RtdTerm

The SpacerLabs "RtdTerm" software enables the features and configuration settings of the MAX31865 Resistor Temperature Detector ( RTD ) to digital converter chip ( see previous post ) to be easily evaluated and experimented with. A 2-wire PT100 RTD has been connected on this occasion; 3 and 4 wire RTDs are also supported.

'RtdTermv1.06' user interface

 

 

PT-100 RTD

Resistor Temperature Detectors ( RTD ) made from Platinum (Pt) are more accurate than thermocouple wires for measuring temperature. A 2-wire PT-100 RTD was tested using a MAX31865 RTD to digital converter chip on an evaluation board, and usb-spi dongle controlled by SpacerLabs "SpiConfig v3.0" software.

The tiny PT100 RTD is just visible on the extreme right

Result of reading measurement data from MAX31865 using 'SpiConfig'

From the MISO ( master in, slave out ) bytes the temperature was found to be 19.92 C.

[ Note: PT-100 has 100 ohm resistance at 0C ].

 

 

 

SPI configurator

Used in conjunction with a usb - spi ( serial peripheral interface ) protocol converter, this tool conveniently confirms the correct spi settings used by a peripheral device prior to developing application firmware on the selected platform. The image below shows the user interface displaying the temperature data read from a MAX31855 thermocouple to digital converter. (Click on image to enlarge).

SpiConfig v3 user interface

 

 

 

Oven Temperature Checker

Measuring temperature using a MAX31855K thermocouple to digital converter chip and Lilygo TTGO T-Display ESP32 board. To be used as an "Oven Temperature Checker" ( OTC ) for comparing actual air temperature inside a domestic oven with the set value.

Type-K thermocouple connected to MAX31855 breakout board

The OTC is unusual as it also acts as a BluetoothⓇ server ( SpacerLabs_OvenCheck ) using the 'Bluetooth Low Energy'  ( BLE ) variant of BluetoothⓇ. Connecting to it with a paired BluetoothⓇ client device ( e.g., a smart phone 📱), having a suitable App installed enables the OTC ready for use. The BLE features of the OTC have been modelled on the standard service and characteristics of the BluetoothⓇ "Environmental Sensing Service", having just the one characteristic for "Temperature" exposed.

SpacerLabs "Oven_Check" App

Many general purpose BLE client App's are available. However, here at SpacerLabs, we have built our own custom App for Android devices, called 'Oven_Check', to make the process of accessing the functions of the OTC quick and easy.