1024 points of soldering !!

Wasn't expecting that when I began, but it's quite interesting and the result will look amazing ^^
I'm making a LED matrix from 0, controlled by an Arduino, it will look really good when it's finished, I plan to use it to display notifications, clock, sound spectrum etc...
What do you think of it ? 😇

Finally, the jeezless present is done.. fuck this shit, where's my booze and my bed?! 😒

Anyway, it's essentially a power bank with LED's attached to it. The LED matrix is at the back side and looks reasonably decent (but I don't wanna disclose the age it's displaying). It's powered through a 47ohm resistor and is directly attached to the 5V lines. Yellow LED's with 2V voltage drop that have each number completely parallelized, and then those numbers are put in series to increase the combined forward voltage of the LED's to 4V. That way the circuit is around 80% efficient (resistor drops 1V, LED's drop the remaining 4V). Other than that, nothing too special. It did take 2 nights to build though.. way too much for a mere formality 😑

So technical interview today but woke up (6am) and started thinking about it and it led to this rant about algorithms. This is probably going into a Medium post if I ever get around to finishing it but sort of just wanted to share the rant that literally just went off in my mind.

*The problem with Algorithms Technical Interviews Is They don't test Real skills*

Real world problems are complex and often cross domain combining experience in multiple areas. Often the best way is not obvious unless you're a polymath and familiar with different areas, paradigms, designs. And intuitively can understand, reason, and combine them.

I don't think this is something a specific algorithm problem is designed to show. And the problem is the optimal solution to some of these and to algorithm design itself is that unless you train for it or are an algorithm designer (practice and experience), you can only brute force it in the amount of time given.

And quite frankly the algorithms I think we rely on daily weren't thought of in 30 minutes. The designers did this stuff for a living, thought about these problems for days and several iterations… at least. A lot were mathematicians. The matrix algorithm that had a Big O of 7N required a flash of insight that only someone constantly looking and thinking about the equations could see.

TBA
-system design
-clean readable coding practices
...

TLDR: I could probably go on and on about this stuff for hours jumping from item/example/area to the next and back again... But I don't think you can test these (~20) years of experience in a 1 hr technical interview focused on algorithms...

#arduino #led matrix
Hey guys.
So, this is my first led matrix using a 74hc595n, I did all the connections right, isolated the cathodes (-), and when I tested, I only connected one cathode (to test one row, when almost all the lights turned on, in all rows doing a chacing... So I disconnected the negative wire and it still works.
One led in the arduino blinks (L).
GND is only connected to the shift register
All the rows light up doing a colum chase when there is no negative.
I'm astowned.....

Hey guys, my gf and I want to do something with the Arduino we got. We are getting a CS degree, so programming is not a problem, but we have quite basic knowledge of electronics.

What could be a cool simple (but not too introductory) project we could do?

The arduino came with a bunch of sensors (ultrasonic distance sensor, humidity, ...) some input (joystick, RFID reader/writer, buttons) and some outputs (LCD display, 8x8 LED matrix, bunch of color and RGB leds).

finish this LED matrix x)