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Topic: Sail regatta countdown timer (Read 471 times) previous topic - next topic


Hi I am fairly new to arduino but i would like to make a (waterproof)countdown timer for my local sailing club. I would like the following functions:

- countdown from 5 min
- giving a 2 second horn blast at: 5 min, 4 min, 1 min and 0 min
- buzzing (buzzer on arduino) 0,5 sec at 10 seconds to the min, buzzing every second
- being able to change the starting time (for instance 3 min)
- being able to sound the horn with a separate button (after the sequence, but if possible also during)
- displaying the remaining time

I have the following supplies:
- arduino nano
- TM1637 LED Display Module For Arduino 7 Segment 4 Bits 0.36 Inch Clock RED Anode Digital Tube Four Serial Driver Board Pack
- 12v horn
- 5v buzzer
- 12v battery
- real time clock module
- 5v low level relay
- momentary push buttons

What do i need to buy to make this project and can somebody help me with the code?

I hope somebody can help me.


By "help" do you mean you want to pay someone to write your code? Otherwise you might find more help in the Project Guidance forum.

BTW: I've found the TM1637 library to be buggy.
Electronics and firmware/software design and assistance. No project too small


Well i am a college student and this is just a fun project for me so i don't want to spend (to much) money on it. How much would a code like this cost? Would you advise another time counting methode?



Apr 14, 2019, 06:32 pm Last Edit: Apr 14, 2019, 06:34 pm by cedarlakeinstruments
Not passing judgement here, but I don't see how you can view it as a "fun project" if someone is building it for you, but whatever.

This timer looks like it'll do what you need except for the horn blast and it's pretty cheap. Less than I'd charge to do the job anyway.
Electronics and firmware/software design and assistance. No project too small


It looks like you have done some research. If you want to hire someone and want to make the best use of your money, you could do a little more work.

Take you list of parts and make a list of pins. Each button and relay and LED gets one. Read the data sheets for the timer and display.

Review the list an make sure you haven't forgotten anything. Give every component that connects to an IO port a name. It would be helpful to make the list to like this:


The use of uppercase and underscores is a convention in programming to indicate a constant. Using the suffix PIN makes the code much easier to read.

Now take you list of features and turn it into a user's manual. Say things like to start the device press the Start Button ( have you included a start button, toggle switch, ...? ).

To set the timer, press Set and then, ... Each step in the user's instructions must correspond to a component with a name you gave it above.

Once you have completed these steps, you have a basis for development. There are two paths from there:

1. You hand all you have written to a programmer and agree to pay that person to setup an Arduino with the parts on a breadboard and develop the sketch. Be prepared to pay hundreds of dollars, maybe thousands. The costs depends on the amount of time the programmer will need to spend on the project. The amount of time the programmer needs to spend depends on the quality of your user's manual-the more successful you are at envisioning the product, the better things will go.

2. You learn to program and do the work, seeking advice on this forum.

If you pick 2. The next step is to start connecting things. Get a solderless breadboard, one that is bigger than you think you may need. Pay $20-$40 for it.

Learn how to read the pushbuttons and light LEDs and proceed to more complex parts.

Once you have accomplished 1&2, you can hire someone to make the PCB and the watertight container. That may be two people.

Enjoy your new adventure.

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