Member postings for Peter Bell

Ive also put a small washer under the spring "legs" to increase the force if they are slipping. Useful if your trying to eliminate a problem.

Peter

Thanks for the advice.

Think it may be easier/quicker with my limited knowledge to go down the SD card route so I've ordered them also some extra nano's--seem to have run out

Any reccomendations on temp? Got some DS18B20 but think I remember reading they were very slow, also got some TC74 to hand?

Perhaps I can use the if statement where the pulse is generated as the tick after the threshold is reached?

Peter

#define THRESHOLD 10
#define PUSH_TIME 30
#define A_PIN A0

int led = 13;

void setup() {
pinMode(A_PIN,INPUT);
analogReference(INTERNAL);
pinMode (13,OUTPUT);

}

void loop() {
if (analogRead(A_PIN) > THRESHOLD) {
pinMode(A_PIN,OUTPUT);
digitalWrite(13, HIGH);
digitalWrite(A_PIN,HIGH);
delay(PUSH_TIME);
digitalWrite(13, LOW);
pinMode(A_PIN,INPUT);
delay (300);
}

}

My pendulum seems to be happily running and its coming out at around 0.8 sec/ swing.

Not sure if I should be asking this but here goes! Its a mild steel rod and bob in free air.

If I wanted to get some simple data from it s rate would it need to beat seconds?

What would equipment would I need to do this?

Dont have a PC in the workshop.

Peter

Thanks for the history of Archdale Mark.

I have an Archdale radial arm drill circa 1921 which I bought from a factory closure sale in Birmingham. Great machine, pleasure to use with all the controls to hand.

It was in a store room partially buried. I bought the complete room and and demolished a wall to get it out selling most of the other contents of the room. I recruited 2 scrap men with a useful Hiab lorry to get it home and as we were gently pushing the drill through the factory delicatley balanced a pallet truck we were constantly heckled by people wanting to buy it, lots had looked at it but were more cautious than me about buying it and getting it out of the room.

Peter

John, Yes I have a similar arrangement but also enabled pin 13 on and off to flash as the Arduino is remote from the pendulum, can see its working---very much work in progress! I thought of simple amplitude adjustment by using selective resistor if needed. The original sketch is a very neat arrangement, would have liked to sample something to give amplititude control as on my other clock but cannot think of a way at the moment without adding another sensor which I dont want to do.

I deliberatly left the rod length short for a 1 sec beat as I was going to use the compound part to adjust it to 1 sec or more, think its about 0.75 secs now but needs reworking to make a double suspension spring arrangement to give it enough stability .

Inspired by John's clock I eventually got round to trying the simple Arduino based driver which is described earlier in the other thread on a simple pendulum left hanging from a previous failed compound pendulum experiment. It has a an ironless wound core and the pendulum rod swinging over it has a small powerful magnet attached to the end. Pic below shows it swinging, nothing connected all as per the pic in the original article.

I used the sketch intact from the link and the pendulum worked first time, swinging away nicley, very pleasing. However after leaving it for a while when I went passed I could hear knocking with the pendulum swinging wildly. The knocking turned out to be the top suspension rod hitting the suspension bracket, not good.

Put the scope on again and I could see multiple actuations from the coil. The pulse width was set at 30ms but I could see 5 x 30ms = 150ms, no wonder it was going a bit wild.

Tried various settings on the sketch also playing with the limiting resistor which improved things. I realised that the multiple pulses were caused by the threshold voltage being seen on the rising part of all the cycle so modified the sketch slightly and its now on got one 30ms pulse and seems very happy. The pendulum duration is around 3/4 secs.

Peter

Dave, Good to get the report on your clock., that TCXO looks a challenge.

I'm interested in seeing how you get on with the Nano Every. I bought a couple last year but I've never managed to get them to run anything more than Blink.

Just plugged it in to remind me of what the problem is and got a message saying I needed a download into the library for the Every etc. Did this but still no good after configuring boards in tools etc. Gave one to a very knowledgable friend but he gave up as well so I'm looking forward to finding out what I've got wrong when yours works!

Peter

I'm with SOD on this one and I'd be a bit suspicious of the 100R and cap in series,. Think its called a snubber and Iv'e come across a few of them over the years which have broken down in a spectacular way and left traces of burning in the process.

