These days it is possible to find an LED (light emitting diode) in any shape, colour and size. This makes them a very good choice as light sources in fursuits and costumes. Whilst inexpensive and low power, it’s not a simple case of connecting these directly to a battery pack. We will show you how to use these devices safely, for maximum LED life and lowest power consumption, which are all critical factors to consider when using them in your fursuit.
Safe operation of Light Emitting Diodes
Firstly, as these devices are diodes, current only flows in one direction. Because of this, they need to be correctly connected to a battery pack with respect to polarity. The anode is always the positive (+) end, and the cathode is correspondingly the negative (-) end. The handy drawing below shows how to identify the anode and cathode leads of virtually any LED you might encounter.
Secondly, an LED is a current driven device. Voltage is not as much of an issue here, but current is, and current limiting is required to safely use any LED. We use resistors to achieve this. Without a resistor, an LED will likely go up in smoke (and the odour of a burnt-out LED is not something easily forgotten or easy to remove from fabrics). A resistor is ALWAYS connected in series with an LED and a power source. Without having to resort to mathematical formulae, we have put together a handy guide of optimized resistor values for given battery pack voltages.
In your typical hardware store, you will generally find wire suited to home appliances. While this will work, it’s often too bulky and thick. A better option is the alarm wire that is used for alarm systems. What you want to do is to buy a few metres of multi-core cable from any alarm equipment or security store, and remove the outer sheath to get the solid, multi-coloured cores within. Now, there is of course a catch: if the wires pass through a place that frequently flexes (i.e. an arm-to-body joint on a fursuit), these wires will eventually snap. For this reason, it is always preferable to use stranded electronics wire, which can be obtained from an electronics or reputable electrical equipment supplier (see list at the end of the article). This wire is typically available in a core area of 0.25mm2, and is very flexible. It is also available in a wide range of colours.
This is a very frequently asked question. As a general rule of thumb, you need at least 3 volts, as the LED needs that potential difference to ensure conduction takes place in the semiconductor crystal lattice. Therefore I normally say that one should begin at 3.6V. This voltage is a typical voltage provided by Li-ion battery packs, which are lightweight and very powerful. The trouble is that, unless a proper (certified) charger is available for the battery you use, a Li-ion polymer battery is a very dangerous item, one that could potentially burn you, or cause catastrophic damage to life and property. Short-circuiting these batteries is a similar hazard. Therefore, unless you’re using the services of a qualified electronic engineer we recommend you use off-the shelf alkaline or dry cells with a battery box. We are aware the dry cells are bulkier and heavier but we value your personal safety more than anything. We don’t want to see furs catch alight.
For LEDs, I usually recommend using a pack of four D-cells, giving a voltage of 6 V DC. You can of course, depending on your situation, even use a 12V lead-acid gel battery (if you can handle the weight and your suit has the space), but I think for most applications we will see folks using the torch cells. Torch cells are somewhat bulkier than pen cells. The size has to do with capacity. What you need to do is decide how many LEDs you want to run from a given battery pack, and scale that accordingly to your needs.
The advantage of using cells is that they can be replaced with rechargeable cells of the same size, and this will then cut down on the cost of having to purchase cells all the time. The table gives you a rough idea of how long one LED will run from a given battery size. Of course with multiples, this is divided accordingly.
Connecting the LED to the battery
To make the LED work and emit light, the LED, and accompanying resistor, is connected to the battery as shown. The resistor can be close to the LED, or close to the battery, as long as the wires between are not too thin and not too long.
Connecting more than one LED
In most every case it is desirable to use more than one LED, and this then becomes a question of how many versus how big the capacity of the battery pack. More LEDs to power means less battery life. A compromise point has to be reached. Generally I recommend each LED has its own resistor and each LED (with resistor) is connected in parallel to the battery box. “Why not in series?” you might ask. Well the reason is that each LED in series means the voltage across the entire string begins to increase as you add each LED. Eventually you will need as high as 15-20V to get the LEDs to light up, and I am sure that you don’t want to carry that many batteries in your tail.
With the sheer proliferation of LED types out there, it’s a very practical proposition to use them in fursuits and costumes. This article hopes to give you enough information to begin using them easily, and most of all, to have fun. To get you started, here’s a list of suppliers of LEDs, resistors, battery boxes and suitable wire (All are enabled for e-commerce and ship to anywhere in in the Republic).
- Communica: 53 Landmarks Ave, Samrand, Centurion, 0157 (012 657 3500) communica.co.za
- Mantech: 32 Laub Str, New Centre, Johannesburg, 2000 (011 493 9307) www.mantech.co.za
- DIY Electronics: Unit 6, Northmead Industrial Park, 10 Moreland Drive, RedHill, Durban (031 313 4701) www.diyelectronics.co.za
- Yebo Electronics: 50 Washington Str, Boston, Bellville 7530 (021 949 1999) www.fort777.co.za
- Hobbytronics: Milkwood Avenue, Lovemore Park, Port Elizabeth. (041 004 0400) www.hobbytronics.co.zaleeworksgear