Postal Parcel Scale Kit with ESP32 + LED
Track Inventory Weight and Auto-Reorder with This ESP32 Postal Scale
Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.
Place this scale under your supply bins, and it quietly measures the combined weight of hundreds of parcels, envelopes, or components. The ESP32 calculates how many are left based on a calibrated unit weight, logs every change to an SD card with an RTC timestamp, and fires a reorder alert when stock drops below your preset threshold. No barcode scans, no manual counts — just a live inventory count that keeps pace with daily dispatches.
What You'll Build
You'll build a four‑container weight‑monitoring station that sits on any shelf or counter. Each HX711‑paired load cell senses the weight of a container; the ESP32 converts that reading into an estimated quantity, displays real‑time status on the OLED, and writes a dated log to the microSD. The moment a bin needs refilling, the microcontroller pushes a webhook that can send you a WhatsApp ping, an email, or light an LED on the box — keeping your fulfilment or fabrication line running without a single stockout.
What You'll Learn
- Calibrating four HX711 load cells with ESP32 for repeatable sub‑gram accuracy
- Integrating the DS3231 real‑time clock to timestamp every weight reading
- Setting up auto‑reorder webhooks and parsing HTTP responses over WiFi
- Designing a permanent SMD/through‑hole prototype on PCB and fitting it into an enclosure
Kit Contents
| Component | Quantity |
|---|---|
| ESP32 Dev Board | 1 |
| HX711 | 4 |
| 1kg Load Cell | 4 |
| DS3231 RTC | 1 |
| MicroSD Module | 1 |
| 0.96in OLED | 1 |
| LM2596 Buck Converter | 1 |
| 100nF Caps | 10 |
| 4.7kΩ Resistors | 5 |
| PCB Prototype Board | 2 |
| Enclosure Box | 1 |
| 5V 2A PSU | 1 |
| Soldering Iron | 1 |
| Solder Wire | 1 |
Why Buy This Kit Instead of Sourcing Parts Separately
| Factor | Sourcing Separately | Compoden Kit |
|---|---|---|
| Compatibility checks | You verify every part | Pre-tested as a system |
| Build support | Forums and scattered tutorials | AI companion trained on this exact project |
| Time to first working build | Days of debugging | Hours, with step-by-step guidance |
| Shipping coordination | Multiple sellers, multiple delays | One shipment from Bengaluru in 3-5 days |
Who This Kit Is For
This kit is built for India’s warehouse operators, small e‑commerce packers, and components distributors who need to keep bins full without a full ERP. B.Tech ECE and EEE students prototyping supply‑chain IoT for Smart India Hackathon will find a ready‑to‑integrate hardware stack. Even advanced makers running home labs or ATL Tinkering mentors can use it to teach real‑time inventory logic.
Built and Backed by Compoden
Every Compoden kit ships with an AI build companion trained on this exact project — accessible via a QR code on the box, with WhatsApp and email backup. We've spent 10 years building projects for makers, schools, and institutions across India. If a part fails because of a manufacturing defect, replace it free within 7 days.
What if I get stuck during the build?
Scan the QR code inside the box or WhatsApp us — our AI companion gives immediate step‑by‑step guidance, and a senior maker will jump in if you still need help.
Can I monitor more than four containers?
Yes. The ESP32 can chain additional HX711 boards on the same I²C bus, but you’ll need to modify the firmware and supply extra power. The build companion covers expansion details.
How does the reorder alert actually notify me?
The ESP32 sends a webhook to a service of your choice — IFTTT, Pushover, or a custom Telegram bot. You can receive an email, app notification, or even trigger a physical LED in your workspace.
Can this kit weigh very light items like SMD resistors?
Absolutely. The 1 kg load cells with HX711 provide milligram‑level sensitivity after proper calibration, letting you count tiny components by weight with surprising accuracy.
Logistics — HX711 load cells under containers track weight. ESP32 estimates quantity remaining and triggers reorder alert.
What's in this kit
Choose your assembly option:
- Soldering Kit — 25W soldering iron, 60/40 solder wire, flux, and small perfboard for permanent assembly.
- Breadboard Combo — 800-point full-size breadboard with 65-piece jumper wire pack for solderless prototyping.
Other projects you can build
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items