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The Luxeon LED Spotlight being used as a headlight on a Greenspeed pedal-powered recumbent trike. The car in the main beam is 35 metres away. Note also the broad, lower intensity illumination immediately in front of the trike. Even on roads that have no street lights, sufficient illumination is provided to allow pedalling at up to 75km/h. PART 2: By JOHN CLARKE & JULIAN EDGAR Universal High-Energy LED Lighting System Last month, we introduced our brilliant new Luxeon LED lighting system and described how it works. This month, we look at its construction and describe how to make a very effective Luxeonpowered spotlight. T HE UNIVERSAL High-Energy LED Lighting System is built on a PC board coded 11004061 (104 x 79mm) and is housed in a diecast aluminium box (115 x 90 x 55mm). An aluminium box was used because it provides sufficient heatsinking for Mosfets Q1 & Q2 and for the battery pack (this 44  Silicon Chip heatsinking is needed at high charge and discharge rates). In addition, the aluminium housing is rugged and weatherproof. Board assembly Fig.2 shows the parts layout on the PC board. Begin construction by care- fully checking the PC board for breaks or shorts between the copper tracks. Repair any defects (rare these days), then install PC stakes at all the external wiring points. Follow these with all the low-profile parts including the wire links, resistors, small capacitors and the diodes. siliconchip.com.au It might look like a bland box but there’s a lot inside! Visible is the cover for the LDR (left) and at right, the on/off pushbutton and the battery status LED. The weatherproof Luxeon output cable can also be seen. Fig.2: install the parts on the PC board as shown here. Note that R1 is a surface mount resistor and is installed on the copper side of the board. Note also that the 4700mF capacitor is mounted on its side – see photos. Once these parts are in, you can install the surface-mount resistor (R1) on the copper side of the PC board. You will have to refer to Table 5 to determine which of the two provided surface-mount resistors is installed. Next, install the electrolytic capacitors, voltage regulator REG1 and the transistors but leave the two Mosfets out for the time being. Make sure that these parts are all correctly orientated (the same goes for the diodes). Note that the 4700mF capacitor is not mounted vertically – instead, it is positioned on its side (see photo). Be sure to leave sufficient lead length to allow for this positioning. When winding T1 and L1, use a generous smear of silicone sealant under and over each winding layer. Also smear silicone on the top and bottom of the mating surfaces of each core half. Note that both L1 and T1 require 0.5mm spacers to separate their pot cores (these can be made Winding the inductors Inductor L1 and transformer T1 can now be wound. L1 simply consists of 38 turns of 0.63mm enamelled copper wire on an FX2240 pot core and bobbin assembly. By contrast, T1’s windings depend on the LEDs being driven (see Table 5). It’s also easy to make – just wind on the primary turns, then neatly wind on the secondary turns over the top – see Fig.3. The windings can go in either direction. Table 4: Capacitor Codes Value μF Code EIA Code IEC Code 100nF 0.1µF   104 100n 1nF .001µF   102 1n0 Table 3: Resistor Colour Codes o o o o o o o o o o o siliconchip.com.au No.   3   1   2   2   2   2   2   1   1   1 Value 470kW 220kW 56kW 10kW 2.2kW 1kW 470W 330W 1W 47W 10W 4-Band Code (1%) yellow violet yellow brown red red yellow brown green blue orange brown brown black orange brown red red red brown brown black red brown yellow violet brown brown orange orange brown gold yellow violet black brown brown black black brown 5-Band Code (1%) yellow violet black orange brown red red black orange brown green blue black red brown brown black black red brown red red black brown brown brown black black brown brown yellow violet black black brown not applicable yellow violet black gold brown brown black black gold brown May 2006  45 Table 5: Transformer Winding Data & LED Current Luxeon Option Transformer (T1) LED Wiring 1 x 1W R1 2W TP2 Individual LED (VR4 adjust) Current Primary (0.63mm ENCU) Secondary (0.63mm ENCU) 22 Turns 13 Turns 0.5W 175mV Total LED Current Test Resistor 350mA 350mA 10W 5W 2 x 1W Series 16 Turns 22 Turns 0.5W 175mV 350mA 350mA 22W 5W 3x1W Series 17 Turns 33 Turns 0.5W 175mV 350mA 350mA 22W 5W & 10W 5W in series 4 x 1W Two lots of series 2 x 1W in parallel 26 Turns 32 Turns 0.2W 140mV 350mA 700mA 10W 10W 6 x 1W Three lots of series 2 x 1W in parallel 26 Turns 36 Turns 0.2W 210mV 350mA 1.05A 6.8W 10W 22 Turns 17 Turns 0.2W 200mV 1A 1A 3.3W 5W 26 Turns 36 Turns 0.2W 200mV 1A 1A 6.8W 10W 26 Turns 36 Turns 0.2W 140mV 700mA 700mA 10W 10W 1 x 3W 2 x 3W Series 1 x 5W As shown in this table, the number of turns wound on the transformer, the value of resistor R1 and the adjustment of trimpot VR4 all depend on the LEDs that