Good approach to gain more usefulness out of the microcontroller version.
Now if you look outside the schematic to the power supply, a 9V battery can be considered ideal for so many demo circuits like this. So there is nothing outside that box unless you wanted to run it on line power or something.
A simple power supply is needed to substitute for a 9V battery, having a stable clean performance ideal for microcontrollers, they are very common and not very expensive but can often actually have more components than the experimental PCB.
On both schematics notice he has a 7805 to reduce & regulate the raw 9V supply anyway.
OTOH there are 555's robust enough to run directly on very poorly filtered & rectified AC line voltage, some of the roughest half-wave. Using only 3 passive components and not even a step-down transformer. Yes it could be quite shocking if you are not careful.
Now if you look outside the schematic to the power supply, a 9V battery can be considered ideal for so many demo circuits like this. So there is nothing outside that box unless you wanted to run it on line power or something.
A simple power supply is needed to substitute for a 9V battery, having a stable clean performance ideal for microcontrollers, they are very common and not very expensive but can often actually have more components than the experimental PCB.
On both schematics notice he has a 7805 to reduce & regulate the raw 9V supply anyway.
OTOH there are 555's robust enough to run directly on very poorly filtered & rectified AC line voltage, some of the roughest half-wave. Using only 3 passive components and not even a step-down transformer. Yes it could be quite shocking if you are not careful.