The $0.40 DAC has a i2c interface, so it's designed to interface with a controller if you need something beyond simple alarm tones.

Thx for the info, but there's no audio in this system. The DAC described in this thread is just for slowly changing data, sample rate about 1 Hz. This DAC will not be used for audio.

The audio is in a separate, external system, which is outside the scope of this question.

Thx!

 

Thx for the info, but there's no audio in this system. The DAC described in this thread is just for slowly changing data, sample rate about 1 Hz. This DAC will not be used for audio.

The audio is in a separate, external system, which is outside the scope of this question.

Thx!

So what, you still need to program and talk to the DACs you linked to via i2c even to set DC levels.

 

So what, you still need to program and talk to the DACs you linked to via i2c even to set DC levels.

Sorry if i misunderstood your comment. Are you saying there's a reason that $0.40 DAC43701 won't work for my requirement? I understand i need to talk to the DAC via I2C. The I2C data will be emitted by an external controller, which i will design separately. This question is just about the DAC.

Fyi, i need to compare a current to an external reference current. The reference current must be isolated, so i plan to use either a frequency-reference with F/V, or a binary-reference with a DAC.

 

If you wind up with more than two chips, a micro would likely be cheaper, smaller and simpler, even if it does nothing more than what your several chips do.

I think this will be the cheapest. I think the sensor and comparator will be analog. Do you see a way to make this cheaper/simpler with a micro?

If it needs a microprocessor than an A/D comes for free these days.

Microcontroller?

Thx!

 

You apparently are going to use a microcontroller already since you said

The I2C data will be emitted by an external controller, which i will design separately.

What is this external controller? If it is a microcontroller with an ADC, you don’t need any of the external hardware. Just measure the current with the micro’s ADC and compare it to the value you intend to send out to the DAC. Okay, you do need a resistor to convert the current to a voltage.

 

You apparently are going to use a microcontroller already since you said
What is this external controller?

The external controller is not available to perform any duties in this current comparator. There's only one data-connection available between the external controller and this current-comparator, and no analog connections available. Take my word for it.

You want to make audio

I don't want to make audio.

Cheers!

 

Okay. A small micro would cost about the sane as the DAC plus comparator that it would replace.

 

Okay. A small micro would cost about the sane as the DAC plus comparator that it would replace.

Thx. I think you're suggesting to use the uC's ADC to convert the current sensor output to digital, and then compare that to the binary reference, correct? This does seem like the cheapest solution.

 

i've devised a new solution, so i don't need F/V, DAC, ADC, or a uC.