is frequently used for such prototyping. One that can visualise the
temperature of the parts would make the engineer's job slightly easier.
When prototyping electronics, sometimes a part gets overloaded and the [link?:magic smoke] leaks, rendering it nonfunctional. If such event is not instantaneous and the heating progresses for longer time, this can be easily missed, the engineer is lulled into false complacency and ruins a part and/or burns his fingers.
A solderless breadboard is frequently used for such prototyping. One that can visualise the
temperature of the parts would make the engineer's job slightly easier.
A solderless breadboard was chosen, and cleaned with tetrachloroetylene. (Acetone
or any other solvent would do the job too.)
A set of three microencapsulated leuco-dye thermochromic pigments
with different threshold temperatures and compatible colors, was obtained:
The thermochromic composition, same as in the Thermochromic Silicone
,
was used, with the same epoxy binder as in the Thermochromic Kitchenware project.
The resin was highly viscous, making the applied layer uneven. Heating with a hairdryer lowered the viscosity
somewhat, slightly alleviating the issue.
 Clean breadboard |  First coat, hairdryer-heated |
The cured coating was tested with a power resistor. It was shown that the uneven nature of the coating together with the rather low thickness and color intensity made the color change somewhat less obvious than desired.
The high ambient temperature of the summer day made brought the board above the first threshold, rendering it purple instead of black.
 First coat, resistor heat test |  First coat, resistor heat test |  First coat, resistor heat test |  First coat, resistor heat test |
A second coat of the paint, with slightly higher pigment loading, was applied. After cooling in the fridge for a couple minutes it shown a nice even black color.
 Second coat |  Second coat, fridge-cooled |
Two tests were done with power resistors, used as test sources of heat.
 Resistor test |  Resistor test |  Resistor test |  Resistor test |
 Resistor test |  Resistor test |  Resistor test |  Resistor test |
 Resistor test |  Resistor test |  Resistor test |  Resistor test |
A part can heat the board by direct contact and by heat conduction through the leads, but also by the thermal radiation.
 Resistor test |  Resistor test |  Resistor test |  Resistor test |
 Resistor test |  Resistor test |  Resistor test |  Resistor test |
Many of the little holes were plugged shut by the resin, or made slightly smaller. They were enlarged again with a 1mm drill bit.