12 Nov
2022
12 Nov
'22
5:26 p.m.
On Sat, Nov 12, 2022 at 10:28:09AM +0000, Tony Duell via cctalk wrote:
[...]
The other day I saw a product with a flashing LED, the
flash rate was set
with a knob. Yes, a microcontroller with a pot connected to an analogue
input and LED hung off an output port. This is the sort of thing I'd do
with a couple of transistors or an NE555 depending on which turned up in
the junk box first.
Farnell Nederland is quoting me €1.06 (+21% VAT) for the cheapest brand of
555 in stock. Their search won't let me find the cheapest microcontroller
without drilling down further, but an 8 pin AVR is €0.88. That's single item
quantities in DIP packaging, as is typical for small home projects. The 555
will also need a capacitor for its RC timer circuit which is another few
tens of cents. And that's why people use microcontrollers to blink LEDs.
The MCU in the Pi Pico is also well under a euro if you buy a reel of 3,400
of them. That's probably a few too many for an average hobbyist :)