Well, whatever is happening, I’m getting zero RPMS from the sensor calcs. The pwm value seems proportional to the value I call for, although I can get a really high value out (like 700) depending on what I call for.
I moved the cap, and now the router winds up slowly for a low speed but keeps going until it just stops, and when that happens, the rpms go from 0 to half a million, or 300000 or some stupid number. Clearly not a reading, so something is borked.
I found an extra sensor, so I tried wiring it up on the board and bypassing the one on the router just to see if I could get any response at all on the serial monitor, and I started getting some smoke from around the nano, so I yanked all the wires out and called it a night.
New nano, V1 board, (thanks Jessie) same problems. 0rpms back, pwm varies (8,12,176), full speed. I added a piece of tape to the router on top of the white paint, no help. I have no idea how to test anything on the dimmer except ac volts in/out and the triac resistance between legs. I’m not gonna buy another dimmer unless I can be reasonably sure that’s the problem.
It works for other people, so I must have done something wrong, but I’ll be damned if I can figure out what.
I guess I’ll just throw it in a box until somebody smarter than me has the time/inclination to do a proper writeup, because I’ve got things to do and this is taking up too much time and effort.
Thanks for the help up to here.
As for the RPM readings. If you do have everything wired right, you may be having the same issue I had with the signal from the photo sensor. The sensor sends a voltage back to the Arduino that is proportional to the amount of reflected light it is seeing.
Here’s what you need to do to test this…
- Hook everything up like normal except for the signal wire coming back to the Arduino. Instead, connect this wire to the postive lead of your multimeter (set to DC).
- Connect the negative lead of your multimeter to the ground that is shared by your arduino and sensor.
- Manually spin the router slowly and watch the voltages. You should get a high voltage and a low. Record these.
The arduino must see a voltage higher and 3V to read a HIGH state. It also must see a voltage lower than 1.5V to read a low state.
If this is not what your readings are showing, then you need to play around with the resistor that is feeding the photo sensor… or do a better job than I did with the dark and light surface the photo diode is seeing on the router.
1 Like
I’ll give that a shot.
1 Like
The high is pretty good, 4.8-4.9v. The low dips to 1.2-1.3.
Seems ok, right? Also indicates that I have the wires to the board correctly. But still no rpms being calculated. It is what it is.
I might try to rig the sketch to send a really low pwm_out, like 0.3v or something. See if that fits anything for me. Even if it does manage to spin slowly, I’ll never be able to use this without being able to read rpms. And if I’m getting the right voltage and no calculated rpms, something is really wrong.
I don’t know whether you’re certain where in the system you’re having issues, but you can also rig a potentiometer to feed the PWM value as a way to test whether the dimmer board is reacting properly to that input. I actually permanently added a dpdt switch to the PWM input on the dimmer board which allows me to switch between “manual” control via the pot and having the nano do CNC control.
1 Like
Based on that I would think you have a good black/white contrast for the photodiode and its wired correctly. The 1.2-1.3 should be okay… but it might be too close? If I remember I played with the 10K resistor… changed the value of it. That will raise/lower the “Range” of the voltages. So you might get it to read 1.0-4.5 instead, for example and give yourself some room for error.
In my situation I think I was getting like 0.5 to 2.9 (as I probably did a poor job with painting the spindle) and changed the resistor to raise it.
Edit: The more I think about it may have been the other resistor. Basically changed the brightness of the LED in the sensor.
1 Like
I have absolutely no clue what’s going on. That sounds like a good way to test the dimmer, and I think I have some pots somewhere. The pwm out from the nano goes to over 4v almost immediately and I can’t figure out why I get 0 RPMS.
Definitely time to set it aside, though. I have a whole pile of stuff I need to make.
“Focused surrender.” Work on it until you get stuck, put it away, and the answer will come to you when you least expect it.
2 Likes
It occurred to me that the pwm out was sending 4 volts, so maybe I could use the pwm signal from the uno. I got nuthin. I double checked that I was getting voltage from the pwm (0.4v) and by the time I got back to the dimmer, the 60hz lights wouldn’t come on. Even not plugged in, they don’t flash like they used to. Even worse, the uno doesn’t like being plugged into it. All those Leds dim and cncjs keeps resetting.
Whatever the original problem was, I definitely have a bad dimmer now.
Well, I bought a replacement dimmer last week, and I got to a point on my next project where I’m waiting on my 3d printer, so hey, bust it back out, right? Wired up a pot to the dimmer, and it works just fine. Makes me wonder if I wouldn’t be better off going back to the dumb router controller (I’m going to be shrinking my primo soon and putting it on light duty, so it might not be so bad).
