Because the OmniTemp sensor is made of metal, it will exchange heat with your iOS device if plugged directly into the audio jack. With the included extension cable, you can thermally insulate the sensor from the iOS device to accurately measure the ambient temperature. Due to the thermal mass of the cable, please allow a few minutes to adjust to the surrounding temperature.
Special Note for users using OMNITEMP for NASA's Temperature Change during Totality project
Adding an air circulation device such as a fan to blow air at the sensor facilitates heat exchange with the ambient air and makes the sensor more sensitive to temperature change. However, please make sure the fan is at a reasonable distance from the sensor or you will impact the temperature reading due to the heat generated by the fan motor.
Here are some additional tips to improve sensor accuracy:
OmniTemp sensors are carefully designed to meet strict specifications, but you can calibrate your sensor to make it even more accurate, up to +/- 0.1 degrees Celsius. There are two modes for user calibration: single point calibration and dual point calibration.
If you have access to one known, stable temperature source, you can use this method to eliminate OmniTemp offset errors at this known temperature. Please note that this known, or reference, temperature must be in the normal operating range of OmniTemp. To use single point calibration, follow these steps:
The offset value is applied to all temperature readings.
If you have access to two known, stable temperature sources, you can use this method to eliminate OmniTemp offset error reading at these known temperatures and apply a weighted offset to temperatures in between. We recommend that the two known temperatures be at least two degrees Celsius apart. To use dual point calibration, follow these steps:
The offset values at Reference Temperatures are applied to all temperature below and above Low and High Reference temperatures respectively.
The OmniTemp app allows you to set notifications, or alerts, to let you know when the temperature rises above or falls below certain values. To set these notifications, tap the Settings on the lower right corner of the app. Enter the desired values for one or both alerts, then tap on Done.
OmniTemp can log its temperature readings to a file stored on your device. To enable logging, go to the OmniTemp settings and turn on “Save data to file". When enabled, this option will record about 15 temperature readings per minute. Enable logging only when you need it to avoid taking up unnecessary storage on your device.
To delete the log, tap the Clear button.
To include your current GPS coordinates in the log, turn on the “Include location” option found in the Logging section of the OmniTemp settings.
The log file is formatted as comma-separated values (CSV), where each row corresponds to a single temperature reading and the columns are as follows:
Column 1: Date and time of the reading (format: yyyy-MM-dd HH:mm)
Column 2: Temperature reading (in Celsius)
Column 3: Location in degrees latitude (if "Include location" is enabled)
Column 4: Location in degrees longitude (if "Include location" is enabled)
To retrieve the log, plug in your device to a computer and launch iTunes. Open the settings page for your device and go to the Apps settings. Look for OmniTemp under the File Sharing section and click it. You can then drag-and-drop a copy of the log file (temperatures.csv) to your computer.
The Settings screen at the bottom right corner of the app allows you to provide feedback to us. We care about your opinion and appreciate getting feedback on how we can improve.