The floor lighting dates back to 18 years ago. It was originally incandescent, then CFL to get more light than it was rated for. It never was ideal. The bench was never well lit. The lighting took a lot of floor space. The last CFL burned out in 2019, ending their 18 year reign & there was no desire to replace them with LED bulbs in the same floor lamp. Recessed lighting was the most attractive option, but difficult to implement. LEDs were attractive because they were flat & could stick to the ceiling.
LED strip lights to this day are still relegated to cabinet lighting & accent lighting. They're just not bright enough to replace conventional lights. The lion kingdom wanted to change that. A strip light combined with 8W bulbs that were converted to flat mounts & low DC voltage produced enough light to replace a floor lamp. The strip light was actually not entirely worthless. It produces enough light to be unacceptable with it off. As they get cheaper, more strip lights will be added to eventually replace all the 8W hacks.
All the LEDs still worked, after the early failures of some reconstituted 8W bulbs. The mane casualty was the 15V Mean Well power supply. It suddenly went to 0V after the 1st heat wave of the year. Its fan had been removed during the winter because of the noise. Without the fan, during the Summer, its heat sinks were getting to 50C. The hottest parts were the heat sinks & the RF choke rather than the transformer.
Thus, it was proven that the Mean Well needs a fan. It actually came back to life once cooled. It seemed to have a thermal fuse which needed to cool to room temperature to reset.
It was disappointing to find LED strips had not improved in the last year. The 8W bulbs are being made with fewer LEDs of higher voltage. Lions still wire them in series to reduce the rework. The latest ones use 11V per LED, putting series LEDs above laptop power supplies. Lions still avoid running manes voltage in exposed wires on the ceiling, though running 44V to have 4 LEDs in series is tempting.
By spreading purchases over a longer time, it might be possible to build up more LED strips to replace the reconstituted 8W bulbs.
Not described on the internet was that it had no IEC manes connector, no fan, no soft switch. It really was just a bare board with screw mounts.
Most of the board was empty, thus giving a very empty space in need of an enclosure. There was a trimpot for adjusting the voltage. The range was 13.5-18V. Fortunately, there was a spare manes connector from the dead 250 watter with ancient style screw holes.
After a day of fabricating, it had been enclosed in tupperware.
The screw mount was modified for easier cable routing. Be sure neutral & GND aren't shorted, live & neutral aren't reversed, the chassis is GND, & your manes are heat shrinked. Test without a load to adjust the pot.
After 6 months, the LEDs were back. They couldn't get as bright as before, because experimenting with PWM over drove them. You can't drive LEDs with PWM & get the same brightness as a DC voltage.
They were nowhere nearly as bright as a pair of 60W fluorescents, but the fluorescents drove PG&E from $100 to $130/month. Brighter results with LED strips would cost a lot more than edison mounted bulbs of any kind. The power supply is going to be expensive & maxed out.
Decided it would be easier to take another swing at repairing the vintage AT power supply than trying to hack a modern ATX supply. Quickly spotted a bodge wire melted onto a diode. The diode was shorted. 2 of these diodes rectify the output of the mane transformer, using a center tap. The component that blew was an FR302 diode. Replaced it with a 1N5400 & then a SN30SC4. Both worked without a load, but immediately blew after briefly lighting the LEDs. It pointed to a transformer winding that shorted under load & the short was on one side of the center tap, putting 120V across only 1 diode. That was all for the 20 year old supply. It was back to dropping laptop voltage with PWM.
Robot board from 2002
Converted into a PWM board, today
Recycling the very 3rd microprocessor board a lion ever built was a reminder of those days. The board seems to have changed color after 17 years. There was no oscilloscope, no USB, no current limited power, & no temperature controlled soldering iron. Instead of an FTDI chip, there was a MAX232 which plugged into a computer's 9 pin serial port. The attitude was don't build anything that would be cheaper to buy, which led to copying a schematic & hoping it would work. Without an oscilloscope, the 1st microcontroller board was abandoned.
Lions assumed microcontrollers only used the standard baud rates of personal computers when in fact it was an arbitrary number based on the clockspeed. Determining the baud rate was the 1st task in bringing up every later board.
The 68HC11 was the best microcontroller available. It was pathetic, but a friggin computer on a chip. Lions still recycle old microcontrollers, but not as primitive as the 68HC11. The 68HC11 actually had 4 more PWM outputs than the early PICs. It was programmed entirely through the serial port, which made the baud rate critical for getting anywhere with it.
