Acquiring and Characterizing IoT Sensor Signals

Figure 1: IoT devices use many sensors to collect data
about their ambient environment

If we recall our earlier post with its definition of what constitutes an Internet-of-Things (IoT) device, one of the main functions of such devices is to sense its environment and digitize the collected data. Often, an IoT device uses many sensors to collect information about its environment (Figure 1). Having the ability to capture and analyze signals from numerous sensors simultaneously is critical to ensure proper and optimal functionality of the IoT device's design.

Viewing all of these signals on an oscilloscope at once is made much easier with a sensor acquisition module. One example of such a device is Teledyne LeCroy's SAM40 sensor acquisition module, which provides as many as 24 input channels for low-frequency sensor signal acquisition and analysis (Figure 2). The SAM40 connects to one of Teledyne LeCroy's four- or eight-channel, 12-bit HDO oscilloscopes to deliver analog plus digital plus sensor acquisitions.

Figure 2: The SAM40 sensor acquisition
module teams with an HDO8000
oscilloscope for unified views of
IoT systems

For system debugging and analysis of deeply embedded designs such as IoT devices, the SAM40 provides additional channels for lower-bandwidth, high-resolution measurements. Systemizing a 24-channel SAM40 module with an HDO8000 (eight-channel) mixed-signal oscilloscope results in eight analog oscilloscope channels at up to 1 GHz with 12-bit resolution, 16 digital input channels, and 24 low-frequency sensor input channels. It's not unusual for engineers to use multiple instruments to debug and validate complex, deeply embedded systems. The HDO8000/SAM40 provides a consolidated view of system performance.

The SAM40 module can be supplied with eight, 16, or 24 input channels, all of which sport 24-bit resolution. It provides 40 kHz of bandwidth (100 kS/s) and 2.5 Mpts/channel on all channels, which equates to 25 seconds of capture time at 100 kS/s. An important aspect of the SAM40 is that it supports 65 different SI and English system units in 13 categories. As can be seen from Figure 2, the module fits neatly within the footprint of the HDO oscilloscopes so it won't take up additional bench space.

At the end of the day, debugging and validating IoT sensor signals is a complex puzzle that involves a lot of interaction between inputs, controllers, memory, and power buses. The SAM40 sensor acquisition module, coupled with an HDO 12-bit oscilloscope, provides an in-depth view of what's really going on in a deeply embedded system such as an IoT device. The multi-grid display layout of the HDO enables us to see the dynamic behavior of all aspects of the system.

Previous blogs in this series:

Debugging the IoT
Anatomy of an IoT Device
IoT Digital Power Management and Power Integrity
Investigating IoT Wireless Signals
Investigating IoT Wireless Signals (Part II)