Pocket Calculator Control Interface
Communicating with a TI-83(Plus) or TI-84 Plus
Every technician or engineer has a pocket calculator somewhere on their desk. Although the internal processes of these calculators are hardly suitable for control tasks, some of them can be used to build a nice robot.
Materials
Gerber file
CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.
Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.
The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.
Extra info / Update
• 32 ESD-protected inputs/outputs including connectivity for I2C, AVR-ISP, JTAG, RS485 and general I/O.
• Supply regulation using 7805
• Firmware all in C
• Simple to program
Component list
Resistors
R1-R5 = 4k?7 (SMD 0805)
R6,R15 = 47? (SMD 0805)
R7-R14 = 1k? (SMD 0805)
Capacitors
C1-C5 = 100nF (SMD 0805)
C6,C9 = 18pF (SMD 0805)
C7,C8 = 10?F 50V
Semiconductors
D1 = SM4007
D2,D4 = 8.2V zener diode
D3,D5 = 4.7V zener diode
IC1 = not fitted
IC2 = ATmega32-P, programmed
IC3 = 7805DT
IC4 = MAX487CSA
PB1-PB8 = LED (SMD 0805)
Miscellaneous
L1 = 10?H
Q1 = 8MHz
PORTB,PORTD,JTAG,ADC = 10-way boxheader
ISP,I2C = 6-way DIL pinheader
POWER,RS485 = PC terminal block, lead pitch 5 mm (0.2”)
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