DIY lighting bar for a music stand

A while ago I started going to an open-mike night (for musicians), and noticed that a few people (myself included) had trouble reading the music under the low lighting levels in the room, and nobody really liked switching on the very bright room lights.  Looking at existing solutions I observed that:

Clip-on music lights were often tiny (many are advertised with a photoshopped picture which seriously over-exaggerate their size), barely managed to illuminate two pages adequately (some didn't manage one page very well), and some have a weird colour to them that is hard to focus your eyes on.  If you are buying the clip-on ones that look like two insect antenna on flexible stalks, look for ones with lenses over their lights, they spread the beam out better.  But most didn't clip on well, and often get lost.  Or get taken home by the wrong person (name your gear, people; it won't stop theft, but it does solve the who's owns what dilemma when packing up).  Some use disposable batteries, which eventually can get expensive, and is obviously wastefull.

There are some ludicrously expensive music sconces (e.g. $300).  But it's hard to justify that price for amateur purposes, or even for professional purposes, especially if you need to buy several.  And some are ridiculously large (so you need a heavy-duty music stand, too).  Traditional ones require mains power, so you have more leads (and tripwires) to deal with.  Not to mention that you get hemmed into staying where things were put, even if it's not that convenient.

My idea was to build something like the lightbar I built for my piano stand (for the same reasons, while playing at this open-mike night).  Lightweight, battery powered, reasonably robust and idiot proof, and easily repairable, using parts I can buy from the local hardware and electronics shops, and will stay attached to the stand.  And for people to able to pick the stand up and move it around without having to deal with cables, so you use the stand the same way you've always used a music stand.  Of course you can plug into a mains power supply adaptor, if you don't mind being tied to a spot.  And being low-voltage means you can customise it to your heart's content without the risk of electric shocks, nor running afoul of unlicensed electrical work regulations.  I ended up with something that was better at illuminating the sheetmusic than the other music lights I'd seen—I engineer things to do a job well, not just scrape by with the bare minimum.

I cut a section of square U-section aluminium strip to a suitable length to fit the width of the music stand and cover at least two A4 pages on the music stand.  It comes in different sizes, and I picked one that's just wide enough to fit LED tape inside it (which is usually 1 cm across).  Because of the overspill, it will adequately light a three page score overhanging the edges of the stand, but you can always oversize the strip to begin with.  I often use two- or three-page scores to bump the size of the text up, and unroll complex jumps and repeats into straight-through scores for ease-of-reading.  Cutting it to size was just a few minutes work with a hacksaw, and files and sandpaper to smooth off the edges.  The U-section aluminium directs the light where you want it, and stops it glaring into your eyes (and other people's), when angled to illuminate the page nicely.

Then I glued some LED tape inside it.  There are self-adhesive LED tapes, but the stuff I was using wasn't.  And put some translucent packing foam (the squishy stuff) into the gap to diffuse the lighting a bit more.  If I wanted to get really fancy, I could have cut the foam wedge-shaped, so it blocked more light at the top of the page than the bottom, compensating for the differing distances from the light.  Though I imagine getting that right might be harder in reality than in planning.  The foam diffuser isn't needed with LED strips that are already diffused, or have their LEDs very close together.  Some of the dimmer ones have few LEDs spread far apart, and the sparseness of them is the first clue as to whether they'll be bright enough to use (they're more for decoration than illumination).

LED tape can be cut to length, it's marked with breakpoints where you are supposed to make any cuts.  Don't worry too much about cutting the tape an inch or so shorter than you wanted, enough light will spill out sideways past the end of the tape.  The breakpoints have solderpads for attaching wires, slotting into connectors, or joining sections of LED tape together.  Some simple LED tape can even be cut between those points, but you won't be able to join it back together, and you may find that some LEDs won't light any more if they were part of a series group of LEDs wired together.  Since this is being stuck inside metal, put some insulation tape on the metal under the edge of cut LED tape (the adhesive backing on LED tape isn't thick enough to ensure the copper solder pads are insulated from what it's attached to.  You may even want to slightly curl the edge up, so it doesn't have a sharp edge edge cutting down through the tape.

The plan was to power it directly from a basic USB rechargable battery bank, so I used 5 volt LED tape.  Some battery banks can supply other voltages, but they can all supply 5 volts without having to do anything special.  Most battery banks will probably power these LEDs for many hours continuously (my cheap, six year old, ones certainly do).  These days, much larger capacity battery banks are available for around $25.  Operating-time-wise, battery banks last longer than disposable batteries, and it's not long before it's a cheaper way to do things.

LED tape comes in many varieties.  There's different operating voltages, colours, and dumb/smart versions.  Dumb versions are all you need, they just have LEDs directly powered from a single voltage, and will usually survive accidental reverse voltage (this is handy when you're experimenting and make mistakes).  Smart ones have flashing functions, and colour changing features, etc.  You don't need that, you end up with something that requires a controller to turn them on and off, becoming more complicated to use than is necessary for the job.  Also, reverse voltage tends to be fatal to them.

