SPECTECS TEMPERATURE SENSOR WITH ALARMS ( Wi-Fi enabled with optional module ) Embedded control EMC1001 sensor Range 0C to +125C Resolution 0.25C Accuracy +/-1.5C, 40 to 85C USB powered or external 2.2-16V Measurement interval ~2 seconds Continuous, standby & single-shot modes Standalone operation or serial terminal user interface 3 user set alarm thresholds etc Generates visual alarms Audible alarm ( buzzer needed ) Alarms extendable Alarm toggled 0V/3.3V output PWM output for SSR, motor driver User programmable firmware Simple driver installation Dimensions 75mm x 45mm Weight 16 gms Optional Wi-Fi module Introduction The SpecTecs Temperature Sensor with Alarms module is a complete temperature measurement and alarm system under the embedded control of a PIC micro-controller unit, ( MCU ), with a small footprint, making it suitable for embedding in, particularly space limited, applications and where critical temperature monitoring and control are required. Uses are : Embedding in applications, projects & equipment requiring accurate, sensitive and responsive temperature measurement, control & alarms. Description The SpecTecs Temperature Sensor with Alarms module is based on the EMC1001 temperature sensor chip present on a Microchip PIC development board, comprising also the PIC, programmer, usb interface, status ( red ) and power ( green ) visual indicators, ( LEDs ). The module is provided preprogrammed. The user can, however, re-program with a backup copy of the software or to update with the latest firmware as and when available with a quick and simple computer mouse click and drag operation. A usb connection provides the serial interface to a pc as a virtual terminal emulator running the users choice of software, e.g., Teraterm, CoolTerm, SpecTecsTerm # et al. via a virtual comport. A green power indicator LED is turned on when power is applied. This briefly changes to red when software is being uploaded. Red LED, D2, turns on for the duration of each temperature measurement cycle ( blink period approximately 2 seconds ). D2 is also turned on continuously while in menu mode and when processing switch S2 activity. The alarm conditions are defined as follows:- ( There are visual alarm status indicators, red LEDs D3, D4 & D5 ). THERM1, Alarm1. The alarm is activated if the measured temperature exceeds the set threshold value and is de-activated when the temperature falls to the threshold less hysteresis value. Status indicator is LED D3. THERM2, Alarm2. Two limit values can be set; a high limit and a low limit. The THERM2 high alarm is activated if the measured temperature exceeds the high limit and the THERM2 low alarm is activated if the measured temperature is below the low limit. The set hysteresis value applies. Status Spectrum Technologies 2011-2018 All rights reserved 1
indicator LEDs are D4 ( high limit alarm ) and D5 ( low limit alarm ). Alarm event toggled OV/3.3V ( max 50mA ) switched output is provided e.g., if required to drive a mechanical relay or buzzer. A pulse width modulated ( PWM ) alarm triggered output ( 3.3Vpeak-peak, frequency 10Hz ), is provided on the THERM1 and THERM2 high alarms for driving a solid state relay ( SSR ) or motor ( e.g., fan ) speed control circuit. The duty cycle changes automatically from 40% to 100% with the measured temperature 0C to >5C in excess of the alarm threshold value. Note that 40% duty cycle PWM output remains until the temperature has dropped below the threshold minus hysteresis value. Visual, audible alarms and the PWM output can be extended from one of the board headers There are three configurable temperature threshold and limit values which trigger alarm events, a configurable hysteresis ( difference in alarm on/off temperatures ) and selectable modes of operation, all of which can be accessed and managed from the menu. Initial default temperature threshold, limits and hysteresis are preset as follows when the module is shipped:- Therm1 threshold 50C, Therm2 high limit 127.75C, Therm2 low limit 2.25C & hysteresis 2C. Any user defined values within range which are subsequently entered via the menu will overwrite the initial defaults and be saved in non-volatile memory. These user defined values are not lost on power-down and will still be retained even after the module has been reprogrammed. The last used mode, continuous or standby, is saved for recall on next program start. In use Driver download and installation Connect the Temperature Sensor module to a pc with a usb cable. The module requires a micro usb plug. Download the Microchip cdc ( communication device class ) driver from www.microchip.com/mplab/mplab-xpress using the downloads tab which will enable a virtual serial port ( com port ) to be created for it. Create a folder on a local drive called e.g., CDC_Driver and extract the zip file to this folder. The required driver file for Windows is Navigate to the Device Manager window, go to Other Devices, find Microchip Composite Device and install the driver. After completing the driver installation, notice that a new virtual com port has been declared as a new usb-serial port. Driver installation is now complete. Uploading firmware The Temperature Sensor module is supplied already programmed together