# Hardware To Software

Theory, hardware, software and code

## Liquid Filling Machine – Liquid Filler Part 4

Liquid Filler 3D

We have already seen till now how we have constructed our project in PCB .
Liquid filler at this point needs calibration.
The first step is to dimension correctly the RG resistor.
From the weight sensors article we already know that :
a) For a 1Kg load cell we are going to need Gain=1,07421875/0,005473=196 for a 1.1V arduino reference analogReference(INTERNAL); So we need a Rg=312 Ohm.

b) For a 20Kg load cell we need a Gain =  3925 for a 1.1V arduino reference analogReference(INTERNAL);
So we need a Rg=15 Ohm.

October 27th, 2011 at 1:27 pm

## Liquid Filling Machine – Liquid Filler Part 3

Liquid Filler on PCB

In the last two articles we have worked on the breadboard.
We have seen that the circuit worked well so we need to construct it in PCB and then calibrate it.
Then we will construct a weight board with the load cell installed on it.
Once done with this step then we should be able to calibrate the device.
The calibration will be discussed in a next article.

October 26th, 2011 at 3:46 pm

## Liquid Filling Machine – Liquid Filler Part 2

In the first part of liquid filler we have made the user interface.
Now it is time to add the relay and the weight sensor.
We will keep working on our breadboard.
In this article we will see how to connect the relay then our load cell amplified by the INA125 and lastly the modified code from the last time.

It is highly recommended to read the relay article and the weight sensors introduction before you start.

October 24th, 2011 at 4:44 pm

## Weight sensors and arduino

Analog to digital converter

A sensor is usually an analog device. Analog devices are connected at the analog ports of arduino.
Arduino  with the use of AnalogRead function can read the analog sensor value from the specified analog pin.
The Arduino board contains a 6 channel 10-bit analog to digital converter. A 10 bit analog to digital converter as we have seen in the “Binary Decimal and Hexadecimal numeral systems” equals to a 210 – 1 = 102410  (0-1023 => 1024 steps).
If the resolution of arduino (1024 steps) does not cover your project you should use an external ADC converter with more that 10 bits.
For example you can connect the LTC2400 ADC which happens to be a 24 bit analog to digital converter.