Implementation of a digital multimeter using basic stamp2 on a professional development board. It also includes R2R ladder network for digital to analog conversion

1. IMPLEMENTING A DIGITAL MULTIMETER MAE 576 [MECHATRONICS] LAB-2 GROUP E Chembrammel Elavunkal Srinivasan Vishwajeet University at Buffalo, Mechatronics, Spring 2010

5. HARDWARE OVERVIEW University at Buffalo, Mechatronics, Spring 2010 Professional Development Board (PDB) A Power switch L L293D high-current quad half-H driver B 2.1 mm power connection, centre positive, input voltage 6-12 VDC M Eight active-low push-buttons with 5V pull-ups C Serial programming interface, DB-9 N Eight active-low DIP switches with 5V pull-ups D BS1-IC, BS2-224, BS2-40 and Javelin Stamp sockets O Pulse generator with 1Hz, 10Hz, 100Hz and 1 kHz selectable output E BS1 Serial Adapter connection P RJ-11 connector for X-10 or 1-Wire I/O F Sixteen blue discrete LEDs Q MAX232E RS-232 DCE line driver G Five blue 7-segment LED displays R DS1307 I2C real-time clock with 3V battery backup H Parallel LCD interface with contrast pot (4/8-bit modes supported) S SX28AC/DP socket I Two servo headers (can also be used for Parallax Serial LCD displays and PING))) sensor) T SX-Key/SX-Blitz programming connection J Two 10K potentiometers U Solderless breadboard for connecting external components K Audio amplifier with volume control (speaker on-board/ext selectable)

6. HARDWARE OVERVIEW University at Buffalo, Mechatronics, Spring 2010 Basic Stamp 2 (Rev. J) Module

7. HARDWARE OVERVIEW University at Buffalo, Mechatronics, Spring 2010 EEPROM Regulator Interpreter PIC16F57 [i] http://www.parallax.com/tabid/134/List/1/ProductID/1/Default.aspx Basic Stamp 2 (Rev. J) Module Name BS2-IC Package 24-pin DIP Package Size (L x W x H) 1.2"x0.6"x0.4" Environment -40 to +185 o F (-40 to +85 o C) ** Processor Speed 20 MHz Program Execution Speed ~4,000 instructions/sec. RAM Size 32 Bytes (6 I/O, 26 Variable) Scratch Pad RAM N/A EEPROM (Program) Size 2K Bytes, ~500 instructions Number of I/O pins 16 +2 Dedicated Serial Voltage Requirements 5 - 15 vdc Current Draw @ 5V 3 mA Run / 50 µA Sleep Source / Sink Current per I/O 20 mA / 25 mA Source / Sink Current per unit 40 mA / 50 mA per 8 I/O pins PBASIC Commands 42 PC Programming Interface Serial Port (9600 baud) Windows Text Editor Stampw.exe (v1.04 and up)

8. HARDWARE USED University at Buffalo, Mechatronics, Spring 2010 Component Name On PDB Y/N Part # Page # BS2 – IC Y Basic Stamp2 Module PDB - Professional Development Board Switches* Y [M] Resistors N 100Ω(3), 220Ω(1), 1kΩ(3), 2.2kΩ(5) - Capacitor N 0.1μF (1) - ADC0831 N ADC0831 (8-bit Analog to Digital Converter) LM358N N LM 385 (Op-Amp) LCD Display N 2 x 16 Parallel LCD

15. PROCEDURE [Flow Chart] University at Buffalo, Mechatronics, Spring 2010 Flow Chart

16. PROCEDURE [Circuit] University at Buffalo, Mechatronics, Spring 2010 Circuit

17. PROCEDURE [Pin Layout] University at Buffalo, Mechatronics, Spring 2010 Pin Layout PIN # Component Device P0 D4 LCD Data Input P1 D5 LCD Data Input P2 D6 LCD Data Input P3 D7 LCD Data Input P4 E LCD Pulse Input P5 RS LCD Command/Write P6 DataIN ADC (R-2R) and ADC (Voltmeter) P7 Clock ADC (R-2R) and ADC (Voltmeter) P8 BIT0 [LSB] R-2R Network P9 BIT1 R-2R Network P10 BIT2 R-2R Network P11 BIT3 R-2R Network P12 BTN0 Ohmmeter Button P13 BTN1 Voltmeter Button P14 BTN2 & Chip Select R-2R Mode Select & ADC(Voltmeter) P15 RC Circuit & Chip Select Ohmmeter & ADC(R-2R)

