In most of the under developed nations, access to basic health care is scarce. A heater is an indispensable device for many applications, especially for medical purposes. As such, a simple and easy to make heater from readily available materials becomes valuable equipment to help alleviate the human health problems. An ultra low cost (total cost including materials and manufacturing is less than a dollar per heater) heater from readily available materials like paper/cellulose acetate sheet and a pencil was designed and fabricated. Manually, using high graphite contained pencil; paper/cellulose surface was arbitrarily coated by applying numerous pencil strokes on the surface. Contacts were connected using either a wire or Copper/Aluminum foils over the coated surface. Power was supplied using 0-12VDC adaptor or similar range batteries. Maximum temperature attended by the heater was around 140 ºC. Applied pressure through paper binder clips, self adhesive tapes or rubber bands provides the ohmic contact required to supply power throught the heater. This makes the heater highly tunnable in terms of size, power supplies and ergonomic for therapeutic applications. From the prospetive of materials used, the heater has shown long lasting repeatability in the temperature range of 100 ºC -110 ºC.
Since the entire fabrication of heater cost dirt cheap, its large scale fabrication is not at all a concern. With little or no training, fabrication of this heater can be done by anyone. The main application of this heater was explored in the laboratory, commercial heating source and therapeutic uses. The heater is fabricated in a crude manner by mechanical abrasion of graphite composite from soft grade pencils. The temperature attained with this heater was in range of 40ºC-140ºC with varying input power. The heater was successfully implemented in applications like substrate heating, chemical reactions and has potential to be used in all application demanding higher temperatures in range specified.
Additionally, using graphite composite films, flexible heater on cellulose acetate substrate (Overhead projector (OHP) transparency sheet) was constructed and further used in therapeutic applications. The entire heater assembly was also tested using battery and the performance was identical as in case of power supply indicative of portability feature. Use of substrate is not limited to the paper or OHP transparency sheets. Practically almost any surface on which pencil marking can be made is of potential use for making heater. The design is very simple and above all it is technically easy to fabricate directly on the field for its respective domain of applications. For an amateur to get from design to fabricate a real time working device, it takes less than half an hour, which also includes time taken for the procurement of the materials. Our results provide an economically viable yet effective heater fabricated through a simple and fast fabrication process without any need of high tech instrumentation and ambient conditions.