Wednesday, January 30, 2013

PWM

For an upcoming modification to the central heating I need a controller capable of outputting a (standard?) 0 to 10V control signal.

Of course, this is a job for Arduino/Jeenode, and not for some store bough industrial controller.

Since the JeeNode works at 3.3 volts,  I set off to build an amplifier, using an LM358, wired to multiply the input by 3 times, which gives a nice and convenient range of 0 to 10V!

I am still in the process of building the circuit, but for this I needed to get the oscilloscope out.

Once I had the work on the breadboard ready I captured the following images, I thought they were nice.
video



I wanted to have both lines in the same shot, but my channel B is not working well, so I can only use one channel of the scope.

After I shot these, I proceeded to blow up an LM7805 (why does it have a different pinout from the LM78L12) and consequently blow up my old trusty JeeUSB version 2...I hope I can bring it back to life.

Just a short mention of what the project comprises: 0..10V controller for a 24V ventilator fan, and two Dallas 1820 measuring the temperature of the water flow (in and out). The motor will be controlled based on these.
Soon the circuits and protoboard pictures, later custom PCB's?

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