heat generating circuit with 9v battery

[sawadeejar]

Dear all,

Anyone has an idea how to build heat generating circuit with 9v battery?
This schematic found at http://www.kobakant.at/DIY/?p=2909 using 24v supply. I wonder how to modify it to work with 9v instead of 24v power supply.

Thanks.

[pebe]

What sort of 9V battery?
How much heat to you want to get from it?
Can you not use a switch?

[sawadeejar]

What sort of 9V battery? How much heat to you want to get from it?

My first plan was to use PP3 V9 battery but I've realised that it's not powerful enough to create required heat 15 - 40 c degree. Note: the heating element is conductive thread (12Ω/foot)

The circuit will be embedded in clothing so the power source should be lightweight and portable. What type and voltage of battery would you recommend?

Can you not use a switch?

Can you explain more on this option please?

[pebe]

The battery with the largest output for its weight is probably the Li-Ion battery as used in mobile phones, etc. I don't know what voltage or capacity you need because I know nothing about this heating thread.

Re. the switch option, I noticed the circuit you were considering went to great lengths to switch on power to the thread stuff, and wondered why you did not use a simple on/off switch.

[sawadeejar]

Re. the switch option, I noticed the circuit you were considering went to great lengths to switch on power to the thread stuff, and wondered why you did not use a simple on/off switch.

I've planed to use switches as seen in the attached picture. Each switch is waiting for the controller to trigger so 1 heat circuit can be used to supply heat to multiple threads at the same time and different time.

Is this a good plan?

[pebe]

You have four manual switches. How do the outputs from D1-D4 do any switching?

[sawadeejar]

D1-4 outputs will be controlled as high or low. High --> turn ON, Low --> turn OFF.

[pebe]

Your outputs from D1 to D4, going to the output of the heat controller and feeding all of the manual switches connected together makes no sense at all.

[sawadeejar]

You are right.
Is there a way to control each heating element separately?

I only can think of using 4 heat circuits connented to the microcontroller.

[pebe]

What does the Heat Controller do?

[sawadeejar]

To generate heat.
I think that it's needed because i also want to control the temperature at certain degrees.

[pebe]

So what is it supposed to do? How is it supposed to control the switches?

[ttom]

Circuit to sense the voltage and it's zero crossing