I want to build the Hall Effect Sensor as in the link below. I would like to use the Logic Chip approach as mentioned in the article. What I’m not understanding is the portion of the circuit in the lower left of the schematic. It appears to sit on it’s own. Can someone explain what is going on there.
If anyone has another approach for DIY Hall Effect Sensor that you can share please do. I am a newbie trying to learn electronics. I would like the sensor to have a green led to stay on during normal operation. The green light would go off and the red led would come on to indicate the switch was triggered.
The section in the bottom left shows +5v connected to a capacitor and from the capacitor to ground. Sometimes in schematics parts of the circuit are broken out so as to keep the schematic itself clean. The section that is broken out will label all the connections as to where it goes in the larger circuit. In this case, the cap is there just to keep the voltage smooth.
I’d like to build my own to learn. Also, there is no shipping option to CANADA. The currency conversion and shipping alone is also a deterrent. But at the end of the day it looks like it’s a solid product he has but I really would like to learn.
The circuit, it’s fairly simple, it designed to operate just like a mechanical switch for compatibility across various controllers. You would configure your controller limit settings for Normally Open (NO). The sensor wire goes to the corresponding Limit Port and GND and with 5V or 3.3V. When it approaches a magnetic field the voltage is brought low at the sensor port (just like a mechanical switch). Basically its a short to ground.
If you reach out to me via email michael@omiccioli.com I can see what it takes to ship to Canada if your interested. I have been shipping to England, Switzerland and Spain and the charges have been reasonable.
Micheal, thanks so much for sharing this. I’m new to electronics but I’m learning. Would you mind explaining the actual values of the capacitor and resistors. I don’t want to mess those up and interpret the values wrong.
While input filtering is nice, the actual proper position of a filter capacitor is as close to the logic IC VCC and ground as possible. I just figured I’d add that today. I usually put a filter both places on circuits myself. Where power enters boards, and where devices may need them. Although on a small board like this one, one close to the chip is all you need.
@Rob_Mitchell1 if you’re really interested in electronics then buy yourself a set of eyes. Which with electronics is an oscilloscope. Because without one you’re groping around blindly. Not to say that the blind can’t get around, but vision makes things a lot easier. Electronics is the art of signal conditioning. So it helps to see what shape signals are actually in.
Paul I agree, the other consideration is travel speed. CNC routers, 3D printers and Lasers are not so fast that trips happen more than once per second.
@Paul_Frederick I appreciate the suggestion of getting an oscilloscope. I am interested in getting one but price and intimidation of it being complex has held me back. I will reconsider in light of my recent work on these switches.
@Rob_Mitchell1
You do not have to start out with the greatest scope made. I know I didn’t. In fact most cheap instruments should serve your needs well.
I know scopes have a lot of intimidating switches, and knobs on them. But once you use one the principal of operation is simple enough that you should be able to make quick sense of it all. In a way it is like tuning a radio. You dial in on the frequency of interest.
A scope is basically divided into two parts. There’s time, and amplitude. Time travels along the X axis, and amplitude is on the Y. All those switches and knobs do is allow the user to adjust the parameters of what is being measured. So you have your time base, and your sensitivity controls.
A scope is like an instrument that gives you electronic superpowers. Who doesn’t want a superpower? Electron vision.
@Michael_Omiccioli
You have to be careful with cheap DSOs. They don’t always show what is really going on due to how they work. To increase bandwidth low sample rate units extrapolate waveforms from aggregate data. They essentially stitch pictures of waveforms together from time slices of a number of samples. This behavior can mask transients, which may be precisely what one is looking for in a signal.
I don’t have a tool to demonstrate the difference in precision. However, I established an offset from the homed position. Then cut an SMD PCB board. Then ran the routine a second time after re-homing. I did this with both Mechanical and Magnetic limit switches. While the mechanical was very close the magnetic was spot on and I was hard pressed to identify variations. Not super scientific, one of my YouTube videos shows an even simpler test.
@Michael_Omiccioli Hi Michael, I’ve been using http://easyeda.com to mock up the limit switch, it’s a great tool for someone like myself. I’m trying to find the same connector you used for quick connect wires. Would you mind sharing the part number. I’m hoping to run this through my OX CNC today and etch my first circuit.
Rob the part is from Phoenix Contacts. I’m not at home right now so I can’t look up the actual part number. You should be able to find it on digi-key or Mouser.
