Arduinos and Microcontrollers ref: Rotary Table Mew 249

Yes of course! I didn't think it through.

With micro-stepping selected the controller output looks like a synthesised sine wave on my oscilloscope. It's made of spikes. I've no idea what happens to the waveform when it hits the motor coils but there must be limits to what the inductors will work with. Another 'find out how that works' addition to my 'to-do' list.

Ta,

Dave

This is a chopped drive - the motor inductance smooths it out to approximately sinusoidal current.

I have just acquired a copy of MEW 249 to read up about the Arduino controlled indexer but am having problems in seeing exactly how the Uno Board is spaced off and attached to the lid of the enclosure. Could some kind soul please elucidate.

Four holes in the Uno board, 4 matching holes in the display and 4 holes in the case clear plastic between display and case also with four holes. Bolt through everything could put plastic tube spacers in but not really required if nuts are lightly tightened down.

Have a look at my version on ** Journeyman's Workshop ** click on the images to enlarge.

John

If you have some small nut driver sockets a simple tip to make spacers is to mount one in the lathe chuck, feed a small stack of appropriate sizes nuts into the hex hole, bring a nominal clearance drill for the thread size in the t/s so so it nearly touches the first nut, start the lathe and feed slowly. As each nut is drilled out it slides onto the drill as you go into the next. Use nylon nuts for plastic spacers.

Journeyman - I have sent you a PM

Greensands, replied to PM. This image might help.

John

Hi All, I'm now having a go at this project but have failed at the first hurdle, my figures are NO KEY 1022, SELECT 6412, LEFT 4112, RIGHT 0022, UP 1002, DOWN 2572, these seem way too high?? any ideas? Thanks, Tony

That's strange Tony. The buttons short out a line of resistors (circuit here, see lower right), and the values can only be between 0 and 1024. Your 1022 and 0022 look right but the other readings are off the scale. What hardware are you using?

Dave

Hi Dave, thanks for the swift reply! The board is a Sunfounder model Uno R3, the shield has no name that I can see? I have ordered a new board & shield from Amazon to see if the figures make any sense with them, if no go is there any particular brand that is reliable, as most seem to be made in China generics?

Thanks Tony

Arduino Unos have an analog input resolution og 10 bits, so the value read will be between 0 to 1023. Some Arduino board types have 12 bit resolution, so the value read will be between 0 and 4095. It is possible there are some 3rd party boards with 12 bit resolution (I have at least 2 of these)

As noted, the shield has a resistor chain connected between 0 and +5v, and the pushbuttons are connected across these resistors,so when you press one, the value of the chain changes, therefore the voltage at the Arduino analog input is changed, and the Arduino reads this as a value between 0 and 1023 (see above) - note that this switching is on the shield, not the Arduino.

The values read are not 'absolute' - they can vary slightly, and will not be the same from one board to another, due to things like resistor tolerance, so when testing for a value, you should check they lie between an upper and lower value (say a range of +/- 5 or 10).

It would appear to me that the odd values noted by Tony may be due to a programming error. There are many shields carrying LCDs/buttons - they all have different resistor chains, so although a 'testing' program could have the same format, the values read will be different.

Duplicate post removed.

Edited By An Other on 30/11/2021 10:20:37

If its any use- below is my test code for these LCD/Button Shields.

.

#include <LiquidCrystal.h>

//LCD pin to Arduino
const int pin_RS = 8;
const int pin_EN = 9;
const int pin_d4 = 4;
const int pin_d5 = 5;
const int pin_d6 = 6;
const int pin_d7 = 7;

const int pin_BL = 10;

LiquidCrystal lcd( pin_RS, pin_EN, pin_d4, pin_d5, pin_d6, pin_d7);

void setup() {

lcd.begin(16, 2);

lcd.setCursor(0,0);

lcd.print("LCD Key Shield";
lcd.setCursor(0,1);
lcd.print("Press Key:";
}

void loop() {
int x;
x = analogRead (0);
lcd.setCursor(10,1);

//The values given below may need changing depending on the LCD/Button shield
if (x < 60) {
lcd.print ("Right ";
}
else if (x < 200) {
lcd.print ("Up ";
}
else if (x < 400){
lcd.print ("Down ";
}
else if (x < 600){
lcd.print ("Left ";
}
else if (x < 800){
lcd.print ("Select";
}
} /End

Don’t you just hate those smileys

MichaelG.

Thats really annoying - they weren't there when I posted. I left the site, came back later to check something else, and found this - worse than graffiti. If anyone is confused,it seems that the smileys replace the right-hand round bracket - they aren't part of the code - and that smiley was deliberate!

Something else odd - when I opened the thread, the line at the top indicated there were 12 pages (7 89 10 11 12), but after posting, this changed to 10 pages (7 8 9 10) - are there some pages missing?, or is it just this lousy software.

Edited By An Other on 30/11/2021 11:08:42

Thanks guys, comments noted.

Tony

While this thread is resurrected, I thought I might point people at the prototyping sheilds I found when making my lathe controller. They are from Electronics - W19 Design, and have by far the nicest layout I have come across.

Rather than being an array of through holes, there is an array of 3 or 4 hole tracks and some longer ( power rails) which makes making connections between components and the Arduino pins far simpler and neater.

I have no connection other than a very happy user.

.

Those do look very tidy, Peter

But, am I right in assuming that the company has no association with Vero

[ purveyors of strip-boards to the gentry ] ?

MichaelG.

.

Ref. http://verotl.com/circuitboards/protoboards

Edited By Michael Gilligan on 30/11/2021 12:58:30

Michael, Not that I know of - I'm just a customer. They seem to be a firm that makes custom exhibition stands, and this is something they designed to make construction of Arduino based specials easier.

Personally I'm glad they put them on the market - the short tracks make laying out and building one-off's far easier than the usual shields - although it would be interesting to know if they have permission from Vero for the name!!

Edited By Peter Cook 6 on 30/11/2021 14:19:38

.

Thanks, Peter … Yes that was my point

They do look very useful though

MichaelG.