are to be driven. In addition, this table shows whether the LEDs are wired in series, parallel or a series/parallel combination. Note: there is no option to use five 1W LEDs. from 0.5mm plastic sheet). These spacers sit between the central bosses of the pot cores. The final step in the construction of these components is to force silicone into the gaps on the outside of the cores. Clean up the edges with a sharp knife when the silicone has set. Important: if you do not use sufficient silicone, the inductor and transformer will emit buzzes and squeals – so use plenty of it! Having completed winding the inductors, they can be installed on the PC board. Be sure to orientate T1 so that its secondary winding goes to the right, so that the leads connect to the bridge rectifier (D3-D6). Other parts Switch S1, the battery charge/ discharge LED (LED1) and the LDR Fig.4: Mosfets Q1 & Q2 must be insulated from the metal case using insulating washers and Nylon screws, as shown here. Note that the Nylon screws should be cut to length. Changing the PWM Frequency Fig.3: transformer T1 is wound using 0.63mm enamelled copper wire – see Table 5. The windings can be made in either direction. To reduce noise, the windings should be sealed with silicone, as described in the main text. Note that a 0.5mm spacer is inserted in the middle of the cores for both T1 and inductor L1. 46  Silicon Chip During normal operation, a faint “squeal” is emitted from the electronic circuitry or more specifically, from the transformer. This can be quietened if a higher (13kHz) PWM frequency is selected, rather than the default 7.8kHz. The downside is that the dimming functions will not work as precisely. To change the frequency, first select position 14 (E) on the BCD switch. That done, wait for the red LED to come on and then turn off, then select another switch position. The frequency will change from 7.8kHz to 13kHz, which is virtually inaudible in this application. If you select position E again, the PWM frequency will revert to 7.8kHz. siliconchip.com.au To provide clearance, the stand-offs within the box must be removed. This can be done by using a large-diameter drill bit followed by a high-speed deburring tool or a grinding stone held in the chuck of an electric drill. can now all go in. In each case, leave sufficient lead length to allow these components to be bent back out of the way when fitting the PC board into the box. The LED must be mounted with its leads bent at right angles, so that it can later be pushed through a matching hole in the side of the case. Before the PC board can be fitted into the box, the integral stand-offs need to be removed. This can be achieved using a large diameter drill, followed by a high-speed deburring tool or a grinding stone held in the chuck of an electric drill. Wear safety goggles when performing this job. Once the standoffs have been removed, position the board inside the case and mark out and drill the four corner mounting holes. These holes should be countersunk, so that the heads of the Nylon mounting screws The electronics are a tight fit in the box, with one capacitor being placed on its side. Be sure to wind the inductors tightly, to minimise audible high-frequency noise from them. sit flush with the lower surface of the box. That done, temporarily secure the board in position using 4mm-long Nylon spacers and 3M x 12mm Nylon screws and nuts – see Fig.5. Note: the four 4mm-long Nylon spacers are made by cutting two 9mm spacers in half. Mounting the Mosfets The next step is to determine where the mounting holes go in the case for the two Mosfets. To do this, first crank their leads slightly as shown in Fig.4, then slip them into their board mounting holes. Next, push the two Mosfets down into their holes until they are about 12mm proud of the board and position them so that their metal tabs sit flat against the case. You can now mark out their tab mounting holes from inside the case. Once that’s done, remove the PC board (and the Mosfets), transfer the hole locations to the outside of the case and drill them to 3mm. These two holes Mounting The PC Board Inside The Case Fig.5: the PC board is mounted inside the case on M3 x 4mm Nylon spacers and secured using M3 x 15mm Nylon screws and nuts. siliconchip.com.au May 2006  47 Adjusting The Charging Current In its default condition, the Universal High Energy LED Lighting System is designed to be used with a power source that can recharge the batteries at up to 700mA. Note that because of the temperature rise that occurs primarily in the batteries, this is the maximum recommended continuous charge rate. However, there are some applications where better results can be gained by altering this charge rate. For example, if you’re using a solar cell, you may have a maximum charging current capability of only 300mA available. On the other hand, if you’re using a human-powered generator that can develop discontinuous bursts of 1A, you may want to charge at this higher