads humidity and pressure), and the waterproof 1-Wire DS18B20 probe. Each column shows pinouts, key specifications, and guidance on when to use that sensor. Click each column to see its facts, then use Quiz Me to test which sensor fits a given job.
The SHT40 column uses a real photo of the purple breakout board from the SHT40 lab. The original three-column poster is still available as Temperature Sensors.
Which Sensor Should I Pick?
| Sensor | Measures | Interface | Temperature accuracy | Typical price | Choose it when |
|---|---|---|---|---|---|
| DHT11 | Temperature, humidity | Single-wire | ±2 °C | $1–$2 | You want the simplest, cheapest indoor sensor |
| DHT22 | Temperature, humidity | Single-wire | ±0.5 °C | $2–$4 | You want a better DHT with a wider range |
| BME280 | Temperature, humidity, pressure | I2C | ±1 °C | $2–$4 | You are building a weather station |
| DS18B20 | Temperature only | 1-Wire | ±0.5 °C | $1.50–$3 | You need waterproof sensing or many probes on one wire |
| SHT40 | Temperature, humidity | I2C | ±0.2 °C | $1.65 | You want the most accurate readings |
Prices are typical eBay prices for one module, before shipping. They change from seller to seller.
Good Sensors Can Also Be Inexpensive
A sensor does not have to cost a lot to be good. The SHT40 is the most accurate sensor on this poster, and it is also one of the cheapest.
I bought several SHT40 boards on eBay for US $1.65 each, plus US $1.30 for eBay SpeedPAK Standard shipping from Shenzhen, China. They arrived in about a week. The same board costs about $7 from Adafruit, which ships faster but costs about four times as much.
Cheap boards are sometimes labeled wrong. When yours arrives, run the I2C scanner in the SHT40 lab to check what you really received.
How This Poster Was Made
Unlike most posters in this section, this image is not drawn by an AI image tool. It is an HTML page rendered by headless Chrome, so the text is exact and the SHT40 column can use a real photo.
- Poster source:
src/posters/temperature-sensors-v2/poster.html - Build script:
src/posters/temperature-sensors-v2/build.py
To change the text, edit poster.html and run the build script. The script
redraws the image and moves the click zones to match, so you do not need to
calibrate them with ?edit=true.
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