Climbing Wall Timer

Okay, heres the scoop.

I want to build a digital timer for a climbing wall. The idea is that the moment the climber lifts off the pressure pad the timer starts, it stops when they wack a button at the top of the wall. The time is displayed live on a 7 segment display showing up to a tenth of a second. I want to make the display out of WS2812B strip with each of the segments being 3 pixels wide.

I've been sat here, with very minimal knowledge as it is, trying to figure this out for the last 4 hours... I'm lost!

Could anyone help me?

Thank you :slight_smile:

Could anyone help me?

With what? You have not told us what you are having problems with!

Lmao my bad..I basically have no idea where to start! Any guide to what I need to look into would be great. Any guides, videos etc etc...

Lmao my bad..I basically have no idea where to start! Any guide to what I need to look into would be great. Any guides, videos etc etc...

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  • millis() returns the time in ms since rebooting, unsigned long currentTime = millis();

start with a couple switches and the free exampes in the IDE.

then watch youtube videos and search for the LEDs you chose.

between the two, you will have enough to get started.

As they say so often, start at the beginning.

The basis of what you need cto do can be done with a simple Arduino UNO and a couple of switches.

One switch to start a timer running the other to stop it, no need to worry about 7 segment displays at this point, just print the results to the serial monitor.

Agreed, start with the buttons, and make the timer part work. Print to the Serial monitor first, then when you have that working you can use the output and start driving your display instead.

For the 7-segment part (assuming you don't want to use those LEDs for additional fancy light effects) I'd be using a set of regular 12V LED strips. One strip (or series of strips) per segment. Drive those through a MOSFET and 74HC595 port extender - one 595 and 7 MOSFETs per digit..

It sounds like you want to make the display pretty big. Note that an Arduino can control no more than a couple hundred WS2812B LEDs, and it takes time to write that many of them, possibly enough to upset your 100 ms intervals. You will also run into power supply issues with that many LEDs.

Hi Alan.

Wireless connection between the switches and the Arduino would be neat.


If the switches were wired into the Arduino they don’t have to be two independent switches. They could both be connected to the same input pin on the Arduino. Stepping off the pressure plate would open the circuit, hitting the button at the top of the wall would close the circuit.

They could be connected to an Arduino with Bluetooth which would connect to a phone or tablet.

A tablet could also do the job of displaying the time.

each of the segments being 3 pixels wide.

Did you mean "long"?

Assuming you did, you might find ws2811 strips a little cheaper than ws2812. They are generally 12V rather than 5V, and you can only cut the strip after each group of 3 leds, but that won't be a problem in your case.

I would recommend ws2811/2 over regular led strips, shift registers and mosfets, to keep the circuit simple.

Some "don'ts": Don't buy an Uno or Mega. So many beginners make that mistake. Just get a Nano, and use the saving to buy a larger breadboard. Don't get a starter kit, they are full of junk. Don't get dupont cables, they are unreliable. Use solid-core wire, you can buy packs with a metre each of a few different colours.

Wireless doorbells.

Very cheap.