| Electronics > Projects, Designs, and Technical Stuff |
| Digital Caliper with custom plates? |
| (1/5) > >> |
| q12:
First, I am a hobbyist in electronics for 20 years. I am not professional, but not a rookie either. :-DMM - Digital Caliper. I google about how it works and they say "it use a capacitive sensor to register the measurement". Here is a quick and dirty explanation of the principle: https://www.wonkeedonkeetools.co.uk/calipers/how-does-a-digital-caliper-work/ I want to be able to make the 2 'sensors' as long or wide as I need. And by 'sensors' i mean the 2 sliding grid plates. And connect them to the existing electronics. Practically, I want to put new (customized) plates + corespondent wires. I want to know if I can build these plates myself. Can someone make a sample or give me an answer on this matter? What should i pay attention to? Also, i may add, i want to make it and put it on my lathe for traveling cariage - wich is pure mechanical at this point. I dream over this little gadget for a couple of years to have it. Thank you and i hope you can answer. |
| ataradov:
The problem with making them yourself is holding the accuracy and tolerances over the entire length. There are DROs with sensors of any length you like. And while they may seem to be expensive, it would be much more expensive to actually make this stuff yourself. And also, good calipers use a combination of inductive and capacitive sensing. And the rails for that are a bit more complicated. |
| rhb:
The Chinese make DROs using the same technology as digital calipers and the prices are quite nominal. The readouts are separate from the sensor. But they are not glass scales, so the temp co will not be as good as the professional DROs. Here's one seller: http://www.grizzly.com/search/?q=(categoryid%3a240480) And lots of people just modify a cheap DRO. That is especially true on the smaller mini-lathes. Though the readout is not as convenient. |
| q12:
thank you mister ataradov; The basic idea that i think of, (and feel free to correct me if im wrong) these plates are just simple copper prints over the isolator board, and all that they have special, is their shape with specific height/width and probably thickness too. And thats it. If i can replicate their form and position, (let's assume) scratching a blank electronic board, it must do it's job most probably. And only for the 'fixed' part that is the longest. The mobile part that is on the reading device, that I can leave it alone and just use it. Make a smart assumption. Philosophy a bit on the subject. I need ideas, especially from someone who have more experience in electronics in general. Think like you would do it for yourself. The cheapest and dirty you can make it, just to prove it works. The finer calibrations i will have to fight with myself. - thank you mister rhb; your idea with DROs is to be kept as plan B if plan A will fail miserably. -- But I am EXTREMELY passionately curious about the functionality of the sensor itself. Can you (guys) make me a cheap and dirty schematic + explanations for a functional electronic meter/scale ? The actual reading device (probably with a PIC16f84) or some demultiplexors or just led scale or a needle ... can be made after I get some sort of reading from the sensor itself. By the way, I will read (mili) -Volts or Amperes from the output sensor? Or (mili/micro) Farads or Resistance? That's why i came with this question and I really need some clarification. Please make a good case. For science and progress. |
| q12:
I responded alone (with ataradov help actually) to my own question by searching a bit more harder on the subject. I found this relevant page: https://en.wikipedia.org/wiki/Capacitive_sensing It turns out that [Capacitive_sensing] is the contemporary technology that is widely used all around. Measuring and today touch technology. I didnt put too much thought into it. Until today >:D The most important information for me from this page is this: "Capacitance is typically measured indirectly, by using it to control the frequency of an oscillator, or to vary the level of coupling (or attenuation) of an AC signal. " ataradov mentioned that: "good calipers use a combination of inductive and capacitive sensing"- wich complicates things indeed. I had no idea about capacitive sensing until today (not seriously i mean). But you specified "good calipers" - i want a cheap /concept proof solution for myself. My next step is to try to imitate as best as i can the [fixed plate] markings. If you have any helpful suggestions, please tell. |
| Navigation |
| Message Index |
| Next page |