Arduinos and Microcontrollers ref: Rotary Table Mew 249

[SillyOldDufferModerator @sillyoldduffer]

Hi Emgee,

I've been playing too and have a similar problem. I'm pretty sure the issue is the bit of code that works out which key is being pressed. It's the very last function at the end of the Sketch and 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;

}

The way the code works is that pressing a key generates a voltage that's measured by the arduino. The voltages can vary between individual LCD boards. Mine generates voltages that don't quite line up with the values in the sketch. I get:.

• NO_KEY 1023 (This is OK)
• RIGHT_KEY 0 (This is OK)
• UP_KEY 99 (This is OK)
• DOWN_KEY 255 (This is only just OK)
• LEFT_KEY 409 (This is WRONG – the sketch thinks the DOWN_KEY has been pressed)
• SELECT_KEY 638 (This is WRONG – the sketch thinks the LEFT_KEY has been pressed)

Easily fixed. I change these lines in the function to read:

if (key_in > 850) return NO_KEY;
if (key_in < 70) return RIGHT_KEY;
if (key_in < 230) return UP_KEY;
if (key_in < 350) return DOWN_KEY;
if (key_in < 450) return LEFT_KEY;
if (key_in < 850) return SELECT_KEY;

You can use the IDE's monitor to find out what voltages are stored in key_in when the various buttons are pressed. To do this, add the command

Serial.begin(9600);

to the function called setup at the beginning of the sketch.

Then add Serial.println( key_in ) to the read_LCD_button function as shown:

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

Serial.println( key_in ); // for debugging

if (key_in > 850) return NO_KEY;
if (key_in < 70) return RIGHT_KEY;
if (key_in < 230) return UP_KEY;
if (key_in < 350) return DOWN_KEY;
if (key_in < 450) return LEFT_KEY;
if (key_in < 850) return SELECT_KEY;

}

Verify and Upload the sketch, then turn on the monitor with Tools->Serial Monitor. It may be necessary to set it to 9600 Baud. (bottom right of screen)

The monitor should start spewing the number 1023. When you press a button a different number will appear in the stream. This is the value your LCD Board uses to signal that key is pressed. Record the value produced by each key and compare it with the values in the Sketch, changing the sketch as necessary.

After you've got it working it's tidy to remove the Serial commands. The Sketch will still work if you leave them in.

Hope that makes sense!

Dave

 

 

Edited By SillyOldDuffer on 09/12/2016 17:03:14

[JourneymanParticipant @journeyman]

Also playing with this, first time with Arduino. More by luck than judgement my key presses seem to work OK and the functions work as per the program. I was testing with the UNO and LCD shield just plugged into the USB port on my PC. I was wondering if the available output from the USB port was on the limit it might affect the key press analogue voltages as it is just a resistor divider chain and if the starting 5v is below spec could have strange consequences down the line. I hasten to add that I have no experience or knowledge in this area! Just trying to learn and keep the little grey cells moving…

John

[Engine BuilderParticipant @enginebuilder]

Sillyoldduffer, your not so silly!

I do not quite understand, as a Arduino virgin, where I should put the line Serial.begin(9600);

I see void setup() { in the sketch.

Anyway I just changed the key_in values to the same as your and it seems to work now.

Thanks for the help.

I would like to check what values my keys are giving though so could you clarify where to add that Serial.begin line please.

[Roger Williams 2Participant @rogerwilliams2]

My first time with the Arduino Uno too, and after getting something like " done uploading ",, I get bugger all on the LCD apart from the light !!. Oops. Any thoughts anyone please, bearing in mind I dont really know what Im doing.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Engine Builder on 09/12/2016 17:39:26:

Sillyoldduffer, your not so silly!

I do not quite understand, as a Arduino virgin, where I should put the line Serial.begin(9600);

I see void setup() { in the sketch.

Anyway I just changed the key_in values to the same as your and it seems to work now.

Thanks for the help.

I would like to check what values my keys are giving though so could you clarify where to add that Serial.begin line please.

Trust me : I am quite Silly, quite old and a bit of a duffer!

the Serial.begin can go anywhere inside setup(). This is where I put it:

void setup()
{
// Create some custom characters for the lcd display
byte c_CW[8] = {0b01101,0b10011,0b10111,0b10000,0b10000,0b10000,0b10001,0b01110}; //Clockwise
byte c_CCW[8] = {0b10110,0b11001,0b11101,0b00001,0b00001,0b00001,0b10001,0b01110}; // CounterClockWise
#ifdef Fahrenheit
byte c_DegreeF[8] = {0b01000,0b10100,0b01000,0b00111,0b00100,0b00110,0b00100,0b00100}; // degreeF
#endif
#ifdef Celsius
byte c_DegreeF[8] = {0b01000,0b10100,0b01011,0b00101,0b00100,0b00100,0b00101,0b00011}; // degreeC
#endif
lcd.createChar(1,c_CW);
lcd.createChar(2,c_CCW);
lcd.createChar(3,c_DegreeF);

Serial.begin(9600);
// begin program

Glad it's working!

