Hello,
I have a set of old (and rare) mechanical automotive gauges that are missing their sensors. I have been looking for a way to repair them, and have not found anything. So now I am looking into modernizing them with electric sensors and stepper motors controlled by either an Arduino Mini, Micro, or Nano. I am not all too familiar with the capabilities of the different models. My questions are:
Which main board is the smallest, yet still capable of taking input from a temp sensor and giving output to a stepper motor?
Aside from that, another hurdle is that the gauges are not a linearly scaled sweep, i.e. it is not a set amount of degree's per step (See attached image for clarification). Is it possible to accurately accomplish this?
Converting digital values can be done by using an index table.
Suppose You use an analog input. Then make a table of 1023 cells, each cell containing the data You need to make Your stepper point where You want. Just let the A/D value point into the table.
When comparing the mini, nano, and micro the difference is mainly how many inputs and outputs they have. But an important detail is that mini does not have analog inputs which you might need depending on what you are trying to build. For small projects the nano is probably what you will want, if you need a few more analog inputs the micro will be what you want. Overall the micro and nano are extremely similar in every way except the chip they use and their number of analog inputs. But you will find that the nano is slightly smaller. For some in depth reading check out this link .
As for the other part of your question I can't see the picture.
bryang078:
I see you have alligator clips attached to back of the sensor. Does this sensor produce an analog voltage that is then read by a sensor?
The alligator clips are to the backlight of the gauge. The gauge itself is strictly mechanical, using a metal coil similar to an old school thermostat.
Do you have a diagram for the car/dial/sensor, and do you know the value/resistance of the missing sensor.
Could just be an NTC to ground, with a standard value.
That NTC can be replaced with a mosfet switch (PWM) to ground, with a series protection resistor in the drain.
Linearity is the least of your problems. That can be solved with code.
Leo..
Wawa:
Do you have a diagram for the car/dial/sensor, and do you know the value/resistance of the missing sensor.
Could just be an NTC to ground, with a standard value.
That NTC can be replaced with a mosfet switch (PWM) to ground, with a series protection resistor in the drain.
Linearity is the least of your problems. That can be solved with code.
Leo..
It's originally a mercury sensor, no electronics involved
Looks like a capiliary tube meter in which there would be all mechanical "bowden tube" and segment gears.
If you are looking at stripping the guts out and replace with electro- mechanical, I did a similar thing using a mini servo attached through step-up gearing on the back.
Servo was scaled in program to give desired output for readout and completed guage had a scale diameter of 20mm.
Used a picaxe then but a bit simpler as scale was linear so Arduino may be better choice.
Used 0-5v for a tacho readout to 270 degrees. With picaxe about 10 lines of code.
bluejets:
Looks like a capiliary tube meter in which there would be all mechanical "bowden tube" and segment gears.
Yes, upon some research you are 100% correct. So basically, with some programming and the proper modern sensor, this is entirely doable. Good, that's what I wanted to know before I purchased the stepper motor and arduino.
