Shift Register - 7seg - power issue?

Hello Im having a interesting power issue with a small project I recently put together. Im still very new to this but cant find any answers searching around..

I have a simple 7 segment led with a (74HC595) shift register hooked up to a adafruit trinket. Im using it as a gear position sensor on a motorcycle. I have a 7805 voltage regulator capactiors 10uf on the unregulated side and 10uf + 0.1uf on the regulated side. to drop the motorcycle 12-14v to 5v to power my project.

When I power the unit up sometimes my 7seg led will light up then go out and stay out, If I cycle the power it will come on and stay on with no issues. Im not sure if the capacitors on the 7805 regulator are maybe creating some sort of initial power up issues and tripping the shift register? Or maybe a solder issue some where but Ive checked and checked.. sometimes it takes a few cycles for it to come on or some small tapping around housing and it will come on, but once you turn it off for a little you have to repeat to get it back on... So im sort of at a loss at the moment any ideas for me Id greatly appreciate it! Thank you


Thank you for sharing your project in Arduino Forum.

I would suggest to check with a voltmeter that all voltages at different points of the circuit are correct. Specially after the capacitors and voltage regulator. It might be obvious thing to do but I can't think on anything else as a first approach.

Also testing the shifting circuit in standalone, using only theoretical values to see if it works as expected. This way we can isolate problems with current peaks that might come from the motorcycle.

I hope this helps!