Forem: Dyami Connell

How I Built a Custom Search Engine for Browning Motor Sheaves

Dyami Connell — Fri, 16 Jan 2026 18:38:02 +0000

The Problem
I work in HVAC Test & Balance (TAB). A big part of the job is identifying specific pulleys (sheaves) on rooftop units to adjust fan speeds.

The old way involved carrying a physical catalog, measuring the part with calipers, and then manually flipping through pages to find a match. If the measurement was slightly off, or the catalog was missing a page, you were stuck guessing.

I realized I could speed this up significantly if I just had a digital database I could search from my phone.

The Build: The "Browning" Engine
I built TestAndBalance.xyz, a simple web app that replaces the catalog.

Here’s how I broke it down:

The Database: I needed the data first. I digitized the specs for over 2,000 Browning sheaves, mapping the physical dimensions (Outside Diameter, Pitch) to the actual Part Numbers and Bore sizes. Now, instead of a book, I have a queryable dataset.
The Search Logic: Field measurements are rarely perfect. A sheave might be rusted, or the angle might be awkward. I set up the search to handle a bit of variance.

If I input 3.4, the logic searches a range (like 3.35 to 3.45) to find the closest valid part number. It acts as a "fuzzy search" for hardware.

The Hardware Interface (Calipers) Since this tool relies on physical inputs, I still need to carry calipers. The software is only as good as the measurement I type in. It helps confirm I'm looking at a "3V" belt profile vs an "A" profile, which is hard to tell by eye but obvious when you measure it.

The Physics Layer
To make it more than just a lookup tool, I added the Fan Laws (fluid dynamics formulas) into the frontend.

When I select a new sheave size, the app automatically calculates the resulting Brake Horsepower (BHP). Since power increases with the cube of speed, a small change can ramp up power usage fast. The app flags the new BHP so I can verify it’s safe for the motor before I even order the part.

Summary
I built this because I wanted a tool that fit my specific workflow. It’s a PWA, so it loads instantly on a job site, and it saves me a few hours of manual lookup time every week.

If you’re interested in automation for the trades or just want to see how it works, you can check it out here: TestAndBalance.xyz

I’m Dyami Connell, an HVAC TAB Technician.

Hacking the Trades: Why I Chose Python for HVAC Field Automation

Dyami Connell — Thu, 01 Jan 2026 04:02:03 +0000

By Dyami Connell

I recently wrote a breakdown of how I built the frontend interface of my tools using JavaScript (you can read that on my Dev.to profile here: [LINK TO YOUR DEV POST]).

But today, I want to talk about the backend—the heavy lifting.

As a TAB (Testing, Adjusting, and Balancing) Technician, the math I deal with isn't just "A + B." It involves fluid dynamics, fan laws, and air density corrections that change based on altitude and temperature.

While JavaScript handles the web interface, I turned to Python to handle the actual engineering logic.

The Problem: The "Bay Area" Factor Here in San Francisco, we deal with microclimates. One job site is at sea level; another is in the hills. Standard calculators often ignore Air Density ratios, which can throw a balance report off by 5-10%.

The Python Solution I built a simple Python library for TestAndBalance.xyz that standardizes these corrections.

Fan Laws: It iterates RPM/BHP changes instantly.

Data Handling: Python allows me to eventually pump this data into Excel or PDF reports using libraries like pandas (something I'm working on now).

Why Open Source Matters for Trades Most HVAC software is proprietary and expensive. I believe the basic math of our trade should be free. By using open-source languages like Python and JS, we can build tools that are accessible to every apprentice and journeyman in the field.

Check out the tools live at TestAndBalance.xyz or view my full portfolio at dyamiconnell.com.

How I Automated HVAC Field Calculations with JavaScript (No more paper)

Dyami Connell — Thu, 25 Dec 2025 00:54:06 +0000

I work as a TAB (Testing, Adjusting, and Balancing) Technician in the HVAC industry.

One of the biggest pain points in the field is doing repetitive math for duct traverses while standing on a ladder. The standard industry formulas (NEBB/AABC) aren't complicated, but doing them on a phone calculator leads to human error.

The Problem Existing apps are either expensive, require a login (impossible in dead zones), or are filled with ads.

The Solution I decided to build my own lightweight tool using React. It's a simple PWA (Progressive Web App) that handles:

Round Duct Traverses (Log-Tchebycheff method)

Rectangular Duct Grids

Zero data collection

The Stack

Frontend: React

Hosting: Netlify/Lovable

Logic: Custom JS for the fluid dynamics formulas.

You can try the live demo here: TestAndBalance.xyz

I'm currently working on a Python script to take these inputs and auto-generate the PDF reports we send to clients.

If you are in the trades and interested in how automation can help field work, check out my other projects at DyamiConnell.com.