#Guy magnet

An embedded automation programmer goes home and fixes appliances for the village elderly for free. 1) Rice cooker: the light flashing on the repair socket means a loose connection, just push it in firmly; boil water to test the response, water temperature rising from 35°C, heating ring at 100-plus, one done. 2) Hair dryer: no response from the switch, so the switch is suspect; two screws out, it has been opened before and the switch tied with string; multimeter on continuity, the switch pressed shows no continuity; the switch clip is broken, inside is a copper leaf + latch + spring, the two contacts on the copper leaf are burnt, and a diode is wired in for the speed change; no such switch on hand, so the burnt parts of the contacts are cleaned and it goes back, fixed with strong glue instead of string; gear one and two latch fine; the original soldering was sloppy — joints must be solid or they arc, and an arc at the grip is dangerous; suggest a varistor in series across the switch input / output; powered up, back to full health. 3) Cordless drill battery bay won’t charge: odd screws, swap the bit; barely charges and the gauge drops on one press, most likely the cells need replacing; 5S, 21V at full charge; when removing the BMS mind the 4 balance leads; clean off the old nickel, keep the holder; originally 1500mAh each, replaced with 5 new 2000mAh cells with 3C certification; measure every cell’s internal resistance before fitting, this batch all around 17mΩ, fine for a Li-ion drill’s power needs; the original had no fish paper but a ring is best, the 18650 shorts most easily right at that ring; in series order, spot-weld the series nickel strips first, then the main + and − strips, last the balance leads; refit the BMS, tin with the iron and solder the balance-lead nickel strips to the board, connect the main + and − last; check for cold joints; fish paper back on, into the battery bay, screws in; the red charge light is normal, the drill pulls hard. 4) Two membrane keyboards merged into one: swap the cable, note the wire order and numbers, the membrane contacts must line up with the board and be pressed with the clamp bar, cable into its slot, add heat-shrink. 5) Hair dryer plug with one long and one short pin: fit a rice-cooker cord, high power so tin the joints to avoid heating, wrap in tape and heat-shrink. Sign-off: night view of the mountain hollow, ‘maybe I can’t make my hometown rich, but I can contribute a little with what I’ve learned’. 260 comments: five cells out of your own pocket, don’t do this kind of job again (3) → creator: lost my shirt; suggest more close-ups (screws, soldering, multimeter readings) → noted; hold the iron by the grip (proper practice); serving the people, down to earth; that workbench is my dream → I’ll make one.

Somehow ended up making a few fun color-changing night lights / mood lights as a gift for the students who took a term of the science maker extension class — a little present for the last lesson, tied to what we covered. Simple parts: a cell, a charge-management module, a switch and a color-changing LED bead; the LED draws only 0.01A, so one 2000mAh 18650 keeps it lit for a month; the goals were long runtime, fun color changing, durable, rechargeable, simple and cheap to make. Build: nickel strip is already welded to the cell’s +/−; fold the strip over so it doesn’t stick out, and a wrap of tape around the outside makes it more secure; the cell’s +/− go to the charge-management module, charged over a Type-C cable, the module charges the cell at 4.2V; the module’s 5V output goes to the +/− leads; the LED negative goes straight to the output lead, the switch sits on the positive side; test lit fine, decent brightness; loose parts look untidy, so model a shell, one print run of three sets takes over 4 hours; the two halves fit together seamlessly; three done (short on time). Over hills and around eighteen bends to the school; in class every student gets hands-on, small hands not yet skilled but earnest, helping each other, completing the circuit together and lighting their first light-controlled lamp; maybe one day this light will shine among the stars; the lights he made go to the best students; applause closes the last lesson. Comments (143): where to buy such a low-power LED, link? (5); Biao, when’s the next spot-welder sponsorship (why?); a cell must have a BMS, safety first / no BMS, aren’t you afraid the kids get blown up (creator replied); the charging port sits too low to plug in easily; a white shell would diffuse the light better; what brand of multimeter (ALIENTEK); how’s the welder / how much.

