Step by step instructions for how to build and implement the replacement surgical lamp bulb system using an LED circuit developed by Mohammed Shafir and Zoe Englander as part of the course BME 262-Design for the Developing World at the Pratt School of Engineering, Duke University.
This system will provide a low cost and long lasting replacement for hard to acquire surgical lamp bulbs in the developing world. These instructions explain how to use the replacement bulb system with components and tools included in the kit.
Devices in the developing world that require light bulbs to perform their function are of crucial use in providing medical care. However, a major problem with the use of these devices in the developing world is that once the light bulbs break or burn out, the replacement bulbs are very expensive or difficult to acquire. Thus, many devices that are completely functional otherwise are not being used because they lack working bulbs.
One critical medical device that is afflicted by this problem are surgical lamps used in the operating room. These lights are of critical use to the surgeon in illuminating the area of interest during surgery. The absence of these lights seriously hampers the surgeons' ability to make informed decisions and also restricts the performance of surgeries to intervals in the day when there is sufficient light to illuminate the room.
We have remedied this problem with a replacement bulb system that will allow the user to replace conventional light bulbs in commonly used surgical lamps with a new illumination system composed of Light Emitting Diode (LED) bulbs. LED bulbs are much more efficient than conventional tungsten or halogen bulbs, consume less power, are more rigid (due to the absence of moving parts) and also have a much longer life span. Therefore, the LED illumination system will have much longer lifespan, be less expensive to run, and will not break as easily. The LED illumination system will only need to be installed once, and will not need to be replaced for many years.
In addition, this system is compatible with many different types of lamps, with a variety of different light bulbs. This system utilizes the original light bulb base, so the circuit can be made to be compatible with almost any size and shape of light bulb. The system will work for any lamp that uses between 7 and 24 volts DC.
Step 1: Parts List
The parts list for this design is shown in the table below. Additional parts and tools necessary for the construction of this device are:
1.) A blank PCB board
2.) Thin connection wires
3.) A hammer
4.) Soldering iron
5.) Soldering wire
6.) Krazy Glue
The National Semiconductor LM3404 1.0 Amp Constant Current Buck Regulator is used as the current regulating device. A detailed set of instructions can be found in the data sheet for this device. By following these instructions, the circuit designer can determine the ratings of the external components needed to meet their needs.