I'm working on a project to create a heated scarf for my sister. She gets cold when she's sitting at her computer (laptop) all day and I want to make something that she can drape over/around her neck and shoulders. For convenience I'm planning on using her laptop PS to provide the power; when she's cold can can unplug the laptop and fire up the heated scarf. To control the temperature I'll hook up a simple PWM in between the PS and the nichrome wire.
The PS is 19.5v and 6 amps. I will use nichrome resistance wire with a total resistance of 6 ohms; if I understand the calculations correctly this will result in ~65 watts of heat, well below the PS's rating. Do you guys have any thoughts on the feasibility/dangers of this project? Here are the concerns that I can think of:
The PS is 19.5v and 6 amps. I will use nichrome resistance wire with a total resistance of 6 ohms; if I understand the calculations correctly this will result in ~65 watts of heat, well below the PS's rating. Do you guys have any thoughts on the feasibility/dangers of this project? Here are the concerns that I can think of:
- Will this damage the PS at all? I can imagine that generating a PWM signal from a PS that is designed for steady current could be a problem.
- I'd like insert a fuse between the PS and the PWM controller. Do you have any suggestions for what would work well? (Or even if it's necessary?)
- My guess is that the biggest concern outside of the PS is making sure the nichrome wire doesn't short and allow a much bigger current draw.
- Do you think a wool scarf is heat-resistant enough? I plan on folding over the scarf and sewing two channels for the wire to run through.