Arduinos and Microcontrollers ref: Rotary Table Mew 249

Ha! It seems : followed by S codes for that smiley!

Neil

Dave, how about using the serial interface from the main programming pc which presumably is still available. Though many won't have the pc in the workshop I guess some do for other CNC & 3D printing.

Loads of Arduino (and other) stuff at DFRobot - delivery is quick and prices not bad.

And CPC Farnell has a Maker brochure. I wish this stuff had been around when I was younger!

Murray

It's not about the £1.50, it's about building a better mouse trap.

Indexers for most people are use occasionally devices and just have a couple of buttons and nested menu's and loads of clicks isn't something that stays locked in your mind.

From replies since I have posted it appears that I'm not the only one that thinks that way. All the hard work is done. The sketches are out there, it just needs someone to demonstrate that it is truly a modular system.

Been done.

Got the tee shirt.

Looking back thru some files and pictures dated around November 2010 I found a system that I paid to have developed for British Nuclear Fuels, can't say what the job was or they would kill me but it did involve a £80,000 camera [ no typo ] and it had to work as it was in the hot side, and still is.

This is the simplified screen we used for testing.

Their system was far more complex and had a load of features we would never use and was integral to their software. This was very simple and worked well.

It took signals from the PC, via a USB lead to an Arduino UNO and in turn this spat out step and direction to a Leadshine stepper driver.

It only needs the USB in and 3 wires out Step +, Dir + and step and dir -

The extra wires were for limits, remote start and stop etc.

Because I paid for this I still own the files and the rights to use it.

I have to say that looks very good indeed.

It should do for what it cost

Seriously this was the test software which was just a spin off from BNF's job.

Drawback to this is you are tied to a PC which is why I have never pushed it. It was more a reply to Bazyle asking about PC's.

I taught myself to program back in the early 80s, have always been interested in the lowest level operation of computers, and always worked as a programmer.

And yet not one of my 4 children has shown the slightest inclination to look beyond watching youtube or playing games.

I think their saturation in computers has the opposite effect - to me as a teenager they were new and interesting and thought-provoking. To today's kids they're like a washing machine, VCR, or DVR. There is no real wonder to it.

There will always be people interested in them but I don't think we're ever going to raise a generation who consider coding a normal skill any more than we ever had a generation who could all do plumbing, or design rockets.

I kind of disagree with the user-friendly part too. Writing programs on a BBC micro or Commodore 64 was a lot easier than all the hoops you have to jump through today, whether it be installing an IDE, running a python interpreter or whatever.

There is more info about though, and its a lot easier to get it.

Here is a link to some Chinese membrane keypads on The Bay, 2 for £0.99 and free shipping.

These, and the press button ones, are simply a 4x4 matrix connected via 8 wires (4 across, 4 down).

If you want a library for simple integration, there is one on the Arduino Playground, or you can write your own code to do the same thing (can make for smaller code, as you do not need to cater for different sized keypads).

I must admit I had been thinking along slightly different lines, the rotary being used to do the up/down, but also when in jog mode to actually do the movement. In run mode I had considered using a single axis joystick, but then wondered if a rotary, joystick and something to change mode was to many controls. As with so many things what can make a good application bad is the user interface.

Baldric

Thanks for the links but those keypads have a 7 pin socket, not 8. I was hoping to just have a plug and play keypad as I have no understanding of programming a sketch for Arduino. I see a 7 pin socket on the UNO and a further set of 9 upward facing pins adjacent to the socket, would the keypad connect to either of these ?

Thanks, Emgee

Just re-checked the picture on the Ebay listing I linked to - it definitely has an 8 pin connector.

Most of the items marked as suitable for use with an Arduino are not plug and play, they are merely something mounted on a PCB, maybe with some extra electronics and a pin header to interface with it. The assumption is that someone is going to write a sketch to make use of it, or combine a number of libraries in a sketch if they don't feel like writing it all from scratch.

I am sure you are aware that the Arduino is merely a microcontroller on a board with no intelligence other than what you upload via a compiled sketch to it - it is in effect a blank canvas.

If you want to have, for example, an LED light up, it makes no difference to the Arduino if it is attached to pin 1, or pin 5, that is your choice, just so long as you tell it, in your scetch, which pin to send the voltage out of in order to light the LED.

The one in your link is a 4x3 matrix so 7 pin socket

Similar 4x4 pads do have 8 pins such as this

Hi Baldric,

Not much progress as I've been diverted on to parent sitting; my mum is just out of hospital.

I hadn't thought of using the switches as you describe, but it is logical! Just goes to show why interfaces are difficult to design. We all expect things to work our way. I was going to jog by pressing the joystick, but the rotary encoder has a press switch too.

At the moment I'm tendiing towards a matrix keypad with the option to control it with a serial interface as suggested by Bazyle as well. It wouldn't be difficult to do away with the physical USB connection with a Bluetooth wifi module and put a graphical interface on a tablet.

A big advantage of a keypad is that mode-select can be done with a single keypress.

My first step has been to check there are enough spare pins on the Arduino. 8, 9, 4, 5, 6, 7 and 10 are used by the DF Robot; 2, 3, 11, A0, A1 and A2 are used to control the motor and for temperature sensing; 0 and 1 are the serial interface. This leaves 5 spare pins (12, 13, A3, A4 and A5) when 7 are needed for a 4x4 keypad.

An Arduino Mega has plenty of spare pins but gosh, they're about £10! So I think I'll dump the temperature sensors and repurpose A1 and A2.