with a backup copy of the firmware code file ( ); n.nn is replaced with the latest version. Should the module require reprogramming, locate the saved hex file and, with a mouse, click and drag the file to the drive labelled XPRESS. The green power LED will briefly turn red during the upload. Initial setting up Before positioning the module in its intended location it should be checked and any settings changed as appropriate to its operation. Using the terminal program of your choice, configure a new serial connection using the declared com port; 9600Bd, 8bits, 1 stop bit, no parity and no flow control. Connect the module and open the port from the terminal software. Notice that the displayed text scrolls approximately every two seconds; the measurement interval time. The module is in the last used measurement mode, continuous or standby. If in continuous mode touch the module in the vicinity of U5 and notice that the displayed temperature changes. Some product information, default hysteresis and temperature thresholds are displayed. Display the menu by pressing any key. Make changes as required. Note that <S/B> signifies that the module should be in Standby Mode S/B ( menu item 3 ) first. There is a hysteresis fast shortcut feature using switch S2, for setting values of hysteresis, avoiding using the menu. Incremental changes can be made by pressing switch S2, in either continuous or standby modes. If any errors have been made when entering new values, press switch S1 to reset the software and begin again. If Single shot mode is selected the module will perform one temperature conversion, display the result and return to Standby mode. Note that the displayed text still scrolls approximately every 2 seconds as the software continues to loop; but no new temperature measurement will be made until the module is placed in Continuous mode. Details of any alarms which have asserted are displayed. In the target application Position the module as close as possible to the heat source ( hot-spot ) of interest. Extend any visual, or audible alarm driven outputs to a convenient location for viewing or hearing by connecting as follows:- THERM1 alarm 1 LED, board header J8, RC5 & GND*. THERM2 alarm 2 LED, board header J8, RC6 & GND*. Spectrum Technologies 2011-2018 All rights reserved 2
* Connect 680Ω 1/8W resistor in series with each LED. Connect any required mechanical relay or compatible buzzer as follows:- board header J8, RC2 & GND. ( 0V/3.3Vdc max load 50mA ). A buzzer will give an audible indication when any or all alarms are asserted and turn off when no alarm is asserted. A single control line, PWM, is provided for a solid state relay ( SSR ) or motor driver. If required connect a DC motor ( fan, blower etc ) driver circuit, or SSR, to the PWM output, board header J8, RC7 & GND. There is an expansion socket available, comprising J5 & J6, for a mikrobus compatible DC motor driver. ( The Mikroe-2893 DC Motor 8 Click board has been tested with the Temperature Sensor module; see Fig. 6a & Fig. 6b ). If already configured the module will not need a usb connection unless required for power or the terminal interface. It can be used in a stand-alone manner if not usb powered by connecting an external power supply or battery(s) with voltage in the range 2.2Vdc to 16Vdc to the connector labelled, observing the correct polarity. Alternatively a usb power bank can be plugged into the micro usb socket. Note that (i) R15 is currently unused, and has no effect, and (ii) R21 is intentionally absent. The latest firmware version is always stated in the Annex - Change Log of the latest issue of this document. The file ( n.nn replaced by the latest version number ) will be sent by email to Purchasers of the Temperature Sensor with Alarms module on request. # ( see Fig 7 ) is our own pc serial terminal software ( for Windows ) for SpecTecs projects and applications. It s development is ongoing. It is supplied as is without guarantees on its functionality, and is a free download. Download from www.spectecs.com/download.html Fig 1. Example showing how to break out the visible and audible alarm indicators from the module board header J8 using 2 LEDs and a buzzer Spectrum Technologies 2011-2018 All rights reserved 3
Using the Wi-Fi module Introduction A 2.4GHz, 802.11b/g/n compliant Wi-Fi module is available as a cost option. The Wi-Fi module sends text message notifications of temperature threshold alarm activity to a wi-fi connected smart phone anywhere in the world where there is wi-fi access. In order to display these notifications, the platform is used. PushBullet is an application for making it easy to share ( push ) notifications, messages, conversations and various other types of media between nominated mobile devices, laptops, PCs etc. Further details of PushBullet can be found at the PushBullet website PushBullet setup ( Tested using Google Chrome browser ) Visit Open an account with a Google or Facebook login. Free version up to 100 pushes per month; there is a charge of $4.99/mo for unlimited pushes. ( Subject to change ) In Setup configure at least your phone. Other devices and features are useful but optional. Go to Settings > Account > Access Tokens and create an access token. It