DIY an ultra-long-runtime seven-color night light? For the last science maker class of the term, I hand-built an ultra-long-runtime seven-color night light as a gift for my students
Creator’s own settings as stated in the video (timestamps link to the moment). Not official values — test on scrap first.
Bill of materials
Welder, accessories, consumables and parts used in this build; quantities and specs are editable Download BOMDescription
Abiao builds color-changing night lights for his students (2222 likes): one 2000mAh 18650 + charge-management module (Type-C, 4.2V charge, 5V output) + switch + 0.01A color-changing LED, runs a month; nickel strip welded to +/− and folded flat, tape to secure; modeled and 3D-printed shells, three sets in 4 hours; given to the best students in the last maker class of the term; comments: no BMS, aren’t you afraid the kids blow it up? link for the LED?
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.
Outcome
| Goal | Ultra-long-runtime seven-color night lights ×3 for students |
| Build | 1 × 18650 2000mAh + charge-management module + switch + color-changing LED + 3D-printed shell |
| Result | Three finished and given out in class · verified on camera: Lit test at 115–117s; done at 154s; given out at 203–208s |
Steps5 steps · click a frame to jump
1. Origin and design: cell + charge-management module + switch + 0.01A color-changing LED, runs a monthA little gift for the students, tied to the lessons; parts: cell, charge-management module, switch, color-changing LED bead; 0.01A draw, a 2000mAh 18650 lasts a month; long runtime, fun and durable, rechargeable, simple and cheap.
00:00 – 00:46
2. Weld strip to the cell, fold flat, secure with tapeStrip already welded to the cell’s +/−; fold the strip over so it doesn’t stick out; a wrap of tape around the outside makes it more secure.
00:54 – 01:06
3. Connect the charge-management module (Type-C, 4.2V charge); 5V output to the LED, switch on the positiveCell +/− to the charge-management module; Type-C charging, the module gives the cell 4.2V; the module’s 5V output to the +/− leads; the LED negative straight to the output lead; the switch on the positive lead.
01:13 – 01:45
4. Lit test; model and print shells, three sets in 4 hours; seamless fit; made threeLights up fine with decent brightness, works as a seven-color mood light; loose parts look untidy, so model a shell, one print run of three sets takes over 4 hours; the two halves fit seamlessly; short on time, made three.
01:55 – 02:40
5. Over the hills to school; students light their first lamp hands-on; given to the best studentsFrom the village to the school over hills and eighteen bends; in class every student gets hands-on, small hands unskilled but earnest, helping each other to finish the circuit and light their first light-controlled lamp; maybe it will shine among the stars one day; given to the best students; applause closes the last lesson.
02:40 – 03:53
Bill of materials
| 18650 cell ×1 | 2000mAh · Power |
| Charge-management module ×1 | Type-C, 4.2V charge, 5V out · Charging / output |
| Color-changing LED bead ×1 | 0.01A · Light source |
| Switch ×1 | Switch |
| Nickel strip / tape | Cell leads and securing |
| Spot welder (UK1) ×1 | Welding the strip |
| 3D-printed shell ×3 | Self-modeled · Enclosure |
| ALIENTEK multimeter ×1 | Measuring |
Creator’s tips
- Fold the nickel strip flat and secure with tape so it doesn’t stick out 00:54
- A low-power color-changing LED (0.01A) on a 2000mAh cell runs a month 00:28
- LED negative straight to the output, switch on the positive 01:35
Pitfalls
- Comments: no separate BMS, safety for student use questioned
- Comments: the charging port sits too low to plug in easily; a black shell diffuses light worse than white
Li-ion safety
- A Li-ion night light with no BMS (only a charge-management module); comments suggest adding a BMS and thicker leads
Quotes
Cost & time
| Time | Over 4 hours to print three sets |
