Bridging the Gap

Tips and insight to help your business and products join the Internet of Things.

Connecting Analog Sensors to the Internet: Choosing an IoT Data Logger

We may live in the digital age, but it’s still an analog world. Across industries, analog sensors are readily available and generally less expensive than their digital counterparts. Simple voltage, current, resistance, or pulse outputs make analog sensors straightforward to use. They don’t have proprietary interfaces so you have many options for vendors and manufacturers. The downside is that making the data useful – getting it to a network or the internet – is left as an exercise for the user.

It’s not difficult, but there are a lot of options. A quick google search will reveal hundreds of data loggers on the market.

These are the four questions you should ask when you’re choosing an IoT data logger:

  1. Does it support my sensors?
  2. How do I set it up?
  3. Does it support an open IoT protocol (MQTT)?
  4. Is it a complete solution?

Does it support my sensors?

There are data loggers on the market to support any analog sensor you can find – but they’re not created equal. For most applications, the excellent accuracy available in even inexpensive data loggers is adequate. The differentiating factor is universal inputs. Manufacturers reduce costs by allowing only a short list of input types on any particular model. For long term compatibility and expandability, look for a product with voltage, current, resistance, and 4-20mA measurement capabilities.

How do I set it up? 

For decades we’ve been configuring data acquisition systems by connecting a laptop to a serial port and using a proprietary program or a terminal. Some products have switched to a USB port, but you’re still left with the inconvenience of dragging around a laptop.

Today, smartphones provide a convenient alternative. There’s no need to be stuck in the field holding a heavy laptop with a short serial cable and a draining battery. Look for products that can be configured with a smartphone both by direct wireless connection and over the internet.

You shouldn’t need to write code to get your data logger working. Smartphone apps with simple configuration wizards saves you time and avoids mistakes. If the data logger you are considering requires software programming, you may want to consider more modern alternatives.

Does it support an open IoT Protocol (MQTT)?

The Internet of Things is evolving every day. New platforms and services are being developed by companies large and small. You need to make sure that the hardware and software you invest in is sustainable, can evolve, and will have universal compatibility. MQTT is an open standard for IoT communication supported by every major IoT platform. Choosing hardware that supports MQTT ensures that you have a path forward as the Internet of Things evolves.

Is it a complete solution?

A complete solution will have hardware (the data logger), a cloud backend for storing and forwarding data, and a way of retrieving data like a mobile app. Most products are designed for system integrators and only include one piece of this puzzle. Others include all three pieces but only support their own proprietary cloud service and mobile app. Choosing an MQTT compatible end-to-end solution allows you to start with a functioning product out of the box but have the flexibility to change in the future.