# Advise - Building a flashing puck

**URL:** <https://forum.core-electronics.com.au/t/advise-building-a-flashing-puck/9777>\
**Category:** Uncategorized\
**Created:** [30 March 2021 23:44 UTC](https://forum.core-electronics.com.au/t/advise-building-a-flashing-puck/9777 "2021-03-30T23:44:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Annetta156745](https://avatars.discourse-cdn.com/v4/letter/a/5f8ce5/32.png) [@Annetta156745](https://forum.core-electronics.com.au/u/Annetta156745)\
**Post date:** [30 March 2021 23:44 UTC](https://forum.core-electronics.com.au/t/advise-building-a-flashing-puck/9777/1 "2021-03-30T23:44:16Z")

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Greetings - writing this for my son (13) as he is uncomfortable, hoping this will be a positive encounter for him!  
He is in need of some help/ideas on building a small flashing puck that he is working on for a school technology assignment.  
Approx 30mm dia.  
Micro controller - Trinket Mo? Or ADAFruit trinket  
Sensor - Accelerometer  
Flashing Led  
Battery  
Would love some advise before purchase any further products.  
Apologise if I am in the incorrect category

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**Author:** ![Oliver](https://yyz2.discourse-cdn.com/flex028/user_avatar/forum.core-electronics.com.au/oliver/32/3315_2.png) [@Oliver](https://forum.core-electronics.com.au/u/Oliver)\
**Post date:** [30 March 2021 23:59 UTC](https://forum.core-electronics.com.au/t/advise-building-a-flashing-puck/9777/2 "2021-03-30T23:59:55Z")

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Hi Annetta,

Thanks for making a post! If you had a larger size limit a Circuit Playground Express would be ideal:

> **[Circuit Playground Express](https://core-electronics.com.au/circuit-playground-express-developer-edition.html)**
>
> Circuit Playground Express is the next step towards a perfect introduction to electronics and programming. Adafruit have taken the original Circuit Playground Classic and made it even better! Not only did they pack even more sensors in, They also...

The 30mm diameter requirement will make things tricky to find something with all those features! The [Tinket M0](https://core-electronics.com.au/adafruit-trinket-m0-for-use-with-circuitpython-arduino-ide.html) might be a good choice. Other boards that come to mind are the [Gemma V2](https://core-electronics.com.au/adafruit-gemma-miniature-wearable-electronic-platform.html) which you could combine with something like a FemtoBeacon:

> **[FemtoBeacon](https://www.crowdsupply.com/femto/femtobeacon)**
>
> A tiny, open hardware motion sensor with Wi-Fi & Bluetooth capabilities