While making projects and doing laboratory experiments, we often need to capture the response from sensors or measure voltage drops across circuit elements for the purpose of debugging. Measuring current flow through components is a must for design of efficient power circuits. We use a variety of instruments like voltmeter, multimeter (DMM), oscilloscope, data acquisition modules, etc. When we need to program and control devices with sensor feedback, Arduino and BeagleBone are frequently used as they are very cost effective and easy to learn platforms. However, their sensing interfaces are very primitive with very low resolution and small range ADCs. The alternative is buying an oscilloscope, which is like bringing an automatic gun to a handgun fight! Oscilloscopes are expensive, bulky and loaded with features that most researchers, let alone hobbyists, never end up using. Clearly there is a huge middle ground here which needs, and deserves, to be filled.
evive gives you a great new way to test your circuits, without needing expensive equipment like oscilloscopes, function generators and data acquisition modules. We have integrated Analog Devices’ 24-bit isolated ADC chip ADE7912 into evive, giving it precision sensing capabilities for IoT, lab testing and debugging. While Arduino’s AVR ADC takes 112us for sensing 0-5V data in 10bit resolution, evive allows you to measure 24bit resolution data in less than 15us, with an accuracy of 3mV for +-5V range, and 10mV for +-30V range. Like any oscilloscope, evive offers two channels for simultaneous measurements, with one channel being optimized for voltage measurement in the 30V range and the other being optimised for both current measurement upto 3A and voltage measurement in the 5V range, with a jumper deciding which measurement is done. The ADE7912 was chosen since it offers an isolated power supply, which allowed us to completely isolate the measurement circuit from the rest of evive, allowing you to measure voltage and current from any circuit without worrying about creating ground loops or inadvertently shorting the probes. When combined, the ADC and evive’s screen make a formidable mini-oscilloscope, with multiple modes of display and ranging the axes of the oscilloscope. The display can be triggered in single, scan and auto modes. The voltage division can be scaled from 20mV to 10V at the press of a button, while the time division can similarly be scaled from 2.5ms to 1ms. evive also allows you to set cursor offset for making measurements onscreen, adjust both channel’s offsets independently and change the level of the trigger with the on board Joystick.
Apart from viewing the graphs on the TFT screen, the data can be logged into the SD card with timestamps provided by the on-board real time clock or can be sent over serial communication. Also our LabVIEW interface allows viewing the graphs on your PC/Mac in real time via a serial USB interface.
With the rapid growth and proliferation of Internet-of-Things and big data, lots of sensor network data is communicated to the cloud for a huge number of applications like weather monitoring, precision agriculture, pollution monitoring and tons of DIY hacks. With inbuilt adapters for Wi-Fi (ESP8266 ESP 12-E), RF (Xbee) and Bluetooth (HC-05), evive is IoT ready and can communicate with the cloud and other devices, with its portability making it ideal for deployment for data collection and experimentation.
Evive’s 24 bit ADC, 1.8″ TFT screen, SD card support, real time clock, serial communication capabilities and menu interface make evive a revolutionary new player in the data sensing and logging arena.