Pwm to resistance converter

Also, presumably, you are wanting to feed this sensor into a computer based instrument, which probably requires a steady voltage. From what you've already said, presumably the new instrument requires a resistive sensor, which forms a potential divider with an other resistor?. Assuming the requirement is something similar to that, presumably you can't alter the sensor? If you can you only need the lowpass filter, you could then feed the resultant volage directly in - no need to try and convert it to a resistance.

The lowpass filter could consist simply of a resistor and capacitor, depending on the output impedance of the sensor, and the input impedance of the unit it will be feeding. With a microcontroller uC you can measure the width of the pulse directly without an A to D.

Look for a ucontroller with a "capture compare" module. This extra hardware built into the uC will let you time the pulse width without much software oversite. The uC then uses a digital pot to set the resistance. Ron's solution doesn't involve a uC but by using a uC you don't have to use any analog components besides your digital pot which will make it less noise sensitive.

You will also be able to have any relationship between input pulsewidth and output resistance that you want. You also might be able to make the uC talk to your automotive bus CAN etc. Your switching method might work too. Hope this helps Brent. Similar threads D. Replies 15 Views 2K. Jan 24, drkidd Replies 2 Views 1K. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

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Viewed 7k times. Jinkyoo Park Jinkyoo Park 45 1 1 gold badge 2 2 silver badges 6 6 bronze badges. Add a comment. Active Oldest Votes. This article briefly summarized a simple method for converting the output of a PWM sensor to an analog voltage. The methods shown use a fairly straightforward method for designing a filter as well as documenting the caveat for using the simple method. The primary goal of showing how to realize a passive low pass filter was illustrated with a first order filter, and a second order filter.

The reader can extend the order of the filter in order to increase the response time of the signal while maintaining acceptable ripple. The worked examples show that unless a very slow response time is acceptable, most typical applications will want to pursue a second order or higher low pass filter in order to keep the filter response fast enough, and to maintain the use of small components.

Increasing the order of the filter increased the number of passive components required to realize the filter. In this case, we went from two total passives to realize a first order filter, to four total passives to realize the second order filter. Although every system is different, the methods in this document can be used for many different systems.

By using the equations documented above, a filter can be designed around a different system. In closing, with a little bit of creative filter design, an off-the-shelf PWM output sensor can be designed into a system that requires an analog voltage. The information contained in this document does not constitute any representation, warranty, assurance, guaranty, or inducement by Allegro to the customer with respect to the subject matter of this document.

The information being provided does not guarantee that a process based on this information will be reliable, or that Allegro has explored all of the possible failure modes. Current Sensors. Current Sensors Innovations.

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Cooling Systems. DC-DC Converters. Engine Cooling Fans, Pumps and Compressors. Please see my sample below. I think you're just slightly misunderstanding the example in the docs. Try this just replace the red text with the specific pins from your circuit. Remember that when you read an input it doesn't give you a voltage.

It gives you a value between 0 - So you are taking a value between 0 - and translating it to a value between 0 - with map and then writing this to a PWM pin. Thanks for the help. How do I direct it to read the Aref pin, or can I use an Analog input pin, such as ?

Connect the 0 - 5v input to analog pin 0 A0. Voltage to resistance digital pot or PWM? Forum read only Hardware Interfacing.