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Firmware

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Files

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File

Note

calibration.ino

First test firmware by Thomas Sanladerer, it sends the ADC raw value over I2C, insert some drills of known diameters into the sensor and note the ADC value, then put the values into driver.ino and re compile

driver.ino

Code for the sensor, it uses a hardcoded table to convert the ADC to Diameter, and sends 2 bytes over I2C – no analog out

host-example.ino

Reads the 2 bytes of diameter over I2C, and displays it over the UART, used to test the sensor

Host_ee_prog.ino

Code for the Host Arduino, uses bidirectional communication with the sensor and has a simple UART Console to do the calibration and sensor testing

Infidel_release_ee.ino

Firmware for the sensor, table in EEPROM, sets values over I2C

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Setup and Programming

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Requirements

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Load the code, wire the ISP program to the ISP port on the sensor and program it.

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Remember to set the processor to Attiny85.

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Tools –> Processor: Attiny85

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Tools –> Clock: Internal 1 MHz

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Tools –> Burn bootloader to set the fuses

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Sketch –> Upload with Programmer

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After programming, the LED should flash two times.

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Wiring to the Host Board

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Wire Diagram

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Connect the the sensor to the host board, such as an Arduino Uno or Mega.

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Program the Host with Host_ee_prog.ino and start the console with 19200 baudrate.

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Console

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On start, the following is shown:

+
Infidel Sensor Programmer
+Scanning...
+I2C device found at address 43
+
+Version: 3.12
+Table [ADC] [DIA in um]:
+00: 0000 / 3000
+01: 0619 / 2090
+02: 0702 / 1700
+03: 0817 / 1400
+04: 1000 / 1000
+05: 1023 / 0000
+Table [DAC min Uout in uV] [DAC max Uout in uV]:
+09: 1344 / 2017
+Command Input 0 - val / 1 - RAW val / 2 - Version / 3 - Table / 4 - Set Tabel Val / 5 - Ongoing raw read / 6 - sample Mean ADC Val
+Command Input 7 - DAC 0 PWW / 8 - DAC 255 PWM
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+ +++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Commands

Note

Output

0

Read the Diameter value

Diameter [mm]: 2.242

1

Read the Diameter + raw ADC Value

Diameter [mm] / [ADC]: 2.242 / RAW: 515

2

Read the Version

Version: 1.11

3

Read the Diameter Table

Table [idx] [ADC] [DIA in um]

4

Set the Value in the Table

Input values for Table [IDX],[ADC],[DIA um] like (1,619,2090)

5

Ongoing reading the ADC raw Value, stop when the command 5 is sent one more time

6

Read Meanvalue from Sensor (100 Samples), Display Min / Max / Mean / cnt, used it for Calibration

ADC Mean: 704 / Min: 688 / Max: 713 / Cnt: 100

7

Set DAC to PWM 0 –> for check Output Voltage at LOW

8

Set DAC to PWM 255 –> for check Output Voltage at HIGH

h

Show the command list

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Calibration

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Start with the bigger shaft of known diameter (e.g., 2 mm), insert it into the sensor and read the raw ADC value with command “6”. +Command “6” determines the mean value over 100 measurements and removes the outliers

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ADC Mean: 704 / Min: 688 / Max: 713 / Cnt: 100
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Note the ADC value and use the command “4”. +The console should show:

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Input values for Table [IDX],[ADC],[DIA um] like (1,619,2090)
+Input:
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Input this string: 1,503,2000 +Means, Table Index 1 (Command “3”), ADC Val 503, Diameter 3

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Repeat this for the next two Ddiameter (1,7mm, 1,4 mm) and write the values to the sensor.

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At the end check the settings with Command “3”.

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Table [ADC] [DIA in um]:
+00: 0001 / 2999
+01: 0617 / 2092
+02: 0722 / 1711
+03: 0816 / 1401
+04: 0999 / 1001
+05: 1022 / 0001
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The values are stored in the EEPROM and will load from the EEPROM at the next power up.

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If you program the sensor with a new firmware over the ISP the EEPROM will be erased and the sensor will start with default settings.

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Calibration with Button (Standalone)

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Press the Button at Powerup for 3 sec, if the Calibrationmode start the LED flashes 10 times +The sensor sends an analog signal to Pin 5 [OUT].

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  • +
    Step 1, Led Flash 1 Times
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    • Insert Drill with 1,4mm

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    • Wait a short Time, 1-2 sec

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    • Press the Button for 1 sec

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    • The Led light for 2 sec, the Sensor is getting 100 Samples from the ADC

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    • If the messure is Ok the Led flash fast

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    • Remove the drill an press the Button

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    Step 2 Led flashes 2 Times (1,7mm Drill)
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    • Insert the Drill 1,7mm and repeat Step 1

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    • +
  • +
    Step 3, Led flash 3 times (2mm Drill)
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    • Insert the Drill with 2mm and repeat Step 1

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The Calibration is done

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Analog Output

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The sensor sends an analog signal to Pin 5 [OUT].

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The range goes from 1.42 VDC to 2.14 VDC . +The voltage is the analog for the diameter: 1.73V is equal to 1.73mm diameter.

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Calibrate the Analog Output

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Connect a Multimeter to GND and OUT. +The Analog Output depend on the VCC Voltage, so make the Calibration when the Sensor is connected to the Printerboard +and not to the unstable USB Port.

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  • Set with the command “7” the PWM to LOW, meassure the Voltage on Analog OUT and note it (like 1,344 V)

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  • Set with the command “8” the PWM to HIGH, meassure the Voltage on Analog OUT and note it (like 2,017 V)

    • +
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Set with the command “4” the table Value for Index 9 (Calibration Values for DAC) +IDX 9 then LOW Voltage and the HIGH Voltage –> like: 9,1344,2017

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Check the table with command “3”. +The Values are stored in the EEPROM for the next Start

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Fault Pin

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The fault pin is high when the diameter is bigger than 3mm and smaller than 1.5mm. +This indicates that the sensor is outside of the normal working range.

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