← Back to portfolio Version 2.0 · always evolving

Control Key

Name: Control Key
Author: CalbarTech

Who took which key, and when. All on a tablet.

I want Control Key → See what’s new

01 / The story

From a paper notebook to version 2.0.

While you read, the TV alongsidejust below tells how it happened — from the first sketch to today. (App screens are in Portuguese.)

Ch. 1

The problem

It all started with a key cabinet tracked on paper. Who took it? Since when? Was it returned? Nobody knew for sure — and “has anyone seen the key to room 12?” was a daily question.
Ch. 2

The idea

The idea was simple: a tablet mounted next to the cabinet. Each key becomes a number on screen; whoever takes one taps it, picks their own name and that’s it. We started with 40 keys — soon it was 50.
Ch. 3

First draft

The first draft went straight to the point: green means the key is in the cabinet, red means it’s out. Tap a free key: category → name → confirmation. Tap a key that’s out: return it or take it over (transfer) — and if someone forgot to return it, that gets logged.

Screens recreated from the original code (in Portuguese).
Ch. 4

v1.0 is born

With a name, a splash screen and an Admin area (categories, team members and Excel export), v1.0 was born. “Employee” became “Team member”. And the real test happened on an actual tablet and phone.
Ch. 5

Behind the scenes: what went wrong and how we fixed it

Not everything worked the first time — and that’s okay. Data that wouldn’t save, a password that wouldn’t confirm with Enter, an adjustment for the tablet’s Android 13, and even the tablet’s security system blocking the install (IT approved it). Every bug became a lesson.
Ch. 6

Ideas we kept and ideas we cut
- Spare key: every number got a main and a spare — the square split “corner to corner”.
- Neon halo around the key and keychain color, to find it faster.
- Banner listing keys on the idle screen → became something better: who has which key, and since when.
- Color categories with authorization → became the keychain color (and, in 2.0, the department color).
Ch. 7

v1.2: clearer in the rush

v1.2 brought a new home screen (who has each key and since when), closed/open locks on the grid, confirmation with the key name, date and time, the forgotten-return notice and an Admin area with its own password and automatic backups.
Ch. 8

The first sale asks for more

The first sale was to the front desk of an industrial plant, with lots of traffic. Listening to the people who use it every day changed everything: color-coded departments, guards and shift changes, voice entry, undo, organized visitors, cabinet labels and a log of every change.
Ch. 9

Today: v2.0, always evolving

Today Control Key is on version 2.0 — and it keeps evolving with every conversation with the people who use it. Right below, everything it does now. 👇

2 minto set up
200keys per tablet
100%offline day to day
10keys for free

02 / What’s new in 2.0

Built so the front desk never stalls.

Fewer taps for whoever hands out the keys. More control for whoever runs the company.

Home screen

Who has which key, at a glance.

The idle screen shows only the keys that are out: who took them, from which department and how long ago. Search by person, number or place — even by voice — and filter by department in one tap.

Keys-out counter always on screen
Visitors clearly tagged
Guard on duty and next shift change at the top

Home screen with keys out, department filters and Visitor, Employee and Select key buttons

Departments and colors

Every department has its color. The whole cabinet in one grid.

Production, HR, Maintenance, Shipping… each department gets a color, and the grid instantly shows what’s in the cabinet, what’s out and what’s under maintenance — with hooks for main and spare keys.

Up to 200 keys per tablet
Color-blind mode: each department also gets a shape

Grid of color-coded keys with main and spare hooks and status legend

Voice entry

“Maria Souza, key 12.” Done.

A visitor just arrived? Tap the mic and say the name and the key. Control Key fills in the form and the key goes out in seconds — no typing in a rush.

Confirmation + undo

Wrong tap? Undo it right away.

Every pickup confirms with a sound and shows place, type, date, time and who handed it out. If you tapped the wrong thing, an “Undo” button stays on screen for a few seconds — and it all goes into the log.

Pickup confirmation with an Undo button counting down

Guards and shift changes

Shift changes remind themselves.

Add your guards and when each shift starts. The app warns before the change, asks afterwards if nobody switched, and at handover shows the keys still out from the previous shift.

Subtle banner 30 min before
Pop-up 30 min after, if nobody switched
“It’s me, I’m staying” logs the overtime

The three moments of a shift change: reminder before, alert after and choosing who takes over

Admin

Every change, with a name and a time.

The change log shows who added, deleted, undid or took over a shift. Admin also clears unused visitors automatically and flags people the front desk added that need review.