The chief choice that may concern you is warm white or cold white (blueish).  You may decide to choose whichever is the same as your room lighting; or, you may consider that your eyes expect warm white at low reading lamp light levels (and it tends to be easier on the eyes), versus them being geared towards cold white at bright daylight lighting levels.  Also worth considering is that many people find blue the hardest colour for their eyes to focus on (it's to do with how light goes through the optics in your eye), so warmer colours make things easier.

Another consideration is brightness.  Dim lighting can be an eyestrain, and excessively bright lighting in one spot (your illuminated music) makes for sore eyes.  Also, brighter LED tape is more expensive, and will also flatten batteries quicker.  If you can't find suitable brightness LED tape (not too dim or too bright), then soldering one or more diodes in series with the DC supply wiring will dim bright LEDs down.  Yes, you could use a resistor, but you'd have to calculate the value for your current use, and pick one able to handle the wattage.  A diode will drop the voltage by 0.6 volts, and an ordinary 1N4007 can handle the amount of current being used here just fine.  You can buy LED tape in long lengths on a reel, or shorter lengths (which is usually more expensive per metre, but may be cheaper, overall, though having extra may be useful for other projects).  I ended up buying a ready made flexible camping light, and removing the LED tape from it.  It was the cheapest option at the time, and the only one bright enough, too.

Since most battery banks don't have an on/off switch, and neither does the LED tape, I fitted one in the middle of the cabling.  A switch is more useful than scrabbling around plugging and unplugging USB connectors, and USB connectors aren't long-living as you'd like them to be.  There's nothing special about wiring a switch into this circuit, it just has to interrupt one of the DC wires between battery and LED, though it's traditional to switch the positive line.  I used an old-school style of desklight push switch.  They're easy to switch on and off from any position, are a comfortable size to press with your fingertip, reasonably impact resistant, and not likely to damage anything that they knock into.

There's a bit of packing, glue, and heatshrink, to provide some degree of protection to the join where the cabling is soldered to the LED tape.  The cable from the light bar goes to the switch fitted in a small plastic box, and a USB lead goes from the switchbox to the battery bank (I just cut one end off a cheap USB lead, used the positive and negative DC wires in it, and cut off the remaining data wires and shielding at different lengths so that none of them can touch each other).  The cables were cut to lengths where they are long enough to be able to attach and remove everything from the music stand without yanking on any connections, and short enough that they can be clipped into position with adhesive plastic hooks and kept out of the way.

It pays to use a meter on the sacrificial USB lead to check which are the correct wires.  On the USB A connector (the rectangular type, like on mice and keyboards), the outer pins are the supply pins, with the inner pins for data.  Traditionally the positive voltage would be a red wire, and the negative voltage (or really zero volts, in this application) would be a black wire.  But Chinese manufacturers are infamous for doing that backwards.  I would check which wires actually do connect to the outer pins, and check their polarity when plugged into a power bank.  There are several different kinds of USB connectors, but the old rectangular one is cheap, reasonably robust, found all over the place, easy to work with and wire up for a 5 volt supply.

This switch box was fitted attached under the edge of the music stand (out of the way of normal use of the stand, and easily reached from either side of the stand—by the performer or any roadies).  Preferablly I'd screw the box to the stand, but we didn't want to modify the stands in any way, so we'll use velcro or adhesive tape.

To attach the lightbar to the stand, I picked two eye-bolts where their eye was big enough to thread the aluminium U-strip lightbar through it, and the width of the bolt is nice and strong (M10).  The size of the eye is tight enough to hold it in place, but still let you rotate the lightbar into the right angle.  Larger eye diameters would need some packing around the lightbar to stop it moving out of place.  And bolts were chosen that were long enough to hold the lightbar a reasonable distance from the sheet music—this means you get more even lighting down the whole length of the page.  Again, we didn't want to modify the music stand, so it's bolted through existing holes in the stand, with oversized washers to grip onto it well and spread the strain across a wider area.  I used wingnuts on the back side, so no spanners are needed.  If modifying the stand was an option, I would have drilled a couple of mounting holes a bit closer to the top of the stand.  But as long as you angle the music rest to read the whole page normally, for whatever height you raise it, the lightbar is out of the way.

If you have music books where you need to turn pages as you play, it is better to ensure there's more of a gap between the top of the pages and the eyebolts.  A solution to raising the light bar further up the stand is to bolt two metal struts to the stand in the same way I passed the eyebolts through (but using dome headed bolts, to minimise their protrusion), so the struts extend over the top, and then mount the eyebolts through them.  The need for this depends on the height of your music books, and the music rest.

The battery bank has been attached to the back of the stand with adhesive velcro, behind the music, so the stand height can be adjusted in the normal way without worrying about any cables.  There are plenty of velcro products that have good adhesive, I've had some on the side of my video camera that's lasted some 15 years of use without letting go.  An alternative would be a small pouch fastened to the music stand.

I probably spent a couple of hours building one, as I experimented with different approaches to it.  And I built a second one in far less than half that time.  I would have spent more time getting all my parts and tools organised than doing the actual work.  All the parts I used cost about $33 in total (eyebolts, aluminium bar, LED tape, switch, plastic box, sacrificial USB cable).