rate. As a result, the charging current can be set anywhere from 100mA to 1A in 50mA increments. Note that the charging current referred to here is the current delivered to the Universal High Energy LED Lighting System, not the current supplied to the battery. The current supplied to the batteries is dependent on both the input voltage and the charging voltage. At input voltages between about 8.6-12.6V, the battery charging current is similar to the input current. Above 12.6V, however, the battery charging current increases with input voltage. For example, at 18V input, the battery is charged at about twice the current that is supplied to the input. This is possible because the charging circuit is a power converter – it converts the high input voltage into a lower voltage to correctly charge the battery and at the same time, increases the battery charging current. To change the charging current from its default value of 700mA, just follow these two steps: (1) Set the BCD switch to Mode 15 – marked as ‘F’ on the switch. The green indicator LED will then flash at a 1-second rate, to show the charging current that has been set. Each flash equals 50mA and there is a 2-second break between each flash group. For example, at the default 700mA charge rate, the LED with flash 14 times, then there will be a 2-second delay, then it will flash 14 times again, and so on. (2) To alter the charge current, press the pushbutton switch and hold it down, counting the number of flashes. Let the pushbutton go when the required current value has been reached. The LED will acknowledge the new setting with a revised flash number. Note that if the BCD switch is changed while the current reading is being flashed, the LED will continue to flash the code until it finishes its sequence. Note also that plugpacks are not generally used at their full rating. This means that if you have (say) a 700mA-rated plugpack and you set the charging current to 700mA, you can expect the plugpack to become quite warm. R1 (arrowed) is a surface-mount resistor that is placed on the copper side of the PC board. Also visible here are the cable ties used to hold transformer T1 and inductor L1 in place. 48  Silicon Chip Adjustments & Test Points VR1 – sensitivity of the Light Dependent Resistor VR2 – sensitivity of the thermistor VR3 – reference voltage VR4 – Luxeon LED current S1 – operator’s pushbutton S2 – Mode BCD rotary switch TP1 – test point for setting reference voltage TP2, TP GND – test points for measuring voltage across R1 to set LED current must then be carefully deburred using an oversize drill so that the inside surfaces are smooth and free of any metal swarf which could later puncture one of the insulating washers. The next step is to remount the PC board inside the case, after which the two Mosfets are mounted in position. Bolt them to the side of the case using M3 screws, then use a sharp pencil (or a fine-tipped pen) to mark where their leads meet the PC board. Before removing the board again, you also need to mark out the hole locations for the cable gland, the pushbutton switch, the indicator LED and the charging socket. Similarly, if the LDR is not going to be mounted remotely, a hole also needs to be made for this component (this can go in the lid or in the side of the case). The accompanying photos show the locations of the various holes. Be sure to position these holes accurately – installing the PC board and its associated hardware in the case requires care, as clearances are very tight. If you don’t need such a compact assembly (or the Universal High Energy LED Lighting System is being incorporated into other equipment), then feel free to use a larger box – but don’t forget to adequately heatsink Q1 and Q2. Suitable alternative heatsinks are 19 x 19 x 10mm U-shaped designs. Having marked the hole locations, remove the PC board and the Mosfets from the case once again. The Mosfets can now be finally soldered to the PC board – just push them down until the pencil marks on their leads meet the siliconchip.com.au board surface, then carefully solder these leads to their respective pads. Now drill the holes in the case for the other parts. The square cutout for switch S1 is best made by drilling a hole that’s smaller than the finished size and then filing to the required rounded rectangular shape. Once that’s been done, the PC board can be finally mounted in place (see Fig.5) and the two Mosfets (Q1 & Q2) secured to the side of the case. Fig.4 shows the mounting details for the Mosfets. Note that they must be electrically isolated from the metal case. This is achieved by using a silicone washer and by using M3 x 15mm Nylon screws and nuts to fasten them in position. Having secured them, switch your multimeter to a low “ohms” range and check that the device tabs are indeed correctly isolated from the metal case. The switch, indicator LED and the LDR can now be pushed through their respective holes and secured in place with silicone sealant. The