But first, I painted over most of the white so it’s just a pie slice now, and I painted my sensor housing black (it’s white pla). I might also try some clear tape over the sensor for some troubleshooting.
Update: I get values from 0.6V-4.8V…but only when I wiggle the connectors on the circuit board. I just have done a crap job there. I discovered it when I tried to probe for voltage on the led. I’ll update when I fix that.
ok, well, i seem to have a broken trace at pin 4 on the sensor connector so I jumped a wire to the two pins where it goes. Really nasty looking, but apparently functional. Remind me to tell you about some of the emergency plumbing repairs I made back at the buffet, lol.
Anywho, despite getting what seems to be really good readings from the signal wire, it still doesn’t work. Turns out that when I plug it in to the board, I ONLY get about 0.8V at that wire. I tried another pin, and I only get about 4.5 volts. Does that even make sense?
I’d like to help, but I have no idea what you are talking about. Maybe a picture would help?
That plug comes from the sensor in the dewalt. I’m PRETTY sure I got the order correct per the note in the pid thread. The red wire is the signal from the sensor. When I measure the voltage drop from it to ground, I get something in the range of 0.6 to 4.8, depending on the rotation (by hand) of the tool.
As soon as I plug it in to the board, though, it goes to 0.8, no variation despite rotating the tool.
Curious whether I’d broken something else in the board, i assigned a different (unused) pin to the photo sensor in the sketch, plugged into that, and it went up to 4.8 (probably a feature of how arduino works?). I think this last step wasn’t very helpful at all, and I’m still not sure what I was expecting to learn.
I think you know this, but just to be clear, the 4.8 or 0.6 depends on the angle of rotation, not speed.
It may be that the input has the internal pullup in your second test?
Right, thanks. I’m expecting (based on some help above) that switch below 1.5V and above 3V tells the arduino that the angle has changed, and the sketch does some math based on this to calculate the RPM. Since my next immediate problem is that the nano is outputting 0RPM (with serial enabled), the pin dropping to a flat 0.8V and not changing seems like a reasonable culprit.
The sketch does define the pin with a pullup (excerpts below). I think pin2 is connected to the signal pin (primarily), a capacitor, a big resistor, and the ground. Maybe that resistor is dragging pin 2 from ~5V to 0.8? And since it wasn’t wired in when I tried the other pin, it stayed clsoer to 5V? Does it make sense to try this without the pullup? I only have a vague understanding of pullups, but I think the idea is to keep the voltage higher than 0?
//in declarations
const int PHOTO_PIN = 2;
//in setup
pinMode(PHOTO_PIN, INPUT_PULLUP); // Spindle RPM input pin
All the voltages having to do with the photo sensor are 5V so I doubt you have fried anything. But the fact that it drops to 0.8 makes me think your pin on the arduino is shorted to ground? Power the arduino and check resistance between the pin and ground pin with meter.
The way I read the schematic, that pin GOES to ground on purpose through the big resistor, no?
I also have a brand new board, and I just checked it from the sensor signal mounting hole to one end of the resistor mount, and from the other end to ground. That definitely happens, and I haven’t done anything to break that one yet. Have I read the thing wrong and the signal wire isn’t supposed to go there? I can power up the one I’m using after work.
With Pin 2 configured as an input and the board powered up it should have a high resistance to ground, or else out comes the smoke. Someone correct me if I’m wrong.
The 10k resistor acts as a pulldown to ground to avoid a “floating voltage” on the wire connected to Pin 2. For the 4.8v to disappear when you connect it to the arduino, it almost has to have a low resistance path to ground. Figure out where that path is. Could be the arduino pin. Could be a bad trace in the breakout board. Triple check all of your connections.
And make sure you have a shared ground across all of your components!
Looks like I have 9.6k powered, unpowered, from pin 2 to ground whether I pick it up on the arduino or from the plug for the sensor wire.
Also triple checked the sensor starting at the dot with 1, clockwise thriving the other 3 so that the darker piece (sensor of I understand correctly) has 1/2 and the clear piece (led) has 3/4. That goes left to right on the board 2431. 2 goes to the resistor, one leg of the cap, then d2. The other leg of the resistor and cap go to ground. 4 goes to ground. 3 goes to power through a smaller resistor. 1 goes straight to power.
I think I understand what you mean about a lower resistance dropping the voltage, but I can’t find it.