Next step is to separate the motor drive code from the existing key button functions; at the moment they are interleaved. Then I can apply different control interfaces to work the motor. As an armchair project, it's going rather well. There will be tears when I start coding and reality bites me!

Dave

Although I'm not building a motorised rotary table, I'm experimenting with stepper motors and Arduinos at the moment. So I did read this thread with much interest. I have to admit I was a bit shocked when I checked the links given by J.Swift on the 7/2. One TB6560 driver for £ 11.99! Without knowing this thread (and because I fried the driver I used before) I ordered a couple of drivers via Ebay, and among them I got two such drivers for $ 9.90, postage free.

And now, Mr. Costa: the Chinese are not stupid, and they know about VAT taxes etc. in Europe. On that famous customs slip they stated (in that case) "Electronic parts, value $ 3.00" . Not that it would make a difference, as in my country values below around £ 50.00 are not taxed - the expenses would cost more than the tax. I really don't think that anywhere in Europe imports in one-digit values are taxed - if I'm wrong, how many cents/pennies then?

So, don't be afraid of ordering in China - but naturally it won't be in your letterbox tomorrow.

Regards, Frank

My mistake - I meant to link to this one here, same price of £0.99 for 2 but 4x4 matrix.

For anyone interested the latest update to my keypad based indexer and a pdf to read are at this Dropbox Link

Using a cheap matrix key pad like this:

It provides the same functions as the Gary Liming's program, but has been extended in various ways. (Mainly the ability to type in numbers, PAUSE, REWIND and control via the USB port.)

• 'A' sets Angle mode. The angle may be a decimal. eg. 41.75°
• 'B' sets Bump mode (aka Jog)
• 'C' sets mode to continuous (ie motor turns until stopped)
• 'D' sets DivStep mode.
• '*' starts and stops the motor, abandoning the current operation. (The next operation will continue from the stop position, see '1' and '5' for palliatives.)
• '0' toggles motor direction between clockwise and anticlockwise
• '1' rewinds the motor to the start point of the previous operation. Up to 10 previous operations may be rewound.
• '5' pauses or restarts the current operation, which then completes as normal.
• '9' enters ratio mode. The ratio may set to any integer value.
• '#' allows control numbers to be entered, for example to set a required angle, or the bump distance. Numeric entry is ended by typing a second #. In number mode '*' doubles as the decimal point.

The display uses the DFRobot, though it's push buttons are ignored. It is not difficult to substitute a cheaper 1602 display only board or an I2C display. In this example, Bump is selected with 10 steps clockwise. Pressing '*' jogs the motor. A Bump too far may be undone by pressing '1' to REWIND it, which is handy.

When the motor is running a progress countdown is displayed.

If you try this please report any bugs. Although there's been lots of testing it's amazing how the bleeding obvious still slips through!

The pdf includes more examples and the wiring diagram.

Dave

I've built a driver for my turntable exactly as specified in the article and cross checked with Gary Limings articles. My problem is that when I power it on it works as advertised to the point where it displays the correct startup screen I.E

Select Mode, Mode = Step. If I press Select nothing happens. Pressing Left scrolls through the Modes. Pressing Up also scrolls through the modes and Down Scrolls through the modes in the reverse direction. Pressing the "Right" button does nothing. Pressing reset does a reset and also switches off the run light on the stepper driver module. At all times whilst power is applied the actual stepper motor is locked. I have tried another display module and also a different processor module. ( an Arduino Mega) I have also tried it with no stepper driver connected. all I get is the above. Does any one have a clue what I'm doing wrong? I have been very careful in my wiring and anyway I have tried it with just the Arduino Uno and display shield.

Hi Centurion,

This sounds like a well known problem that was discussed earlier on this thread. See my post on Page 4 and John Swift on page 8.

Those buttons are not individual switches. Instead, they cause a voltage change when pressed. The Arduino measures the voltage and decides which button has been pushed. Your problem is probably down to a small difference between the various versions of the Display Board. (Apart from there being a Mk1 and a Mk2, there are plenty of clones.) To fix it all you have to do is alter a few numbers in the Arduino Sketch to match your particular display board.

The code is the six 'if (Key_in ... )' statements right at the end of Gary's sketch. It looks like this:

int read_LCD_button() // routine to read the LCD's buttons
{
int key_in;
delay(ADSettleTime); // wait to settle
key_in = analogRead(0); // read ADC once
delay(ADSettleTime); // wait to settle
// average values for my board were: 0, 144, 324, 505, 742
// add approx 100 to those values to set range

if (key_in > 850) return NO_KEY;
if (key_in < 70) return RIGHT_KEY;
if (key_in < 250) return UP_KEY;
if (key_in < 450) return DOWN_KEY;
if (key_in < 650) return LEFT_KEY;
if (key_in < 850) return SELECT_KEY;

}

Note Gary Liming's comment

// average values for my board were: 0, 144, 324, 505, 742
// add approx 100 to those values to set range

In the example above are the key_in values I used. (850, 70, 250, 450, 650, 850) You might try those values first.

If that fails, download this sketch and temporarily install it instead of Gary's program. All the sketch does is display the actual number generated by your keys. Write them down, then change the key_in values in Gary's sketch as per his +100 comment and re-install it.

With luck all should now be well.

Dave

Thanks I followed your advice and download the "test" sketch and using the numbers obtained modyfied the 2.3 sketch. All now works according to Hoyle. Many thanks for your response. I thought I'd checked all the relevent threads, but you know what they say about thought.