cells, main fuseholder and thermistor are glued to the inside of the lid using silicone sealant – see Fig.6. Note the location of the thermistor – it should be placed in the centre of the battery pack. Make sure that the cells sit hard against the lid and leave plenty of time for the sealant to fully cure before moving the assembly. We used C cells that did not come with solder tags but since soldering directly to NiMH cells is not recommended, we suggest you use cells with tags. Use 7.5A wire for the batteries, 5A wire for charger leads and twisted pair light-duty hookup wire for the NTC thermistor. A few precautions Before moving on to the setting-up procedure, there are a couple of precautions you need to observe. First, always make sure that the power is off when working on the circuit. This Fig.6: the four 4500mAh cells, the fuseholder and the thermistor are glued to the lid using silicone sealant. They must be wired as shown here. can be done by removing the main battery fuse. Second, after the circuit has been running, the 4700mF capacitor must be discharged. To do this, press the switch twice in modes 1, 2 or 3 to momentarily light the Luxeon LEDs. Incidentally, transformer T1 becomes hot when powering a full Luxeon load and at high charge rates, the batteries also become quite warm. meter to check that there is battery voltage between pins 5 & 14 of IC1. If there is sufficient charge in the battery pack, this voltage will be 5V. (2). Adjust the reference voltage: con- Setting up Make sure that the battery pack is connected with the correct polarity, then install the fuse. You now need to go through the following setting-up procedure: (1). IC1 power check: Set S1 (the BCD Mode switch) to F, then use a multi­ FOUR 1W LUXEON LEDS Matching The Light From Multiple Luxeons If the Luxeons are wired with parallel connections, it is best to match the devices so they each have a similar brightness. Devices with exactly the same type number printed on the back are generally the same in terms of voltage drop at the rated current. If you find that one or more Luxeons in a series/parallel connection is dimmer than the rest, it is not well matched with the others. In that case, reduce the drive current using VR4, so that the brighter LEDs are not over-driven. siliconchip.com.au SIX 1W LUXEON LEDS Fig.7: in most cases, wiring the Luxeon LEDs is straightforward. However, when running four 1W or six 1W Luxeons, series/parallel arrangements must be used, as shown here. May 2006  49 This version of the spotlight differs a little from the one described in the text in that aluminium – rather than U-PVC plastic – has been used to form the front rim. The aluminium rim was machined from the base of an old BCF aluminium fire extinguisher. When there’s usually plenty of airflow, the heatsink shown on this light is effective with a 5W Luxeon LED. In non-ventilated applications, a larger heatsink should be used. Making a LED-Powered Spotlight – use it as a bicycle headlight Here’s how to build a durable and effective LED-powered spotlight – great for use as a bike headlight or for use as hand-held long-range lighting system. The light output is just outstanding – in fact, when you consider its miserly 5W power consumption, it’s nothing short of fantastic. Apart from the electronic control you only need a handful of parts. The accompanying parts list shows what you need. Building it OK, let’s build it. First, cut a hole about 65mm in diameter in the centre of the plastic plumbing cap. Sand the edges smooth and then use silicone to glue the lens within the cap. This assembly forms the focusing lens. Next, drill holes in the heatsink to allow small nuts and screws to be used to attach the LED to the heatsink. Drill an additional pair of holes in the heatsink to allow the power supply 50  Silicon Chip wiring to the LED to pass through the heatsink. Alternatively, these wires can pass through a hole drilled in the stainless steel drinking cup. Now use a file to shorten the plastic legs of the collimating lens so that it sits squarely over the LED, legs resting against the heatsink and the centre of the collimator in contact with the LED. Place some heatsink compound under the LED and then attach it to the heatsink using the small screws and nuts. Check that the heads of the screws do not short the power supply connections to the LED (you may want to use Nylon nuts and bolts). Once the LED is in place, glue the collimating lens securely in place. That done, pass the wiring through the heatsink and solder it to the LED, then seal the holes through the heatsink with silicone. The next step is to cut a 35mm hole in the centre of the bottom of the stainless steel cup. If the spotlight is to be permanently mounted, drill the cup for any brackets that will be needed. Deburr all holes, then position the heatsink on the bottom of the cup so that the LED and collimator lens project through the 35mm hole. Finally, mark and drill the holes to bolt