Introducing the Open Source Hydroponic NPK Calculator

If you are a hydroponic enthusiast or farmer, you know how crucial it is to ensure that your plants get the right nutrients to thrive. One of the essential nutrients required by plants is NPK (Nitrogen, Phosphorus, and Potassium). The correct ratio of these nutrients is crucial to maximize plant growth and yield. However, getting the right balance can be tricky, especially for novice growers.

To make things easier for you, we are excited to announce the open-source release of the Hydroponic NPK Calculator. This calculator simplifies the process of calculating the correct NPK ratio for your plants by providing you with a simple tool that automates the process.

The Hydroponic NPK Calculator is an easy-to-use web-based tool that allows hydroponic farmers to calculate the required amount of nutrient solution based on the desired concentration and water volume. The calculator is written in HTML, CSS, and JavaScript and is free to use and modify under the MIT License.

How to use the Hydroponic NPK Calculator

Using the Hydroponic NPK Calculator is very straightforward. All you need to do is:

  1. Enter the water volume in liters.
  2. Enter the NPK ratio in the provided fields. The NPK ratio is the percentage of Nitrogen, Phosphorus, and Potassium in your nutrient solution.
  3. Enter the desired concentration of NPK in ppm (parts per million).
  4. Click on the “Calculate” button to get the required amount of nutrient solution in milliliters.

The calculator does the rest and provides you with the required amount of nutrient solution in milliliters. You can then add the nutrient solution to your water tank to get the correct NPK ratio for your plants.

Why use the Hydroponic NPK Calculator?

The Hydroponic NPK Calculator simplifies the process of calculating the correct NPK ratio for your hydroponic plants. With this tool, you can ensure that your plants receive the right balance of nutrients to maximize growth and yield. The calculator also saves you time and minimizes the risk of over-fertilization, which can harm your plants.

Moreover, the Hydroponic NPK Calculator is open source, which means that you can modify and adapt it to your needs. You can also contribute to its development by reporting bugs, suggesting improvements, or submitting pull requests.

The Hydroponic NPK Calculator is a simple but powerful tool that simplifies the process of calculating the correct NPK ratio for hydroponic farmers. With this tool, you can ensure that your plants receive the right balance of nutrients to maximize growth and yield. Try it out and let us know what you think!

Open Hydroponic NPK Calculator

Playing with SDR, ADS-B (Plane Tracking), and what is next

What even is SDR?

SDR stands for Software Defined Radio. In short, it is a piece of software that runs on your computer and enables you to use your computer’s sound card as a receiver.

If you’re unfamiliar with SDR, then you may not know that it has been around since the 1980’s, and was originally known as direct conversion receivers (DCR). An example of what a modern SDR “kit” looks like is below:

SDRs are commonly used as a hobbyist application. Most people have at least heard of them, and know they do what their name suggests – define radios!

What can you do with an SDR?

You can do various different things using an SDR as follows:

  • Receive broadcast radio
  • Amateur radio
  • Radio astronomy
  • Track ships via AIS transmissions
  • Track aircraft via Mode S transponder (And this will be today’s project)
  • Listen in in “walkie talkies”

Project 1: ADS-B – Tracking Planes

Back in January, I started to play around with SDR, mostly in order to be able to track aircraft using their Mode-S Transponder signals.


My ADS-B station is currently running the following hardware:

SDR Dongle: AirNav RadarBox FlightStick

Antenna: AirNav ADS-B 1090MHz External Antenna

Board: Raspberry Pi 3 Model B+

Enclosure: Random box bought at the local supermarket, and some DIY hot-glue stuff

Network connection is currently done via Wi-Fi


This station is currently running the PiAware image, including dump1090-fa (that will out of the box feed data to, with some additional software installed to feed into some other sites:

Some other websites/services do it the other way around though, by connecting (while having the relevant firewall exceptions) my station to obtain data, instead of the other way around, these services are:

And some other additional software for metrics purposes:


I have been gathering aircraft tracking data since January 2022 with this setup, and these are some metrics of this data, but before sharing the numbers I’ll share my maximum theorical range (according to at my antenna location, taking terrain into consideration for airborne targets (where red represents the horizon visual range, orange for targets at 10k feet, and the blue line for targets at 30k feet):

Versus my actual range:

If you want to check the live feeds you can do so here:

ADSB Stats Logger:

Data range: 2022-03-08 13:14:53 - 2022-09-03 13:38:11
Unique Flights: 1600
Unique Operators: 522
Max Altitude: Flight SAT408 37.206644315757394 km at 2022-08-19 21:38:10
Max Speed: Flight MEDIC16 1836.0728000000001 kmh at 2022-05-29 22:10:01
Max Station Distance: Flight AFR457 664.5046626435085 km at 2022-07-21 03:33:57
Min Station Distance: Flight RYR2624 0.012642261112371317 km at 2022-05-15 19:38:21
Max Signal: Flight UAL216 -0.9 db at 2022-06-02 11:22:28
Min Signal: Flight AEA194 -28.6 db at 2022-08-04 07:52:23

graphs1090 (6 months period)

Whats next?

In the last few weeks I have been playing around with a couple new SDR things to make an upgrade to my SDR setup with a new project, these things are:

AIS Ship Tracking

AIS Ship Tracking

Listening to Air Traffic Control

Santa Maria ATIS
Ponta Delgada ATIS

I’m currently waiting for Amazon to deliver some adaptors and connectors, so I can connect further gear to my external antenna to develop both these two projects, so stay tuned for future posts about them 🙂