Dave

[SillyOldDufferModerator @sillyoldduffer]

Posted by Roger Williams 2 on 09/12/2016 17:42:35:

My first time with the Arduino Uno too, and after getting something like " done uploading ",, I get bugger all on the LCD apart from the light !!. Oops. Any thoughts anyone please, bearing in mind I dont really know what Im doing.

This could be another easy one I hope. Top left on the LCD DIsplay is a Blue Box with a small brass screw on stop. This is the multi-turn potentiometer that controls contrast. Try turning it with a small screwdriver (could need to go either way). Be gentle and don't overdo it – I broke one once.

Dave

[JAParticipant @ja]

Posted by SillyOldDuffer on 09/12/2016 17:54:08:

Posted by Roger Williams 2 on 09/12/2016 17:42:35:

My first time with the Arduino Uno too, and after getting something like " done uploading ",, I get bugger all on the LCD apart from the light !!. Oops. Any thoughts anyone please, bearing in mind I dont really know what Im doing.

This could be another easy one I hope. Top left on the LCD DIsplay is a Blue Box with a small brass screw on stop. This is the multi-turn potentiometer that controls contrast. Try turning it with a small screwdriver (could need to go either way). Be gentle and don't overdo it – I broke one once.

Dave

The photograph was up-side-down in the article (just to show that I have had a good read of what is a thought provoking article).

JA

[Engine BuilderParticipant @enginebuilder]

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

[SillyOldDufferModerator @sillyoldduffer]

Posted by JA on 09/12/2016 19:33:28:

Posted by SillyOldDuffer on 09/12/2016 17:54:08:

Posted by Roger Williams 2 on 09/12/2016 17:42:35:

…

…

The photograph was up-side-down in the article…

JA

My punishment for specifically referring to 'top left' of the photo in the text! Glad you found the article thought provoking, rather than baffling (I hope).

Cheers,

Dave

[SillyOldDufferModerator @sillyoldduffer]

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

[Engine BuilderParticipant @enginebuilder]

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

Thanks for the help.

I'm on the next step now, ordered the driver!

[Roger Williams 2Participant @rogerwilliams2]

Silly Old Duffer, thanks for that about the potentiometer, I tried many turns both ways but still nothing. I might try uploading again to see what happens.

[JAParticipant @ja]

Posted by SillyOldDuffer on 09/12/2016 19:56:37:

Posted by JA on 09/12/2016 19:33:28:

Posted by SillyOldDuffer on 09/12/2016 17:54:08:

Posted by Roger Williams 2 on 09/12/2016 17:42:35:

…

 

…

 

The photograph was up-side-down in the article…

JA

My punishment for specifically referring to 'top left' of the photo in the text! Glad you found the article thought provoking, rather than baffling (I hope).

Cheers,

Dave

Certainly not baffling although I would not have started with a hot air engine.

Sorry. I think I have cross linked two threads again (that is this one is about the rotary table and I am referring to the hot air engine data logger).

JA

Edited By JA on 09/12/2016 23:23:54

[Carl Wilson 4Participant @carlwilson4]

Interesting stuff, just seen all this. I’d no idea that the different Lcd/key pad Shields outputted different voltages.

Regarding the too bright Lcd, exactly same thing happened to me. Just adjusted the contrast pot as Dave points out.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Roger Williams 2 on 09/12/2016 22:27:15:

Silly Old Duffer, thanks for that about the potentiometer, I tried many turns both ways but still nothing. I might try uploading again to see what happens.

Hi Roger,

Oh dear you might have a dud.

Uploading again is the right thing to do. Keep an eye on the console display at the bottom for error messages.

The other thing to check is that all the LCD plug pins are correctly located n the Arduino socket. I once managed to bend one behind…

Good luck,

Dave

[Roger Williams 2Participant @rogerwilliams2]

S O Duffer, thanks for your help, I will have another look at it tomorrow. Cheers.

[Engine BuilderParticipant @enginebuilder]

Just been looking for a suitable motor for this project. The one in the article is said to be 24 kg/cm torque but looking at the source metioned I cannot see one with that specification.

I am confused too about the voltage rating of these motors. I assume a 12v is needed as that is the supply voltage.

The one closest to the specified one has a rated voltage of 3v and the one used in the Liming article seems to be 8.6.

i am confused what to get!

