DIY TalkTimer Keeps Presentations Concise

Public speaking is hard and so most presenters spend a great deal of time preparing their speeches. But even so, it can be difficult to fill an exact amount of time. If the speaker improvises at all, then time management becomes even more difficult. And though there is often some flexibility, conference hosts need to keep the event moving along on track. A friend of wouterrusman’s hosts conferences and confided that they struggle to keep presenters on schedule, so wouterrusman built their friend this DIY TalkTimer.

Event spaces and organizers often have big lights to tell speakers it is time to wrap things up, but this is even better. It displays a countdown, so presenters can see exactly how much time they have left and act accordingly — whether that means talking faster, skipping material, or slowing down to a sedate pace. The user can set the end time and start the countdown through a handy web interface, and the display is large enough for the speaker to see clearly from a distance.

This display has five digits, so it could work for presentations as long as 9 hours, 59 minutes, and 59 seconds — perfect for a politician attempting a filibuster. Each of those digits is a big seven-segment display, with WS2812B individually addressable RGB LEDs illuminating the segments. Those can be set to any color or brightness, which allows for some additional indicators. This requires a total of 109 LEDs: 21 for each digit (three for each segment), plus another four for the two colons.

An ESP32 development board controls those LEDs. To take advantage of the plentiful libraries, wouterrusman programmed the ESP32 using the Arduino IDE. It pulls the current time using NTP (Network Time Protocol) and counts down to the set end time of the current presentation, configurable through a self-hosted web interface. When the countdown first starts, TalkTimer displays the time in white. When 10 minutes remain, it switches to yellow, and then orange when five minutes remain. When no time remains, it turns red.

TalkTimer’s enclosure is wood, with a 3D-printed faceplate designed to accommodate the LED strips. That’s a dual-color print with white segments to diffuse the LEDs. The tutorial doesn’t specify, but we assume that the intention is to place TalkTimer on a table in view of the speaker—though it would certainly be possible to add a mount so it can fit onto standard light stands.