Blog 4 - Analog In, Analog Out | Sending Rotation Data Between Micro:bits Using IFTTT and Google Sheets

 

For this project we used a Micro:bit and IFTTT to transfer rotation data from one Micro:bit to another. The idea was to capture rotation values from a Micro:bit attached to a cloud board, log them in a Google Sheet via IFTTT, and then retrieve and display those values on a separate Micro:bit using an HTTP GET request.

This experiment allowed me to explore IoT-based automation, integrating cloud services with physical computing in a straightforward yet effective way.

Capturing and Sending Rotation Data

I started by configuring the first Micro:bit to detect its rotation values and send them to an external service.

Since Micro:bit doesn’t support direct HTTP requests, we had to use a cloud board to relay the data. The values were then sent to IFTTT, which triggered an action to log them in a Google Sheets document. This setup effectively turned Google Sheets into a temporary database.

Once the data was stored, the second Micro:bit needed to retrieve it. We set up a HTTP GET request from another device to fetch the latest values from the Google Sheet. The response was parsed, extracting only the most recent rotation values. Due to difficulties with getting the HTTP GET directly with an API approach, for requests to work we set up a flask server on a laptop to make GET requests.

These are the screenshots where we initially used IFTTT and a python script to handle automation for sending requests and we attempted to have it receive requests as well , but we found it to be too slow. The latency in executing webhooks was inconsistent, which made real-time interactions unreliable.

 

Since we couldn't get http GET requests to work on the micro:bit to retrieve the data from the google sheet, Brendan wrote a python script that would make the requests locally. There is a 3 second pause because the micro:bit could only POST roughly every second so the requests would pile up since the GET requests would be much faster.

Using the Flask server

To improve response times and have more control over the process, we switched to using a Flask server fully. With Flask, we can handle POST and GET requests directly, ensuring faster execution and better flexibility in managing requests. This setup allowed us to customize endpoints, handle data processing efficiently, and reduce the dependency on third-party services. 

 This micro:bit got the rotation angle and sends it to the flask server

The flask has an endpoint which will get the rotation data from the google sheet.

 

The values gathered were then displayed on the second Micro:bit’s LED matrix using the GET request, effectively creating a simple, cloud-based communication channel between the two devices.

 

One of the main challenges was the delay between sending and receiving data. Since IFTTT processes webhooks at its own pace, there was a noticeable lag in real-time updates. While this wasn’t a major issue for logging data, it impacted the responsiveness of the second Micro:bit. This was the main reason we decided to switch to using a flask server instead.

This project demonstrated the potential of combining Micro:bit with cloud services for basic IoT applications. While the setup had its limitations, it provided valuable insights into data logging, webhooks, external API communication and switching to a flask server in a simple but effective way.

 

Comments

Post a Comment

Popular posts from this blog

Blog 2 - HRV Demo

Image
Lab 2 - Simple Heartrate Sensor Demo For the second lab, our task was to explore the capabilities of the Micro-Bit platform by connecting an external sensor to the microcontroller through its' GPIO pins. Readings were aquired through a simple serial read script created in Microsoft Makecode. In this case, the external sensor measures heart rate / pulse by shining a bright green LED light into skin tissue and measuring the light reflected back. As the heart circulates blood around the body, a small variation in pressure occurs within blood vessels, arteries and capillaries. This pressure variation can absorb more or less light at various stages of the heartbeat and is the primary mechanism of the HRV sensor. By detecting fluctuations in light reflected back from the body, it is possible to get an acurate reading on our heartbeat. A similar mechanism of measuring bloodflow is used in other 'smart' technology such as smart watches, fitness bracelets and even in professional me...
Read more

Week 1: HRV Review

Image
  What is it? Heart rate variability (HRV) is the measure of the variation between heartbeats. It is controlled by your autonomic nervous system (ANS). This system operates automatically and regulate process such as the heart rate and other bodily functions that are are not under conscious control. This system is broken into two branches the flight or fight (which preparing the body for action and stress) and the rest + digest (which promotes relaxation + recovery). HRV is influenced by the ability to smoothly shift between these two branches.  High HRV: Larger difference between successive heartbeats - Indicates a more flexible and adaptable autonomic nervous system.  Low HRV: Smaller differences between successive heartbeats - Indicates a less flexible autonomic nervous system.                                                ...
Read more

Blog 5 - FFT & HRV

  Week 7 Project Meeting This week, we discussed a direction we would like to take the HRV sensor in. Using the programs we have created over the past few weeks; the aim is to create a system for monitoring the HRV sensor using the MicroBits.   What is Fast Fourier Transform (FFT) Fast Fourier Transform is an algorithm that helps to identify what frequencies are in a signal. These signals can be anything from audio, communications and biomedical signals. Slower heart rates happen when you're resting or relaxed, and faster rates happen when you're active, stressed or when you’re in danger.   What is HRV https://my.clevelandclinic.org/health/symptoms/21773-heart-rate-variability-hrv Heart Rate Variability is the fluctuation in variability between heartbeats. These variations are very small, adding or subtracting a fraction of a second between beats.   Ethics https://www.geeksforgeeks.org/computer-ethics/
Read more