F1 Style Starting Lights

My wife and I love F1, and we wanted to make something cool for our toddler to play with that was F1 inspired - we came up with the idea of a sequence of red lights that mimic F1 style race-start lights.  Alas, the internet could not produce something out-of-the-box, so it was time to break out OnShape and the 3d printer and DIY it up.  And here it is!

Ultimately it's just a large box with a bunch of strategically placed holes to mount some arduinos and a push button, as well as a lid that has 5 holes in it for 2-inch LED lights.

This is my first arduino project, I mocked it up with an Uno and just ran with it, I recognize that an arduino mini or similar and some mosfets would be better so I could replace the dupont connectors with soldered connections and shrink the electronics a bunch… but it works!

To anyone who wants to build one of these - This is my first time creating something of this complexity myself and publishing it.  I apologize in advance for what I'm sure will be some head-scratching as you try and get it working for yourself - I'm happy to help or answer questions.

Parts List
* 12x - m3x6 heatset inserts
* 11x - m3x4 heatset inserts
* 12x - m3 x 8+ bolts
* 11x - m3 x 8 bolts
* Push botton - https://www.amazon.com/dp/B0CJHXJWN3
* Arduino Uno R3
* Elegoo 8x Relay Shield for Arduino Uno - https://www.amazon.com/ELEGOO-Channel-Optocoupler-Compatible-Raspberry/dp/B09ZQRLD95/
* 2 Inch LED Lights - amazon.com/dp/B0BW99J3K7?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1 

Arduino Code - https://github.com/ZachGoldberg/hobbyprojects/tree/main/f1lights

Onshape link - https://cad.onshape.com/documents/12e3e6dc07c1b888464e5f4d/w/f0a725939976e5c34d18171d/e/9d79bda7e6e97155143afe58

Video of it working - https://photos.app.goo.gl/Jrzdhj5d1NS9gspo8

Implementation Details:

Wiring
I'm using arduino pins 4-9 for the relay signals.  Pin 2 to sense the button.  I'm using a 9v via the barrel jack to power BOTH the ardunio and the actual lights.  Power to the lights is sent from the Vin pin (which is ~0.7v less than the barrel jack voltage, so really 8.3V) on the uno to the individual lights - this isn't an ideal setup, but the lights use about 300mw each at 9v, so its a total of about 1.5W, seems like the Vin pin/traces have no problem with that.  Feel free to do it differently than I did.

Assembly
The whole thing isn't symmetrical because reasons.  So it's five unique parts.  The two bases connect via 3x m3 bolts in the middle, the three lids have bolt holes that only really go together one way.  Line up the holes on top and you can't really mess it up.  Once bolted together it's a remarkably solid unit.

TODO

• Replace ardunio uno with a mini or similar to eliminate all friction-fit connectors
• Re-model the ports in the side so it's a more tailor-made fit 
• Add wall mount affordance
• Add a 9V battery compartment and wiring so it can use 9V internally rather than the external barrel jack