TheLight - your savings partner
An app which saves, tracks and monitors! (But What does it SAVE?)
NAAM pe nahi KAAM pe jao Laala!
Why My Water Geyser Was Robbing Me Blind (And How I Used AWS to Stop It) 💡💸
By Mahee Tailor
Project: TheLight — Your Savings Partner
Built for the Bharat Builds Tour: Environmental Hacks (Waste & Energy)
The "Electricity Bill Jump Scare" We All Know Too Well
There are few moments in adult life that deliver a heart attack quite like opening the monthly electricity bill.
You tear open the envelope (or tap the SMS link with a trembling thumb), stare at the total, and wonder:
“Did I accidentally open an aluminum smelting factory in my spare bedroom? Why is my light bill higher than my rent?!”
Most of us respond in one of two ways:
- Walk around the house like an angry phantom turning off light switches behind our family members.
- Swear we’ll shower in cold water forever, only to abandon that resolution 8 minutes later when winter mornings hit.
During the Bharat Builds Tour hackathon, I decided to stop grumbling and actually build something about it. That’s how TheLight — Your Savings Partner was born.
The Problem: We’re Fighting Invisible Monsters
Here’s the dirty secret about household energy waste: most of it happens when we aren’t even looking.
- The Geyser / Water Heater Trap: Most water heaters come pre-calibrated to a blistering 140°F (60°C). That means your geyser is sitting in your bathroom 24/7, boiling water you aren’t using, burning gas and electricity like a runaway locomotive.
- Vampire Loads: That TV on standby? That laptop charger plugged into the wall while you sleep? That microwave displaying the digital time? They are quietly sucking 5–10% of your total electricity bill just sitting there looking pretty.
- Peak Hour Ambush: Nobody tells you that running your heavy laundry between 5:00 PM and 9:00 PM can cost up to 30% more because the grid is stressed and firing up expensive peaker plants.
I wanted an app that doesn’t just show you a terrifying number at the end of the month, but actually asks:
"Hey, are the fixes we tried last month working?"
The Architecture: Keeping It Lean, Mean, and Cloud-Powered ☁️
When building a tool meant to save people money, your backend can’t be a giant expensive cluster. It had to be 100% serverless, zero-maintenance, and ultra-fast.
[ Your Phone / Laptop ]
│
▼
[ Amazon CloudFront Edge ] ── (Grabs local city & time zone with zero lag)
│
▼
[ Amazon API Gateway ]
│
▼
[ AWS Lambda (Python 3.11) ]
│
├── Amazon Location Service (Places & Reverse Geocoding)
├── DynamoDB (Billing records & habit tracking)
└── Amazon SNS (Peak-hour alerts)
- Amazon Location Service: The Detective That Knows Your Utility Tariffs Electricity rates in Mumbai aren’t the same as rates in Seattle or London. Instead of forcing users to fill out annoying 15-field forms asking for their postal code, DISCOM provider, and grid zone, I used Amazon Location Service (SearchPlaceIndexForPosition) combined with CloudFront Viewer Location Headers. The moment you open TheLight, AWS pinpoints your municipality and loads: Your regional electricity rate (e.g., ₹7.50 / kWh). Your natural gas tariff. Your exact Time-of-Day (ToD) Peak Hours (so it can warn you: "Don't run the wash right now; wait until 9 PM when rates drop!").
- The Famous "Down 19%" Dashboard One of my favorite features in the UI is a clean comparison card: Last Month: ₹2,480 This Month: ₹2,010 Status: ↘ Down 19% — The geyser timer is working. There is something deeply satisfying about seeing concrete proof that installing a simple ₹400 mechanical timer on your water heater actually knocked 19% off your electricity bill.
- Government Schemes Nobody Knew Existed Did you know governments around the world have massive subsidies for rooftop solar (like the PM Surya Ghar scheme), smart meters, and BLDC ceiling fans that cut power by 65%? Most people don't know because government energy portals look like they were designed in 1998. TheLight brings those active subsidies right into your pocket with a one-click eligibility checker.
Human-First Design: "Make It Feel Like a Friend Built It"
Too many developer tools look like an air traffic control panel: 40 graphs, 80 buttons, and dark purple gradients everywhere.
For TheLight, I wanted the exact opposite:
- A Cozy Monochrome Palette: Black, chalk white, and deep zinc that’s easy on the eyes.
- Doodly Typography: Opening the app greets you with a handwritten "TheLight ~ Your Savings Partner" and subtle twinkling stars (✦).
- One Thing at a Time: Four clean tabs (Home, Street, Progress, and Schemes) so you never get overwhelmed by clutter.
- True Laptop & Mobile Ergonomics: On your phone, it’s a smooth, thumb-friendly app. On your laptop, it automatically expands into a wide-screen dashboard with dual analytics and keyboard hotkeys (1–4).
What I Learned Building This
- AWS Serverless Application Model (SAM) is a superpower: Being able to spin up Lambda, API Gateway, Amazon Location indexes, and DynamoDB in a single template.yaml file means you spend 90% of your time building user experience and 10% on plumbing.
- Environmental tech doesn't have to be boring: Saving the planet doesn't require living in a dark cave without lights; it just requires a little bit of smart timing and turning off vampire appliances.
Check It Out!
- Built for: Bharat Builds Tour — Environmental Hacks (Waste and Energy)
- Author: Mahee Tailor
- Live App: Test TheLight Live Demo
Go unplug that idle toaster charger right now, and let me know in the comments: what's the single dumbest thing in your house running up your electric bill? ⚡😄
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