Boss, can you give a link for the spot welder

Xiao Zhao takes an order: make me a Dongcheng battery, 20V with 2000 cells, deliver to the 23rd floor when done. Grab purple-wrapped cells and a yellow holder, spot weld (DA DA DA), case it; labelling: no label looks unprofessional, ‘let’s get professional’, stick on the 20V (20Ah) label, now it looks the part; 130 (yuan), little sister takes the battery up to the 23rd floor; the square impact socket set goes to one side; her e-scooter dies one block out and she pushes it back, call a courier? how much can this order make and we’d hire a courier; take my car, petrol costs more than a courier; ours is electric, no petrol, just bought from Guazi Used Cars for only 99k (placement: official inspection, OEM warranty on the three electric systems, 100-day battery-degradation guarantee); a scatterbrained day, this family would fall apart without me. Another battery ‘this one’s no good now’, put back as it was, 80; done, 50. Sister comes back, the car’s in nice shape. Imported STIHL 381 chainsaw: an old sawyer managed to fit the chain backwards; won’t start, swap one; too much oil too, not turning so look at the brushes, rotor isn’t great; 10 yuan; screws all gone makes it easy, pull the battery first; 5 yuan; the all-rounder, 10 yuan, take it slow. 1812 comments: fix this for me (150), Bosch drill burned drilling steel, can I mail it in (99), you dare let sister deliver, not afraid it goes dark (37), they asked for 20V and what’s yours (2, about the 20V20Ah label); how big can a Metabo 18V go.

A customer wants a battery for his newly bought bait launcher; the original battery is dead. The shop owner digs out a similar cell — “not sure it’ll work” — and builds a pack on the spot: insulate as well as possible, wrap another layer of heat-shrink, then one size bigger, safety first; the heat-shrink is a bit large but works; plugged back into the launcher, switch on, works, “that’s it”, call it ¥50. After that: the customer’s drill isn’t working because the bit is too worn to grip; an angle grinder opened up with not a single bearing ball left and the grease dried solid; a pile of tools for repair, one by one: gears to one side, seals to one side, no power to one side, screws all gone to one side, impact jammed to one side, nothing wrong to one side; when fixing an angle grinder the wheel can shatter all over you, wear goggles; quotes ¥25/20/10/15, “jackpot”; eat the fan’s food first; swap the customer’s ratchet chuck for ¥15, the drill is a write-off. 33k comments: top comment “the boss as customers see him”, 480k; four 18650s plus a board and labor for only ¥50, make me two; is ¥15 for a ratchet chuck even enough for the part; the factory battery may not be as good as the one you made.

I’ve figured the internet out — whatever you want to watch I’ll make it for you, ‘but not that one’. First the power bank: make a 9600 (mAh) one, charge it up; I’ll use my own nickel strip; basically done; they don’t even give you fish paper, use this instead; do the cushioning first; real materials; power on, try charging, try discharging, done, and not bad looking, sis, you get a discount. Starts fine but the chain isn’t cutting fast — chain off, really hard to get off, way too much material removed, mind the chain tension, ¥5; a drill that won’t turn, oil coming out (singing); find a screw, charging for the screw and the gloves isn’t unreasonable, ¥5; another one won’t turn, the wire is spliced, snip a section, wire is bad; brute-force it in; a special tool for taking the blade off, ¥15; done. Comments: list of Douyin’s 6 great logistics organizations (4421 likes); petition of ten thousand to see the tree at the door (3161, ‘I said no’); can this be fixed, it keeps saying wrong password (249); which store sells genuine 18650s; welder link / brand; how much for the power bank.

A customer’s hot-glue gun lights up but won’t heat; open it, a wire has come off, stick it back, nothing wrong. Another wants a battery ‘delivered to Hanlin Huafu’ and asks whether to use an original or have me build one — ‘whichever works’; take 15 cells, open the cover, beautiful; measure a single cell at 395 (3.95V); pack assembled, done, ¥130. Then: a stripped screw inside a drill, apply some tricks (scorching hot; I have a way to fix it, done in the open, no secrets); an angle grinder won’t turn, the carbon brushes are worn, and the breaker tripped again (protecting the motor); another one also brushes and a broken wire, brushes are aftermarket not original; bearings are all gone, housing ¥40, bearings ¥10, swap in 607 and 608 bearings; ¥10 each. 9339 comments: top comment ‘original battery or one I make’ at 240k; ‘original isn’t as good as hand-built’; experienced viewers advise not to stick paper on the cell sides (absorbs water), use PET; someone asks whether the assembled pack can be recharged.