The new dropper used an overkill microcontroller for 1khz PWM, but it's all about retiring these vintage microcontrollers. The LEDs got a lot hotter when pulsed at 1khz than when at DC. What used to run on 9V RMS now got hot at 2.5V RMS & appeared a lot dimmer. The dropper made a clear 1khz sound & the laptop brick got hot.
LED strips may still be too expensive to replace manes voltage floor lamps. Key changes with the giant square would be using interconnects instead of soldering the entire thin PWM is the accepted way of dimming LEDs, but it's obviously very inefficient.g in 1 piece & making the sides equal length. It would be much easier to erect if it used interconnects.
Developing a power supply is harder than it looks. The commercial ones output 12V which drops significantly by the time it reaches the strip. There are multiple, random LED strips with different voltages. Multiple voltage droppers for a single laptop power supply would be the easiest way. After considering how to drop multiple voltages with the cheapest microcontrollers, Mike Harrison introduced a PWM generator based on 2 op amps. 1 op amp generates a triangle wave. The other op amp is a comparator that chops the triangle wave into PWM. It could be far simpler than a microcontroller.
LTSpice showed it can work, but it requires higher speed op-amps which are only in surface mount. The trick with LTSpice was arranging the power supplies exactly as shown. A single supply or a -5V supply didn't work. It would actually take more parts than a single microcontroller.
It worked for several weeks, then suddenly went dark & the power supply let out the magic smoke. The power supply was dropped. It somehow cracked a fan blade, causing it to stop. It must have over heated & fried a component. 12V was shorted to ground. All the caps were intact. It was probably a delaminated transformer winding. There was only 1 more supply, a 2005 era 500W deal. All the others from before 2001 were recycled to conserve space. It used a PS223 protector but had no obvious voltage regulator on the low voltage side. That was the end of computer power supplies.
The next step would be making another PWM circuit for another 90W laptop power supply. The total number of new PWM circuits would be 2, since using a transistor as a resistor is super inefficient.
Seeing it from the outside, it clearly should be random alien characters rather than a square. It already looks kind of futuristic. Alien characters would make the illiterate humans freak out. All future buildings are going to be lit by alien characters stuck to the ceiling where floor lamps used to be.
Pulling it off requires wires too long to support the high current of the Lighting Evers.
Of course, there aren't many hieroglyphs of any kind which don't make humans have a shit fit. They'd burn the library of Alexandria, if they could read.
The dollar store is normally a ripoff. It's quite easy to spend more on $1 lights than another rectangle. Only got 6 of the $1 bulbs. They have Sunbeam & Brichips. The Sunbeams have 16 LEDs in series, running directly on manes voltage with a rectifier, a BP5131h linear regulator, & no caps, so it's just clipping the peaks. The Brichips have 11 LEDs in series, running on 60V. Neither lasts very long on manes voltage.
The Sunbeams are a lot more work to convert, but put out more light. Through Chinese patience, the traces can be cut, ground, & resoldered to take 17V. On the Brichips, 2 LEDs can be smashed to reduce it to 17V.
This way, multiple bulbs can be stuck on a strip & powered by a single 17V supply. The design had evolved to random strips of LEDs on the ceiling, where floor lamps used to be, in addition to the giant rectangle.
Scotch mounting squares are smaller versions of the same thing that existed 20 years ago, for 1000% the price. They're so far effective at sticking LEDs to the ceiling. The light from the LEDs actually hides most of the wiring.
To this day, China still doesn't provide strips suitable for sticking on a ceiling, but it's obviously the future.
Not all the LEDs survived the rework, but the random arrays left over had a certain alien look. Smashing random LEDs would make it more artistic, but expensive. A simple transistor dropper reduced 19V to 16.5V.
It was finally bright enough to replace the floor lamps.
For the next revision, the rectangle should be a square & farther from the wall. The square should be doubled up instead of relying on extra strips.
11 LEDs in series burn around 60V at 20mA. They have acceptable color. They get hotter than the blazes of hell & damnation itself, relying on the base & the screw mount for cooling. Like all LED bulbs, the LEDs can't be extracted. The mane advantage is they have room to bolt on a heatsink & rework. The LEDs aren't wired in numerical order. If LEDs 11 & 6 are smashed, they can be points for wiring in 3 parallel. That makes 16V at 60mA. There's no way to reconfigure all 11 for a lower voltage.
It's leading towards random arrays of inexpensive LEDs. Suspect all apartments of the future will be lit by taping random LED strips to ceilings. It would be nice if LCD backlights could be used, but they're too blue.