Digital signal processing (DSP) in golang, frequency spectrum analysis with FFT, and r-peak detection.
This article will show how golang can be used for digital signal processing (DSP) on a raw PPG or ECG heartbeat signal. We will use the fast Fourier transform (FFT) to look at the frequency spectrum, clean up noise from the signal using low and highpass filter, and finish by implementing r-peak detection on the signal to calculate the r-interval and the average heartbeat.
To outline the different steps,
- Read and visualize the signal
- Frequency analysis with FFT and signal filtering
- R-peak detection and heartbeat calculation
- …
Part 2 in the complete flutter app walkthrough. Designing an onboarding and authentication flow with the bloc framework.
This is the second post in a series on how the Dreamwod app is built. The Dreamwod app is an iOS and Android app for CrossFit athletes where they can track their progress and for CrossFit gyms that want their athletes to engage in their community. We have previously described the components and package used to build a “details page” in the app. …
Components, best practices, and tools used to build a large Flutter app.
This is the first post in a series on how the Dreamwod app is built. The Dreamwod app is an iOS and Android app for CrossFit athletes where they can track their progress and for CrossFit gyms that want their athletes to engage in their community. We have previously described how we have created some of the backend services (Golang + CloudRun at Google Cloud) and now it’s time to discuss the app.
The series contains (at least) the following posts.
- Components used for building the details page…
Secure asynchronous processing with Cloud Run through Pub/Sub.
Background
Cloud Run will throttle the CPU when there isn’t an active request processing. That means that it isn’t possible to spawn a new thread or goroutine to do background processing within a Cloud Run API. Background processing can for example be to send an email during registration or to send push notifications when a user likes a post, something that the user doesn’t have to wait for.
This article will describe a solution for asynchronous processing where an API running on Cloud Run will send events to Pub/Sub. …
Migrating a golang REST API from Kubernetes Engine (GKE) to Cloud Run
Background
Kubernetes at Google Cloud (GKE) was used during the development and the testing of the Dreamwod app (https://www.dreamwod.app). GKE has been working good but it has also been the most expensive and complicated part of the hosting. We have because of that been migrated from GKE to Cloud Run. The primary reasons behind the migrations are.
- Cost - Cloud Run is cheaper than GKE (for our workload).
- Simplicity - Our API is pretty simple and we don’t need a lot of the extra features in Kubernetes.
Migrating secrets
When migrating…
Erik
Developer, backend, frontend, ML. Likes crossfit and training. Building on the app dreamwod.app.