18. PROCEDURE [Source Code] University at Buffalo, Mechatronics, Spring 2010 Source Code (Attached to Webpage)

19. IMPLEMENTATION University at Buffalo, Mechatronics, Spring 2010

20. CALIBRATION-Ohmmeter University at Buffalo, Mechatronics, Spring 2010 Resistances Used (kΩ) Digital Multimeter Basic Stamp Multimeter Raw Data (kΩ) Rounded Data (kΩ) Non-Calibrated Data Calibrated Data Absolute Error (kΩ) Value (kΩ) % Error Value % Error 1.0 0.968 1.0 0.8 20.00% 0.8 20.00% 0.2 2.2 2.13 2.1 2 4.76% 2 4.76% 0.1 3.2 3.1 3.1 3.1 0.00% 3 3.23% 0.1 4.4 4.28 4.3 4.4 2.33% 4.2 2.33% 0.1 4.7 4.59 4.6 4.7 2.17% 4.5 2.17% 0.1 5.7 5.56 5.6 5.8 3.57% 5.6 0.00% 0.0 6.9 6.73 6.7 7.1 5.97% 6.8 1.49% 0.1 7.9 7.7 7.7 8.1 5.19% 7.9 2.60% 0.2 9.4 9.16 9.2 9.7 5.43% 9.4 2.17% 0.2 10.0 9.76 9.8 10.4 6.12% 10.1 3.06% 0.3 11.0 10.73 10.7 11.4 6.54% 11.1 3.74% 0.4

21. Calibration-Voltmeter University at Buffalo, Mechatronics, Spring 2010 Measurements (V) Digital Multimeter Basic Stamp Multimeter Raw Data (V) Rounded Data (V) Raw Data (V) Rounded Data (V) % Error Absolute Error (V) 0 0 0 0 0 - 0.00 0.5 0.498 0.5 0.509 0.51 2.00% 0.01 1 1.025 1.03 1.039 1.04 0.97% 0.01 1.5 1.504 1.5 1.509 1.51 0.67% 0.01 2 2.09 2.09 2.098 2.1 0.48% 0.01 2.5 2.49 2.49 2.51 2.51 0.80% 0.02 3 3.02 3.02 3.059 3.06 1.32% 0.04 3.5 3.48 3.48 3.51 3.51 0.86% 0.03 4 3.97 3.97 4 4 0.76% 0.03 4.5 4.49 4.49 4.529 4.53 0.89% 0.04 5 4.97 4.97 5 5 0.60% 0.03

22. Calibration-R2R University at Buffalo, Mechatronics, Spring 2010 Digital Increment Binary Value BIT3 (V) BIT2 (V) BIT1 (V) BIT0 (V) Expected Voltage (V) Increment of 16 2.5 1.25 0.625 0.3125 BINARY HEX 0 0000 0 0 0 0 0 00000000 0 1 0001 0 0 0 1 0.3125 00010000 10 2 0010 0 0 1 0 0.625 00100000 20 3 0011 0 0 1 1 0.9375 00110000 30 4 0100 0 1 0 0 1.25 01000000 40 5 0101 0 1 0 1 1.5625 01010000 50 6 0110 0 1 1 0 1.875 01100000 60 7 0111 0 1 1 1 2.1875 01110000 70 8 1000 1 0 0 0 2.5 10000000 80 9 1001 1 0 0 1 2.8125 10001111 8F 10 1010 1 0 1 0 3.125 10011111 9F 11 1011 1 0 1 1 3.4375 10101111 AF 12 1100 1 1 0 0 3.75 10111111 BF 13 1101 1 1 0 1 4.0625 11001111 CF 14 1110 1 1 1 0 4.375 11011111 DF 15 1111 1 1 1 1 4.6875 11101111 EF