I would like to control and power a 40x40mm size array of 25 x 25 small heating elements which should function just like a visual display of LEDs, but switching heating elements on/off instead. I am thinking of using tiny strips (<2mm square) of 28-30 AWG nichrome wire. And I would like to use an Arduino to drive the matrix of wires. Each nichrome strip needs to reach temperatures between 30°C to 45°C in the air. Power source can be 1 x Li-Ion Polymer battery OR 2 x Li-Ion 18650 (2300mAh) cells.
but need the following advice:
- Would SMD themistors be suitable instead of resistive nichrome wire?
- Can I provide the Nichrome wires with sufficient current through using a multiplexor? or must I use relays to power them directly?
- How does cooling nichrome wire (drawing heat via conduction to lower temperature) compare to less resistive wires? does this require less or more power?
- What are some suitable multiplex shields or other methods of controlling them with an arduino?
- Would Nichrome sheet be able to be chemically etched just like laminated copper boards?