diff --git a/content/posts/2022/led-lighting.md b/content/posts/2022/led-lighting.md new file mode 100644 index 0000000..ea0f6c0 --- /dev/null +++ b/content/posts/2022/led-lighting.md @@ -0,0 +1,187 @@ +--- +title: "Home Automation with LED Lighting" +date: 2022-09-23T10:58:11+02:00 +draft: false +toc: false +images: +tags: + - electronics + - lighting + - DIY +--- + +As a small side project I am installing LED lighting in on of the rooms at my +place. There are quite a few interesting details that is worth taking note on. + +## Hardware Preparation + +Before buying the bulk of my hardware I ordered a smaller quantity to +assess build quality and see how it all fits together. All components discussed +below are ordered from aliexpress while the AC-DC power-supply will be purchased +locally for safety and certification reasons. + +### 12 V and 24 V LED Strips + +LED strips are advertised at different voltages but generally all operate the +same way by stringing sets of LEDs in series and then having multiple sections +in parallel. The voltage specification will limit the number of LED you can +put in series due to the voltage requirement on each device which means that +12 V strips will use smaller groupings and yield 10 to 20 cm cuts. Strictly +speaking device or power density will be independent of the operating voltage. + +The efficiency for either voltage is comparable but the 24V configuration will +do slightly better by sharing the current limiting resistor over more LEDs. + +``` goat + 12V / 24V SUPPLY + -------*------*------*------*------*----> + | | | | | + +-+-+ +-+-+ +-+-+ +-+-+ +-+-+ + LED \ / \ / \ / \ / \ / 3V Drop + --+-- --+-- --+-- --+-- --+-- + | | | | | + | | | | | + +-+-+ +-+-+ +-+-+ +-+-+ +-+-+ + LED \ / \ / \ / \ / \ / 3V Drop + --+-- --+-- --+-- --+-- --+-- + | | | | | + | | | | | + +-+-+ +-+-+ +-+-+ +-+-+ +-+-+ + LED \ / \ / \ / \ / \ / 3V Drop + --+-- --+-- --+-- --+-- --+-- + | | | | | + +-+ +-+ +-+ +-+ +-+ + \ \ \ \ \ + LIMITING +-+ +-+ +-+ +-+ +-+ 0V to 3V + RESISTOR \ \ \ \ \ Drop + +-+ +-+ +-+ +-+ +-+ + \ \ \ \ \ + + + + + + + | | | | | + <-------*------*------*------*------*----- + Lighting Control Signal +``` + +### Individually Addressable LED Strips + +Some of the advertised LED strips come with integrated controllers where +brightness levels can be adjusted for each section. The advantage is that +this allows you to animate the lighting or create intricate patterns along +the LED strip. Note that the failure of a single controller +will cause the entire strip to fail rather than just one section of LED lights. +Another detail is different integrated don't all provide equivalent lighting. +A RGB LED for example emits with a luminosity of 600, 1250, and 300 mcd +while a dedicated white-channel LED emits around 4000 mcd or around 12 lumens. +Specification wise SK6812 RGBW does seem like a good choice here especially +since the estimated power requirement is 9 Watt per meter. + +The main caveat however is that controllers can require a quite a bit more +effort to operate with the added functionality. Given the Chinese quality +standards a home-brew ESP32-H2 solution would be preferred. Besides that +the efficiency/performance seems very similar to that of non-individually +addressable solutions looking mostly at Watt per meter figures. + +### Prototyping hardware + +The LED controller from GLEDOPTO cost me $19.99 USD and provides +6 channel (RGB+CW) lighting with maximum capacity of 270 W. The 6 channel +LED strip similarly cost me $22.00 USD for 5 meter of lighting. +This strip uses 21 Watt per meter which means the controller could drive 11 +meter of lighting. Here are some more details for the LED strip: + +|LED Strip |Specification | +|--------------|------------------------| +|Model Number | MF350Z090A80 | +|LED Type | 5050 RGB | +|CCT Colour | 622 nm, 522 nm, 465 nm | +|Beam Angle | 120 ° | +|Voltage | DC 24 V | +|Current | 0.83 A/m | +|Power | 20.2 W/m | +|LED Density | 30 Units/m or 12/cut | +|Brightness | 1457 Lumen/m | +|PCB Width | 12 mm | +|Cost | $4.4 USD/m | + +Note that the density here is with respect the density for a single LED channel. +Originally it is quoted at 90 Units/m since there are 3 devices for the 6 channels. +Similarly the brightness is optimistically the sum of each channel together. +The controller is specified below: + +|Zigbee controller |Specification | +|------------------|----------------------| +|Model Number | GL-C-008 | +|Input Power | 270 W Max | +|Input Voltage | DC 12-24 V | +|Output Current | 15 A or 6 A/channel | +|Dimensions LWH | 8.0 x 4.8 x 2.4 cm | +|Recommended Load | 10 m | +|Cost | $1.99 USD / m | + +The key detail here is that we should match certain lengths with designated +controllers. For example the room I intend to illuminate has a 11 meter +perimeter and I would prefer to use just one controller which implies +I should keep in mind that I can probably only illuminate part of the ceiling. + +For preliminary testing I also ordered 10 meter of diffuser that is compatible +with the 6 channel LEDs. + +|LED Diffuser |Specification | +|-----------------|----------------------| +|Model Number | T0515 | +|Type | Minimal enclosure | +|Dimensions WH | 1.5 x 0.5 cm | +|PCB Width | 12 mm | +|Cost | $2.66 USD / m | + +While we have not included the price here for a 24V 10A AC-DC converter required +to power this setup, it is interesting to note the majority of the cost comes +from the LED strip is self. As explained below I probably wouldn't purchase +this particular diffuser again since at least for my application other +lighting configurations seem more useful. I also ordered a bunch of LED utility +items that is compatible with the 6 channel strip including some T-junctions +and L-junctions. These are mainly just for wiring and don't contribute to +lighting but could make the general configuration look a bit more integrated. + +### LED Placement + +One issue with LED lighting is that generally we would prefer a contiguous +strip of lighting even around corners but depending on the orientation and +diffusion this may not be possible. It is generally better +to orient the strip facing the corner which means that side-illuminating +diffusions are generally more aesthetically useful. For example when we +want to illuminate the perimeter of the ceiling it is not possible the to +make right-angle turns with contiguous lighting when the LEDs are facing the +floor. + +Instead having the strip face this inside of the room with a +downward/sideways diffusing shroud avoids this issue where we need to break up +or fold the lighting which cannot be done readily. + +``` goat + 3.6 meters + .-----------------. + | 11m OFFICE | 1.9 + | 220W / 110W | meters + | 330 units | + +-----------------+---------------+-----------------------. + | 15m HALL WAY | | + | 1.5 300W / 150W | 19m LIVING ROOM | + | meters 450 units | 380W / 190W | + | 5.8 meters | 570 units | 3.8 + +-----------------+---------------+ | meters + | 10m BED ROOM | | | + | 200W / 100W | 2.0 | | + | 300 units | meters | | + '-----------------+ '-----------------------' + 3.1 meters 5.4 meters + + Total Perimeter 55 meters. Power Estimates for 20/10 Watt per meter. +``` + +The diagram above roughly illustrates some of the rooms I was considering to +light using this LED setup. It is worthwhile to estimate the maximum power +requirement for the mains transformer that is supplying the 24 V DC supply. +I found that I can readily get a good quality 150 Watt AC-DC transformer +for about $50 USD which means for most rooms a lower power configuration would +be preferred.