Occasionally on things like this Ive connected them ito the mains in series with a high wattage bulb or 1 bar electric fire to limit the current which has allowed me to see whats going on without too many distractions from blowing fuses and other dramas.

Peter

May thanks for all the help and suggestions.

Tried them without success, however after reading the other thread on Arduino displays and following the suggestion from SOD I felt inspired enough to start looking up what I had on the 7219 which gave limited success due to my lack of knowledge before being abandoned 2 years ago.

This time around from what I have learned I managed to work out what I was doing wrong and ended up with a working 7219 display on my weighing scale. This is my code below.

The Adafruit display worked immediatly and its nice and large and bright so good suggestion.

Next challenge is to explore storing and then retrieving a float value, can anyone reccomend an easy way or good tutorial etc?

I keep hearing about wearing out eproms, is it best to store things like that on an SD card?

Peter

#include <HX711_ADC.h>
#include <Wire.h>
HX711_ADC LoadCell(4, 5);
#include <HCMAX7219.h>
#include "SPI.h"
#define LOAD 10

const int Reset = 3;
float weight;
HCMAX7219 HCMAX7219(LOAD);

void setup() {

Serial.begin(9600);

HCMAX7219.Init();
HCMAX7219.Clear();
HCMAX7219.print7Seg("27-11-20",8);
HCMAX7219.Refresh();
LoadCell.begin();
LoadCell.start(2000);
LoadCell.setCalFactor(851.58);
pinMode( Reset,INPUT_PULLUP );
}
void loop() {
LoadCell.update();
float i = LoadCell.getData();

Serial.println(i,1);

HCMAX7219.Clear(); /* Clear the output buffer */

HCMAX7219.print7Seg(i,1,4,4); /* Write some text to the output buffer */

HCMAX7219.Refresh(); /* Send the output buffer to the display */

if ((digitalRead(Reset) == LOW)) { //Tare

HCMAX7219.Clear();
HCMAX7219.print7Seg("TARE",4);
HCMAX7219.Refresh();
LoadCell.tare();
delay(500);
}
//delay (1000);
}

Thanks for the help Dave. Tried all the 3 alternatives but still got the same result I'm afraid. Also tried another display just in case this one is a dud or not what it's marked with identical results.

Think its time to put this display aside and wait until the ones arrive that were suggested earlier in the thread, sure they will bring new problems to the surface and then more learning.

Peter

Thanks for the suggestions.

Tried thems in many combinations including baud rate but didnt make any difference,

When read i instead of weight got the display to do something, see attached reading a 1kg weight , no weight just flashes the decimal places.

Put the lcd back as it doesnt seem to be the culprit.

Tried another display with identical results, perhaps its time to give up and wait for the I2c display and other to arrive!

#include <MD_Parola.h>
#include <HX711_ADC.h>
#include <Wire.h>
#include // LiquidCrystal_I2C library
HX711_ADC LoadCell(4, 5); // parameters: dt pin, sck pin
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); // 0x27 is the i2c address of the LCM1602 IIC v1 module (might differ)
#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define MAX_DEVICES 4
#define CLK_PIN 13
#define DATA_PIN 11
#define CS_PIN 10
MD_Parola P1 = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

const int Reset = 3;
//float weight;

String J;

void setup() {
P1.begin();
Serial.begin(57600);
lcd.begin(16, 2);
lcd.print(" Starting ";
lcd.setCursor(0,1);
lcd.print(" 20/11/20 ";
LoadCell.begin();
LoadCell.start(2000);
LoadCell.setCalFactor(851.58); // calibration factor for load cell => strongly dependent on your individual setup Higher for less
pinMode( Reset,INPUT_PULLUP );// Pin3 pull up
lcd.clear();
}

void loop() {
LoadCell.update();
float i = LoadCell.getData();
lcd.setCursor(3,0);
lcd.print("Weight[g]:";
lcd.setCursor(6, 1);

Serial.println(i,1);

J=String(i);
//P1.print(J);

P1.print( J.c_str() );
lcd.print(i,1);
lcd.print (" ";

if ((digitalRead(Reset) == LOW)) {
lcd.setCursor(0, 1);
lcd.print(" Tare ";
LoadCell.tare();
delay(500);
lcd.clear();
}
//delay (1000);
}

Edited By Peter Bell on 23/11/2020 18:47:21

Edited By Peter Bell on 23/11/2020 18:48:13

Sorry forgot to say---yes working fine

Got rid of all lcd but no difference I'm afraid....

