Spent the weekend finally dusting off the kit and got my first real build working

That radar sweep servant thing you're planning was almost exactly the route I went when I got my Elegoo kit a couple years back. Mine went the other direction though, I stuck an HC-SR04 on a cheap little servo gimbal I made out of popsicle sticks and hot glue, and had the readings plotted in the Processing app on my laptop. It looked like a submarine screen and I cant tell you how dumb I felt being that proud of it. Still one of my favorite builds though. Fair warning on the servo part, if you power it straight off the Arduino 5V pin it can reset the board when it moves, especially the bigger ones like the MG995 my kit came with. I got around it by feeding the servo its own power and just tying the grounds togehter. Took me a whole frustrating evening to work out why my sensor data kept glitching. Also do the resistor sorting sooner rather than later. I put it off for like a year and every project started with a ten minute argument between me, a color code chart, and my phone flashlight. A little plastic tackle box with adjustable dividers from the hardware store cost me under ten bucks and sorted my whole life out.

After the radar, try the photoresistor for an automatic night light. Dead simple and weirdly satisfying.

I've had one of those big boxes for about three years now and I never built the fancy combined stuff. My path was completley diffrent, one sensor at a time, each on its own little breadboard that never gets taken apart. The photoresistor and an LED became a nightlight for the hallway that's still running off a phone charger two years later. The DHT11 sits on my garage shelf telling me when it's getting damp in there. Nothing impressive to look at but each one does a real job in the house.

The radar sweep builds look amazing but honestly most of us build them once, film it, and never touch them again. A sensor that just quietly does one useful thing every day taught me way more because I had to deal with real problems, like the light sensor reading differently at dusk versus when the kitchen lights were on.

Also on the resistor sorting, grab a cheap plastic organizer with the adjustable compartments instead of a bag. I spent one evening measuring each one with the multimeter and writing the values on tape, best hour I ever spent because now I can actually find a 10k when I need it.

This is encouraging to read because I'm in the exact same spot, drawer full of parts, zero progress until last week. My first win was different though, just got an LED to blink on a timer and I was weirdly proud of that too. Question for anyone who's done the sweep thing, does the code get messy fast when you're reading the sensor and moving the servo at the same time? I tried something similar with two blinking LEDs and my sketch turned into spaghetti almost immediately. Probably just need more practice writing it out properly.

The sweep code stays manageable if you resist the urge to get fancy. I ran a similar setup on my workbench for checking blind spots behind my shed gate, and the whole sketch was under 80 lines. Just move the servo in steps, take one reading per step, print angle and distance on the same line, and let whatever draws the picture handle the rest. The mistake people make is trying to smooth the data in Arduino, do that later on the laptop side if you need to.

One tip for the sweep itself, give the servo a beat to settle before each reading or you'll get smeared numbers at the edges of the arc.

Seconding the nightlight suggestion, that photoresistor is what got my kid intersted in the whole box in the first place. One thing I learned on mine though, add a small delay between readings or the lamp flickers like mad when a car's headlights sweep past the window. Also covered mine with a bit of tape so it only relly notices room light instead of every little change, took a few tries to get the cutoff point where I wanted it.