sports timer improvement project

Hello, :blush:

I belong to a Kendo club in France.
We bought a timer to pace our sessions.

Unfortunately, the sound of the round start and end beeps is too quiet for everyone to hear.
I’d like to improve this without modifying the timer.
The idea is as follows:
I would like to:
1 - Detect the word “work” on the display using a light-sensitive sensor and play an MP3 file on a speaker via Bluetooth.
2 - Detect the word “rest” on the display using a light-sensitive sensor and play an MP3 file on a speaker via Bluetooth. I thought about using this module:

My questions:
1 - Can we connect two photosensitive sensors to this module?
2 - Can we transmit to a Bluetooth speaker?

Thanks for your advice. :person_bowing:

  1. Yes, although you’d need to mount the photo-resistive sensors VERY close to the display for them to work as you’ve described

  2. Yes, that board has BT and you can pass audio using it:-)

You also might want to look at using an amp if the speaker is large, something like SparkFun Qwiic Speaker Amp - SparkFun Electronics

If you have an arduino laying around you could also take a look at WAV Trigger - SparkFun Electronics

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Good evening.

Thank you for your advice. :person_bowing:

I’ll stick with my initial choice. It’ll be simpler.

I’m going to transmit to an 80-watt connected speaker. I don’t think I’ll need an amplifier.

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Do you have a link to a document explaining how to program this card? A tutorial perhaps?

I think you might actually be able to get something to work with just the photo sensors if you still want to give it a try. The display does appear to have big, well-separated Work / Rest lights and I think you could read them without even opening (tampering?) the timer case and by simply temporarily applying sensor(s) over the front.


Have some fun with it. I’m picturing an old 70’s night light, the 1 Watt incand bulb one in granny’s bathroom still working after all these years, with the sensor side taped to the timer, monitoring the Rest light. The Timer Official starts the clock and sets the alarm, a weak electromagnet in place of the bulb and holding a steel cowbell. When Rest rises in the East, the night light powers down and the cowbell clatters to the ground. Elegant!

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I actually want to place the sensors in front of the timer. I don’t want to open it and damage it. I’m not an Arduino board expert, but I’ll do my best. I wouldn’t mind some help if I’m having too much trouble.

We have this guide for the photocells and this one for the esp32 IoT Redboard :slight_smile:

Thank you. I will receive the card at the end of the week.

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