Arduinos and Microcontrollers ref: Rotary Table Mew 249

[John HaineParticipant @johnhaine32865]

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.

[GreensandsParticipant @greensands]

Journeyman – I have sent you a PM

[JourneymanParticipant @journeyman]

Greensands, replied to PM. This image might help.

John

[Tony Pratt 1Participant @tonypratt1]

Posted by SillyOldDuffer on 09/12/2016 20:07:18:

Posted by Engine Builder on 09/12/2016 19:39:26:

sillyoldduffer,

I manged to alter the sketch to verify the key voltages and got similar results to your one.

If it helps other builders my LCD shield is badged DF ROBOT (Drive the Future)

This is the results I got.

• NO_KEY 1023
• RIGHT_KEY 0
• UP_KEY 98
• DOWN_KEY 253
• LEFT_KEY 408
• SELECT_KEY 639

Good work, you're officially a computer hacker now!

My LCD is a DF Robot as well – perhaps they all produce voltages like that.

I haven't got any further than getting the arduino and display to work. I wrongly thought I had a suitable motor, lack of which has taken the wind out of my sales…

Cheers,

Dave

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

[SillyOldDufferModerator @sillyoldduffer]

Posted by Tony Pratt 1 on 29/11/2021 19:43:05:

Posted by SillyOldDuffer on 09/12/2016 20:07:18:

Posted by Engine Builder on 09/12/2016 19:39:26:

sillyoldduffer,

I manged to alter the sketch to verify the key voltages and got similar results to your one.

If it helps other builders my LCD shield is badged DF ROBOT (Drive the Future)

This is the results I got.

• NO_KEY 1023
• RIGHT_KEY 0
• UP_KEY 98
• DOWN_KEY 253
• LEFT_KEY 408
• SELECT_KEY 639

Good work, you're officially a computer hacker now!

My LCD is a DF Robot as well – perhaps they all produce voltages like that.

I haven't got any further than getting the arduino and display to work. I wrongly thought I had a suitable motor, lack of which has taken the wind out of my sales…

Cheers,

Dave

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

[Tony Pratt 1Participant @tonypratt1]

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

[An OtherParticipant @another21905]

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.

[An OtherParticipant @another21905]

Duplicate post removed.

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

[An OtherParticipant @another21905]

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&quot;
lcd.setCursor(0,1);
lcd.print("Press Key:&quot;
}

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 &quot;
}
else if (x < 200) {
lcd.print ("Up &quot;
}
else if (x < 400){
lcd.print ("Down &quot;
}
else if (x < 600){
lcd.print ("Left &quot;
}
else if (x < 800){
lcd.print ("Select&quot;
}
} /End

[Michael GilliganParticipant @michaelgilligan61133]

Don’t you just hate those smileys

MichaelG.

[An OtherParticipant @another21905]

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

[Tony Pratt 1Participant @tonypratt1]

Thanks guys, comments noted.

Tony

[Peter Cook 6Participant @petercook6]

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.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Peter Cook 6 on 30/11/2021 12:38:27:

While this thread is resurrected, I thought I might point people at the prototyping sheilds I found when making my lathe controller. […]

.

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

[Peter Cook 6Participant @petercook6]

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

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Peter Cook 6 on 30/11/2021 14:17:11:

[…]

– although it would be interesting to know if they have permission from Vero for the name!!

.

Thanks, Peter … Yes that was my point

They do look very useful though

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Tony Pratt 1 on 29/11/2021 21:34:52:

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

Yes, you might have a duff Uno or Shield. Values higher than 1023 suggest a hardware failure. My LCD Shield came from DF-Robot, and I've used Sunfounder several times without bother, but the breed do turn up poorly sometimes. I try to avoid the very cheap no-brand boards, but the few I've used have been OK (I think I've only had two failures in over 100 purchases.)

You might try this test program, which can be used to test the Uno because it doesn't need the LCD shield plugged in. Instead it reports to the IDE's Serial Monitor at 9600baud.

Compile and load it onto the bare Uno, then turn the serial monitor on and set the baud rate to 9600 baud.

With nothing plugged into pin A0 should display a random value between 0 and 1023 due to picking up mains hum. Connect a jumper wire from A0 to the 3.3V socket:

Mine read 647 which equates to 3.16V (Maths: v= 647/1023 * 5V)

Reconnecting the jumper from A0 to a Gnd socket should read 0

And connecting the jumper from A0 to the 5V socket should read 1023

DO NOT connect the jumper from A0 to Vin!!! It will probably fry the ADC function,

This proves the UNO is Ok.

Next plug the shield in. The display won't work, but pressing the buttons down for a few seconds should show the ADC level each causes.

Fingers crossed, both work.

I can't think of a reason why A0 should ever read more than 1023. Possibly the ADC circuit behind A0 is has been spiked. They're robust unless fed more than whatever is on the supply rail, which is 5.0V. I've never killed one, but static might do it.

Dave

[John OlsenParticipant @johnolsen79199]

I've just been playing with an Arduino myself lately so found some of the above quite interesting.

A few points about speed and stepper motors. They can go quite fast, but sometimes need a few tricks. One is that in order to build up the current and hence the magnetic field quite quickly, the drive voltage can be increased. To avoid overcooking things when the motor is running slow or holding, this is done with either a constant current drive or more simply, a resistor in series. The high initial supply voltage gives a faster rise to the current, but the constant current part ensures that the current never exceeds what the winding is rated for.

Then there is the acceleration thing. Depending on the rotational inertia of the whole drive train, if you just start switching at a high speed, the rotor can lose lock. So the controller needs to be set up to accelerate at a reasonable rate, and similarly to decelerate at a reasonable rate. This requires that the controller knows in advance when it is going to be asked to stop the load, so is not so good for unplanned emergency stops. Really if high speeds and sudden changes are needed, a servo motor become a better solution.

I've just implemented some code from the web to allow using the Arduino to remotely display the output from the usual common digital calipers. The original code only did millimeters, so I have messed around a bit and after a few changes have got it to read out correctly for either millimeters or inches, including reading the fourth decimal place correctly. I might get around to doing a DRO for the Myford yet…

John

[Author]

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