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I/O Devices - Sensors - Modules
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Topic starter
2022-12-16 7:11 pm
@zander Ron, my understanding is essentially the same as yours with one difference. As I understand them, Hall switches pull the pin to ground when a magnet is brought into range producing a falling voltage. The pin stays low until the magnet is moved out of range at which time there is a rising voltage. This way the interrupt isn't kicked off multiple times for one encounter with the magnet regardless of whether the interrupt is set to falling, rising or changing.
As always, someone please correct me if this is wrong.
2022-12-16 7:21 pm
Why do you assume that you can ignore bounce, or do you handle that in code ?
Anything seems possible when you don't know what you're talking about.
Topic starter
2022-12-16 7:23 pm
@zander Hi Ron, I would be glad to when it's finalized - if ever.... 🤣
The original project was "inspired" by the YouTube video below. As usual, I thought I could adapt it to my needs and do it better. 😆 😆 😆 😆 He has several videos of various iterations of his project. His is designed specifically to mount a camera and slide along a rail while keeping the camera aimed at a specific point in space. From his videos, it appears to work great. Me, I'm a woodturner, and my club hosts demonstrations each month, and an overhead camera is almost a must. However, cameras in that position are difficult to adjust w/o disrupting the demonstration, so my goal is a remotely controlled camera mount that will slide, pan, tilt, and zoom.
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Topic starter
2022-12-16 7:28 pm
@will Hi will. I'm planning on using a belt. This mechanism will need to travel around three feet, possibly a little more. I figure a lead screw that long could be hard to find.
2022-12-16 7:32 pm
Ron Bentley
Creativity is an input to innovation and change is the output from innovation. Braden Kelley
A computer is a machine for constructing mappings from input to output. Michael Kirby
Through great input you get great output. RZA
Gauss is great but Euler rocks!!
Topic starter
2022-12-16 7:34 pm
@ronbentley1 Ron, I think you are right as to the photocell being a better choice. I've already ordered a few to play with. You are also right in the devil being in the details of the code! I had a devil of a time trying to get the code to do what I wanted it to. Much of my flailing was caused by my lack of understanding of Hall switches and interrupts, but it still would have been tricky had I known how they work from the beginning.
ron bentley reacted
2022-12-16 7:34 pm
I'm planning on using a belt. This mechanism will need to travel around three feet, possibly a little more. I figure a lead screw that long could be hard to find.
A belt is probably the best choice. Another problem with a leadscrew is that they're hard to get absolutely straight and square out of the mount, so they can wobble quite noticeably.
You may find some noticeable "give" in a belt that long and it may stretch a bit over time, so make sure that you build in a generous belt tightening system.
Anything seems possible when you don't know what you're talking about.
2022-12-16 7:35 pm
OK, thanks.
Anything seems possible when you don't know what you're talking about.
2022-12-16 7:37 pm
@pritchs Same for a reed switch, but technically as @will mentions you have to de-bounce both and if an ISR is involved that is a bit of tricky code. A simple limit switch can either cut power, or signal a stop command (might need to debounce it too but no need for an ISR) Worried 1 switch can fail, put one on each side and wire in series. I used to work with steel mills and elevators that share a lot of similar controls as the slider. Never used a hall, used lot's of limit switches some many lbs in weight and some photocells.
First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.
Topic starter
2022-12-16 7:38 pm
@ronbentley1 Ron, in this case that's exactly what I wanted to happen in order to stop the stepper. The pin gets reset when the magnet is removed so that also fits with what I need.
ron bentley reacted
2022-12-16 7:39 pm
Ron Bentley
Creativity is an input to innovation and change is the output from innovation. Braden Kelley
A computer is a machine for constructing mappings from input to output. Michael Kirby
Through great input you get great output. RZA
Gauss is great but Euler rocks!!
2022-12-16 7:41 pm
@pritchs Sorry I need to ask some qualifying questions in order to know how to respond. How many years have you been a photographer, what gear are you using, how many decades of full time programming (40hrsx50wks) have you been doing, how many languages, how many OS's and applications?
First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.
2022-12-16 7:46 pm
Why do you assume that you can ignore bounce, or do you handle that in code ?
On further consideration, since this is more or less an emergency alarm situation, de-bouncing is probably not desirable and you'll want to react immediately.
Anything seems possible when you don't know what you're talking about.