[Neil WyattModerator @neilwyatt]

Posted by Engine Builder on 11/12/2016 14:05:41:

Just been looking for a suitable motor for this project. The one in the article is said to be 24 kg/cm torque but looking at the source metioned I cannot see one with that specification.

I am confused too about the voltage rating of these motors. I assume a 12v is needed as that is the supply voltage.

The one closest to the specified one has a rated voltage of 3v and the one used in the Liming article seems to be 8.6.

i am confused what to get!

Steppers often have a supply voltage higher than the supply used, if the driver uses pulse-width-modulation this allows a high-voltage peak to overcome the inductance of the winding is and get better motion. A bit like how PWM control is smoother for slow running on model railways than lowering the driving voltage.

Neil

[Engine BuilderParticipant @enginebuilder]

Posted by Neil Wyatt on 11/12/2016 14:17:39:

Posted by Engine Builder on 11/12/2016 14:05:41:

Just been looking for a suitable motor for this project. The one in the article is said to be 24 kg/cm torque but looking at the source metioned I cannot see one with that specification.

I am confused too about the voltage rating of these motors. I assume a 12v is needed as that is the supply voltage.

The one closest to the specified one has a rated voltage of 3v and the one used in the Liming article seems to be 8.6.

i am confused what to get!

Steppers often have a supply voltage higher than the supply used, if the driver uses pulse-width-modulation this allows a high-voltage peak to overcome the inductance of the winding is and get better motion. A bit like how PWM control is smoother for slow running on model railways than lowering the driving voltage.

Neil

It seems the other way around here though. The motors specified have a voltage less than the supply voltage.

[Carl Wilson 4Participant @carlwilson4]

The rated voltage of the motor will produce the rated current in the windings if applied gradually. we are applying pulses at a fairly rapid rate, so the inductance of the windings tends to prevent the full current building up. So we apply 12 volts to ensure that full current can flow.

The torque of the motor used is near as damn it 2 Nm. 1 kg cm is about 0.09 Nm. So 23 kg cm is roughly 2 Nm.

Edited By Carl Wilson 4 on 11/12/2016 15:12:25

[Neil WyattModerator @neilwyatt]

Posted by Engine Builder on 11/12/2016 14:30:24:

Posted by Neil Wyatt on 11/12/2016 14:17:39:

Posted by Engine Builder on 11/12/2016 14:05:41:

Just been looking for a suitable motor for this project. The one in the article is said to be 24 kg/cm torque but looking at the source metioned I cannot see one with that specification.

I am confused too about the voltage rating of these motors. I assume a 12v is needed as that is the supply voltage.

The one closest to the specified one has a rated voltage of 3v and the one used in the Liming article seems to be 8.6.

i am confused what to get!

Steppers often have a supply voltage higher than the supply used, if the driver uses pulse-width-modulation this allows a high-voltage peak to overcome the inductance of the winding is and get better motion. A bit like how PWM control is smoother for slow running on model railways than lowering the driving voltage.

Neil

It seems the other way around here though. The motors specified have a voltage less than the supply voltage.

Oops got my description back to front!

Most stepper driver chips limit CURRENT making the actual voltage relatively unimportant, within limits.

[Engine BuilderParticipant @enginebuilder]

Posted by Carl Wilson 4 on 11/12/2016 15:08:31:
The rated voltage of the motor will produce the rated current in the windings if applied gradually. we are applying pulses at a fairly rapid rate, so the inductance of the windings tends to prevent the full current building up. So we apply 12 volts to ensure that full current can flow.

The torque of the motor used is near as damn it 2 Nm. 1 kg cm is about 0.09 Nm. So 23 kg cm is roughly 2 Nm.

Edited By Carl Wilson 4 on 11/12/2016 15:12:25

So was it model number SY57STH76-2004A?

[Carl Wilson 4Participant @carlwilson4]

Short answer = Yes, that will do admirably.

Carl.

[Engine BuilderParticipant @enginebuilder]

The stepper motor driver arrived today.

Looking at the connections shown in the magazine article and the original article the wiring diagram was taken from I notice misleading information.

The article shows the 12v power connected to Arduino terminals gnd and vdd. There is no vdd terminal on the Arduino it is in fact vin.

The 12v supply to the driver board is shown as gnd and VMot. Again there is no VMot terminal, well not on my board, It should be gnd and +24.

In the article too there is no mention of what the DIP switches should be set to for stop current, excitation mode and decay setting.

Just mentioning this in case anyone else is confused.

[BazyleParticipant @bazyle]

Catching up with this it looks like I was well off in assuming it had an interpreter. Good detective work chaps, sorry for misleading you.. If it can work on Linux I must see if I can run the IDE on a Pie then I can play with one at work.

[Author]

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