Sparkfun FTDI Basic into a 5V Voltage Regulator

Projects General Guidance
1

Hello,

I'm trying to prep a circuit for PCB, and I want to run it on ATTiny85. The application is to control a 12v solenoid valve via serial input. I've done plenty of Arduino prototyping, and my Arduino Uno prototype works fine, but I'm trying to step up my game with this project. However, the first PCB I received doesn't work and I think it's due to the way I'm routing VCC on FTDI breakout board from Sparkfun. Here is an image of the Fritzing breadboard view, a closeup of what I believe is the problem area, and the schematic. My hunch is that I should not be routing VCC from the breakout to the out pin of the voltage regulator, but can anyone give me some advice? Thanks!

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2

You have absolutely no supply decoupling on that circuit, that alone will ensure it doesn't work.

3

Is the FTDI supposed to be a permanently attached part of your circuit, or just for programming?

4

Permanent. The idea is to send serial data to the ATTiny via the breakout board.

5

No supply decoupling...Does that mean that I should run 12v to the solenoid, remove the regulator, and run VCC from the FTDI to the ATTiny?

6

joshbg2k:
No supply decoupling...Does that mean that I should run 12v to the solenoid, remove the regulator, and run VCC from the FTDI to the ATTiny?

no, he means you need to filter out noise...

https://learn.sparkfun.com/tutorials/capacitors/application-examples

not having decoupling capacitors on the power regulator makes its voltage fluctuate...

7

Ok thanks everyone I see what you mean. One last question - should VCC on the FTDI be routed to the IN or OUT pin of the regulator?