60 Seconds Timer for Shooting Range

This 60-second timer is always in the competitive shooter’s sights.

Among the shooting disciplines of the German Shooting Sports Union (DSU) are the so-called K20-K23 handgun events.

In these events, a series of 18 shots must be fired at the corresponding target.

As a sport shooter, the challenge lies in managing your time: if you’re too fast, it can lead to missed shots; if you’re too slow, the event may end before you’ve fired all your shots. Shouts from the crowd are distracting, and a large digital timer display can impair concentration.

That’s why I decided to build and program a countdown timer in the form of an “hourglass.” This “hourglass,” which runs horizontally, is positioned about 1.5–2 meters in front of the shooter, just within the shooter’s peripheral vision.

It displays a window approximately 160 cm wide and 90 mm high, which starts out white and gradually turns completely red as the countdown progresses. Once the time has elapsed, the system waits a few seconds before returning to its home position.

An LED glows GREEN for the entire 60 seconds, whereas a RED LED is normally lit. After startup, the red LED flashes 5 times (5 seconds), and at the same time, an active beeper beeps in sync. After the 5 seconds, only the green LED remains lit, accompanying the shooting process for 60 seconds. If the beeping is annoying, you can also turn off the beeper using a pushbutton.

An additional start option is planned, though it hasn’t been fully worked out yet: A powerful LED flashlight can be used to shine light on a light sensor (photo resistor), which, when exposed to a certain level of light, triggers the process just like the start button. Before we optimize this further, we first need to confirm the usability of the 60-second timer.

Let’s see if this timer can help us manage our time better for these disciplines.

Designed in TinkerCad.

Mostly printed on my MK4 and Sovol SV08.

Powered by 3S-LiIon with 3S-BMS. All are standard components for Ali or Amazon.

Some crucial purchase parts:

• GT2-belt 500mm
• GT2-belt 158teeth
• MT3608 Step up/down: 3S LiIon in, 12V out
• Hall Sensor K030
• PhotoResistor K018, maybe 4Pin DI anAO / DO is better?
• StepperDriver TD6600 (I hate A4988 and DRV 8825)
• Arduino Nano and Screw-Shield
• LEDs
• Pushbuttons
• Nema17
• 20teeth pulley
• DuPontcrimp contacts
• ø5 dowel
• M8 rod (M8x60 up to 80mmlong) and nuts and washers
• ball bearing 608
• 3 x ball bearing 605
• fasteners, selfthreading fasteners, M3, M4 screws and nuts

Sorry when something is missing or wrong defined. Don't expect a 100% BOM. I am happy my machine is running as I expected. Cost me a lot of time.

Though, happy printing.

Explore my other Printables: https://www.printables.com/de/@Tritschi

Printables Tags: kk; shooting; 22lr; k20; k22; kleinkaliber; schiesssport; k21; k23; dsu