the heatsink to the cup, sealing this join with silicone. Testing Test the operation of the LED with the focusing lens in place. The assembly should throw a very bright spot of light about 600mm wide on a wall three metres away. This beam angle is ideal for a long-range bike headlight, or for a general-purpose spotlight or high-powered torch. If all is working satisfactorily, use silicone to glue the lens assembly in place. Performance The performance of the prototype siliconchip.com.au Par t s Lis t Making A Low-Cost 1W Luxeon LED Housing 1 5W Luxeon LED 1 narrow-beam collimating lens (eg, Jaycar ZD-0420) 1 large finned heatsink to suit the LED – eg, Altronics Cat. H0520 or an ex-PC processor heatsink 1 stainless-steel drinking cup 1 U-PVC plastic plumbing cap that fits over the open end of the cup 1 magnifying glass (glass – not plastic!) the same diameter as the open end of the cup Assorted small nuts and bolts Note: in most cases, the cup mouth will have a diameter of 75mm, making it easy to source the plastic cap and magnifying glass. Here’s how to make a durable and good-looking weatherproof housing for a 1W Luxeon LED when it’s used with either Jaycar ZD-0420 or ZD-0422 collimators. You’ll need a PVC 25mm Class 18 pipe cap (about $3 from a hardware store), some black silicone and a few hand tools. Start by using a file and sandpaper to smooth away the raised writing to be found on the back of the cap (this doesn’t do anything for the engineering but a lot for the aesthetics!). That done, drill a hole for the cable entry and also any other holes needed for mounting brackets. If used, the brackets should be attached at this point. And if you intend painting the housing and bracket, do it now. Next, solder the wires to the LED, feed them through the hole in the housing and position the LED at the bottom. Secure it in place with some silicone, then shorten the legs on the collimator so that it sits over the top of the LED. Carefully apply silicone around the upper part of the collimator, ensuring that you seal the gaps. You can now slide the collimator into place in the housing, making sure that it engages with the LED. Use a rag to carefully wipe away the surplus silicone but be sure to fill any gaps around the edge of the LED. Finally, place a little silicone around the cable exit to seal this opening. Note that because there is no provision for heatsinking, this housing is not suitable for 3W and 5W LEDs. unit – which is used as a bike headlight – was outstanding. On a country road lacking any street lights, and tested on a very dark night with no moonlight or starlight, sufficient illumination was provided by the headlight to allow for safe pedalling downhill at over 75km/h. Used as a handheld spotlight, it could easily illuminate trees 50 metres away. If less power is required, a 3W LED can be used in place of the 5W LED. If the assembly is always going to have airflow over it (eg, if it is being used as a bike headlight), the 3W LED can be bolted to the inside of a single-wall cup and the cup itself used as the heatsink. This saves having to make the large hole in the bottom of the cup and removes the need for a separate, finned heatsink. A stationary 3W light should retain the finned external heatsink. If you want the best, though, the 5W design described above is it! But if you simply want a compact but still very effective spotlight beam, the 3W Luxeon with the Jaycar narrow beam collimator (Cat. ZD-0420) gives excellent results. Finally, single-wall stainless steel drinking cups can now be very hard to find but Coastal Kitchen and Cutlery on the Gold Coast (07 5526 9399) have them in stock at $5.50 each. A double-wall (ie, insulated) cup can also be used but it is heavier and more difficult to drill. siliconchip.com.au nect a multimeter between the negative battery lead and TP1. Adjust VR3 for 2.490V. (3).Thermistor calibration: adjust trim­ pot VR2 so that there’s 1.25V across the thermistor terminals at 25°C. (4). Connect the test resistor: wire a test resistor across the Luxeon LED output (ie, in place of the Luxeon LEDs). Table 5 shows the value to use. Also, use Table 5 to check that both R1 and T1 are correct. (5). Setting the LED current: set VR4 fully anticlockwise and set S2 to Mode 1. Switch on the system by quickly pressing S1 twice. Measure the voltage between TP GND and TP2. Set the correct voltage using VR4, according to Table 5. Note: during this process, the test resistor will get very hot. (6). Connecting the LEDs: wire in the Luxeon(s), making sure their polarity is correct and ensuring the Luxeons are adequately heatsinked! Again The multi-position BCD switch (centre) sets the operating mode of the system. Also visible is the Light Dependent Resistor (arrowed) that’s used in some modes to automatically switch on the Luxeon LED as ambient light changes. Depending on requirements, this LDR (arrowed) can either be mounted within the box (and sensing the light through a cut-down neon