This is my working sketch at least for weighing and LCD display--must have got it wrong as I cannot make the Parola do anything? Inserted what I think but probably not in the right place! Certaily takes a lot of memory.

Can make the 7219 scroll from other sketches so the module is working.

#include <MD_Parola.h>
#include <HX711_ADC.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h> // LiquidCrystal_I2C library
HX711_ADC LoadCell(4, 5); // parameters: dt pin, sck pin<span data-mce-type="bookmark" style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;" class="mce_SELRES_start"></span>
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define MAX_DEVICES 4
#define CLK_PIN 13
#define DATA_PIN 11
#define CS_PIN 10
MD_Parola P1 = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

const int Reset = 3;
float weight;

String J;

void setup() {
P1.begin();
Serial.begin(9600);
lcd.begin(16, 2);
lcd.print(" Starting ";
lcd.setCursor(0,1);
lcd.print(" 20/11/20 ";
LoadCell.begin();
LoadCell.start(2000);
LoadCell.setCalFactor(851.58); // calibration factor for load cell => strongly dependent on your individual setup Higher for less
pinMode( Reset,INPUT_PULLUP );// Pin3 pull up
lcd.clear();
}

void loop() {
LoadCell.update();
float i = LoadCell.getData();
lcd.setCursor(3,0);
lcd.print("Weight[g]:";
lcd.setCursor(6, 1);

Serial.println(i,1);

J=String(weight);
P1.print(J);


lcd.print(i,1); //Prints weight rounded to 1 place
lcd.print (" ";

if ((digitalRead(Reset) == LOW)) { //Tare
lcd.setCursor(0, 1);
lcd.print(" Tare ";
LoadCell.tare();
delay(500);
lcd.clear();
}
//delay (1000);
}

Malc, I'm in the same boat really but about 2 years in front! Thanks to help from this forum I've made good progress but original thinking on sketches is always a problem for me.

I found that "Programming Arduino" getting started with sketches and "Next Steps" both by Simon Monk were a great help but perhaps you are further on from that, they include examples to play with as well as descriptions of the sketches.

I found it useful if I could add lcd and serial prints to sketches to see what was happening but certainly plenty of Arduino around, parts and knowledge once you can manage the IDE.

Peter

Many thanks for the help, hesitated asking but pleased I did! The power of this site is amazing.

Never heard of an I2c backpack so ordered some Adafruit bits also a TM1637 to try. Nice tutorial on the Adafruit.

Meanwhile Ady I'll have a go with the Parola suggestion but looks far more than what I need. Copied the code and got it to compile after adding some curly braces. Added to my weighing sketch but its doing some funny things with the Max display, need more time to play, hopefully later.

Hello Not really model engineering but at least I'm using my Myford to make the parts!

As a fairly inexperienced Arduino user I am building a dedicated weighing scale using a 1kg load cell.

Its all working fine using a lcd display but what I would like is use a larger display and this where it gets difficult as there so many variations to choose from. Tried a max 7219 without much success also some tft but all seem difficult to use, at least for me!

Can anyone reccomend an easy to use current larger display that worked for them, say 1.8" or 2.2"?

Thanks Peter

Clive,

Thanks for the explanation--its all new to me so I found it very interesting after finding it on the web. From the info the plant looks quite large at 50Mw so expect the compressor (or multiples) and cooling to be big. Is the compressor normally a 3 stage piston type? Seems frightening pressures to me!

Once the air is a liquid can it be stored in an insulated container and what would the pressure be?

Peter

Not much to add all well covered but I know on bigger loco's if the piston alignment as set by the crosshead is out it can give funny noises as the piston is rubbing the bore especially when running slow. Occasionally piston rings can make similar noises, strip down and they look fine, reassemble just the same!

Peter

Many thanks for the replies. Before I can do anythingI need to do is move my clock from the workshop near to where the pc lives, easier said than done, working on it but other things are to do first!

What I was hoping was extract the timings from the bdc sensor negative going pulse in the blue trace and see the speeding up and slowing down of the pendulum as the actuating coil switches. I've got a Microset and sensors, nice bit of kit but never had much success with it.

Peter