will be of the form o.abc. ; copy and paste this in an email to as Spectecs has to embed the access token in the Wi-Fi module firmware before the module is shipped. Download and install the PushBullet App on your computer. Installing the PushBullet extension in the Chrome browser is recommended. Visit Google Play Store. Download and install the PushBullet App on an Android or IOS smart phone. Wi-Fi module installation ( Refer to Fig. 2 ) Note that when the Wi-Fi module is installed, the expansion socket, comprising J5 & J6, will not be available for other purposes e.g., for a mikrobus compatible DC motor driver. Hold the Wi-Fi module so that the printed antenna is visible, and the 3V3 pin is positioned at the top left. Insert the Wi-Fi module pin header into J5 on the Temperature Sensor board with the 3V3 pins on each corresponding. The remaining 3 pins on this row of the Wi-Fi module will be inserted into their correct positions on J5; from left to right RB5, RB4, & RB3 corresponding to RST, EN & TX on the Wi-Fi module. Note that the next parallel row of pins on the Wi-Fi module does not mate up with J5. Connect the green or brown wire to J8 GND. Connect the white wire to J8 RC2. ( The connections between Temperature Sensor and Wi-Fi module could be extended in order to position the Wi-Fi module separately. ) Wi-Fi setup As supplied, the Wi-Fi module s embedded firmware contains the PushBullet access token, but not the credentials of the wi-fi network with which it will be used. These need to be set on first use only. Thereafter the Wi-Fi module will connect automatically to the specified wireless Access Point ( AP ); typically your home network wireless router. Your router should be positioned close by. Switch on your computer. These instructions assume a Windows machine. Log in to PushBullet on your smart phone. Install the Wi-Fi module as above and connect a dc power source ( usb connection, usb power bank, battery, external mains powered dc power supply ) to the Temperature Sensor. The Wi-Fi module initialises and configures itself as an AP with SSID and IP address. Spectrum Technologies 2011-2018 All rights reserved 4
Using your computer, click on available networks ( or network connections ) icon in the task bar notification area. should be one of those listed. Connect to SSID SpecTecs_TempSens. Open a browser ( tested with Chrome ). In the address field enter 192.168.4.1 which will open a wi-fi configuration page - Click Configure Wi-Fi No Scan. Your wi-fi network SSID and password are shown. Click on Save to save wi-fi network credentials. If you are already logged in to PushBullet on your smart phone, you will see a notification sent from the Temperature Sensor after a few seconds. In future use the Wi-Fi module will automatically connect to the same wi-fi network AP, on power up. If wi-fi network AP credentials change or another wi-fi network SSID is chosen, the process has to be repeated. Notifications will only sent if there is a change in temperature threshold alarm status; OFF>ON, ON>OFF. An example of notifications pushed to a smart phone is shown in Fig. 3. Fig 3. Notifications displayed on a smart phone using PushBullet Fig 2. Wi-Fi module ( right ) shown plugged in to the Temperature Sensor with Alarms Spectrum Technologies 2011-2018 All rights reserved 5
Feedback is welcome to info@spectecs.com The Temperature Sensor with Alarms is for measuring air temperature only, and should not be immersed in any liquid. The supplied software code file may be copied for backup purposes and personal use in conjunction with the purchased module, and not distributed or resold without permission from Spectrum Technologies. Spectrum Technologies accepts no responsibility for any damage caused to the product described herein by any apparatus connected to it, nor caused to such connected apparatus, nor for any errors or omissions in this document. Any use by the purchaser of the product implies acceptance. The specification, features, functions and appearance of this product may change without notice as required by any future product development and improvement. ( see ). Acknowledgements : The development board is a product of Microchip Technology Inc. Windows is a registered Trademark of the Microsoft Corporation. mikrobus and Click Boards are registered trademarks of MikroElektronika. Enjoy using the SpecTecs Temperature Sensor with Alarms - the SpecTecs team Fig 4. Example of terminal displaying the Menu ( CoolTerm in use ) Spectrum Technologies 2011-2018 All rights reserved 6
Fig. 5 Example of terminal display in Continuous mode ( TeraTerm used ) Spectrum Technologies 2011-2018 All rights reserved 7
UserGuide_TempSensor_with_Alarms.pdf Issue 1/23-06-2018 Issue 2/24-07-2018 Issue 3/19-10-2018 Issue 4/25-10-2018 Firmware Annex Change Log Temp_Control_ V1.00.hex first full release version 12-07-2018 Temp_Control_ V1.01.hex 29-08-2018 Fig 6a. Motor driver circuit board fitted to the mikrobus expansion socket Fig 6b. Setup to demonstrate temperature control of the speed of a 12Vdc fan Spectrum Technologies 2011-2018 All rights reserved 8
Fig. 7 Example of terminal display in Continuous mode ( SpecTecsTerm used ) Spectrum Technologies 2011-2018 All rights reserved 9