bezel) or mounted remotely. May 2006  51 Be Sure To Provide Adequate Heatsinking Heatsinks must be used with both 3W and 5W Luxeon LEDs. Even the 1W LEDs, which normally don’t require additional heatsinking, can do with some additional heatsinking when run continuously at full power in hot conditions. In all cases, keeping the LED junction temperature low will give greater light output and longer LED life. The size of the required heatsink depends on: • the nominal power of the LED; ABOVE: a processor heatsink • whether it is run at maximum salvaged from an old PC is ideal current; for cooling 3W & 5W Luxeon • whether it is on continuously or is LEDs. Remove the old heat flashed (and if flashed, the duty cycle); transfer pad in the centre using solvent, before attaching the LED. • the ambient temperature; ventilation; and • • the thermal resistance of the heatsink. If there is plenty of space available, it pays to simply run the best heatsinking possible. In all cases, care must be taken to ensure that the aluminium face of the PC board used for the LED is thermally connected to the heatsink. The heatsink must be absolutely flat (no burrs from drilled holes) and a smear of heatsink compound should be placed between the LED’s PC board and the heatsink. In addition, the LED should be held in place securely with nuts and bolts. Ex-PC processor heatsinks are excellent for Luxeon LEDs, with older 486-sized heatsinks suiting 3W LEDs and larger heatsinks from later model PCs suiting the 5W LEDs. If ventilation is poor, the fan that’s often found attached to these heatsinks should be retained. If the LED drive voltage is nominally 6.8V (as it is when running a single 5W LED or two series 3W LEDs), the fan can be wired directly across the Luxeon output. It will rotate more slowly than if fed from 12V but it will still spin fast enough to greatly improve heatsink performance. Note that the current should be increased to take into account the fan draw. The required increase in the setting of VR4 can be calculated by multiplying the fan current in amps at 6.8V by the value of R1, which in these LED applications is 0.2W. Typically, it’s about a 15mV increase. In short, be generous with the heatsinking and if the heatsink gets hot during operation, consider using a larger unit. Alternatively, consider adding a fan if you haven’t already done so. Where To Buy Programmed PICs For those capable of doing their own programming, the software (luxeon. hex) for the PIC16F88-E/P microcontroller used in this project will be available for download from our website. Alternatively, you can purchase a programmed microcontroller from SILICON CHIP for $25.00 including postage anywhere within Australia, or $30.00 by airmail elsewhere. Note: it's unlikely that a complete kit of parts will be offered for this project. However, you should have little difficulty buying the parts separately from parts retailers. The PC board can be purchased from RCS Radio. 52  Silicon Chip measure the voltage between TP GND and TP2 and make the final adjustments using VR4 and Table 5. The reason that the test resistor is initially used in place of the Luxeon LED is for safety. If you have made a major mistake that results in uncontrolled current at the output, the resistor will simply get a bit hotter. And that’s much better than blowing an expensive LED – something that can happen in the blink of an eye. As mentioned last month, when the system is switched off, it’s normal for the battery monitor LED to flash momentarily every second or so. Wiring the supply plug If you’re using a plugpack and/or car cigarette lighter plug to charge the Universal High Energy LED Lighting System, you’ll need to wire a 2-pin DIN plug to the power source. In the case of a plugpack, cut off the original DC plug and separate and bare the ends of the cable. Slip the DIN plug cover over the cable, then use a multimeter to determine the polarity of the plugpack output. Solder the positive lead to the smaller of the two DIN plug pins and the negative to the larger pin. Make sure that the connections cannot touch one another – you may want to use some electrical tape or heatshrink around the soldered connections. Finally, slip the DIN plug cover back over the plug and use a multimeter to confirm that the voltage polarity is correct. The procedure is similar for a cigarette lighter plug. In this case, you have to connect a 5A (minimum) figure-8 cable between the lighter plug and the DIN plug (don’t forget to first slip the cigarette lighter plug and DIN plug covers over the cable). Connect the smallest DIN plug pin to the tip of the cigarette lighter plug. The larger DIN plug pin then goes to the side (chassis) connection of the cigarette lighter plug. Conclusion Despite its unassuming appearance, the Universal High Energy LED Lighting System required a major investment in time and effort. The result is a LED lighting system that’s unmatched SC in flexibility and application. siliconchip.com.au