How / where / from whom / how to learn applied circuitry (it's hard to specify, read the question)?

Question

Electronics

Hello. In the university there is a circuit engineering subject. I did everything on my own, but I never applied or saw anything in practice in my life. Before this semester, there were just tasks, like drawing an adder, designing a trigger, calculating the voltage (s) on the circuit. In general, Ohm's law and digital circuitry. And then such a sharp transition :) They gave me a course paper, I chose the simplest one, focusing on the name: a backlit photo frame. It turned out that the brightness of the backlight should change depending on the distance at which the person approached. And the backlight should work autonomously for a month (but here they probably won’t find fault much, let alone check).
When giving out the topic, the teacher said that the frame should glow for a long time, and because. Arduino is too expensive, you need to use MEGA8 (I think so). Need some kind of distance sensors, LEDs, battery... . Bought a distance sensor.
I never made anything at all, except for labor lessons (the last time I sculpted from plasticine). About Arduino, MEGA8 heard for the first time.
There is knowledge of Ohm's laws, discrete mathematics and digital circuitry. Where to start, what to do? Maybe there are some books, sites dedicated to this case?

Answer 1

>> should work autonomously for a month (but here they probably won’t find fault much, let alone check).
In real life it is necessary to prove it (course, however!). At least it's stupid to divide the battery capacity by the current consumed. ATMEGA8 consumes 3.5mA (I don’t remember exactly, see the datasheet) i.e. you only need 30 * 24 * 3.5 = 2600mAh for the MK, plus more LEDs. It is necessary to smoke the topics "energy saving mode" and "Watchdog timer" to reduce current consumption by at least 1.5 times, then it will be possible to power the circuit with a pair of Chinese lithium batteries
>> Arduino is too expensive, you need to use MEGA8
The difference in price is a maximum of 2 times, but ATMEGA8 is a bare chip that requires strapping, and Arduino is a ready-made device that can be used as is. In addition, Arduino is incommensurably easier to program than an independent MK. So you won’t save much, but there will be plenty of hemorrhoids on your head. I think you have enough, for example, Digispark Attiny 85 , although a beginner is better off with Arduino NANO V 3.0 CH340G
As for the distance sensor. They are ultrasonic, infrared and laser. We discard laser ones unequivocally because of the space cost. IRs do not work very accurately and at short distances up to 1.5m, ultrasound is more accurate and works up to 5m, but a person usually walks in soft, sound-absorbing clothes, so the ultrasound sensor may not "see" him
PS You can also consider another option. I can write you the technical part of the course book, tell you in detail what to get and where, under my strict guidance, you will assemble your frame

Answer 2

In practice / at home / at the Internet / analytical thinking of the brain.

Answer 3

Well, all this can be implemented on arduino. I just don't understand how expensive it is. on aliexpress 300 r costs. and there you can find all the sensors and everything your heart desires. also on arduino just a lot of guides and video tutorials.

Answer 4

It seems that the consumption of the 328th mega was understood as "costly".

Answer 5

Of the distance sensors, I can add there is also a microwave that behaves very well and if I'm not mistaken, it's about 15 meters. And in vain you dismiss a huge amount of arduino literature, there are a lot of sketches, plus your good compiler (try Google), you can work less with a soldering iron indefinitely, you can describe all the pluses of an arduino. Dare, this electronics is an interesting thing!