pslab-hardware

This repository holds PSLab Hardware design files. PSLab is a tiny pocket science lab that provides an array of equipment for doing science and engineering experiments. It can function like an oscilloscope, waveform generator, frequency counter, programmable voltage and current source and also as a data logger. The first version of hardware (V 1.0) is developed by Jithin B P, a core developer of PSLab Project.

Communication

Our chat channel is on Gitter here: https://gitter.im/fossasia/pslab

Pocket Science Lab Prototype	Front Silk Design

Content of Repository

• Technical Reference Document: Latex files
• Kicad Schematics, Layouts
• Dimension vectors
• Label vectors
• Accessory development files

Platform

• Microcontroller Platform : PIC24EP256GP204
• IDE: MPLABX IDE v3.35 (Supported on Linux/Windows/Mac)
• Compiler: MPLAB® XC16 Compiler
• Programming Tool: PICkit™ 3 In-Circuit Debugger/PICkit2

KiCAD PCB front-side	KiCAD PCB back-side

Parts list

• PIC24EP256GP204 - Main uC
• MCP6S21 - Programmable Gain Amplifier
• MCP4728 - 4 channel DAC
• TC7660 - Charge Pump voltage invertor
• TC1240A - Charge Pump voltage doubler
• TL082 - 2 channel Op-Amp
• LM324 - 4 channel Op-Amp
• LM1117 - 3.3 V regulator
• MCP2200 - USB-UART Bridge
• or ESP8266 (ESP-12E) - UART-TCP bridge
• 0.5 A Fuse
• 100K Potentiometer
• Assorted resistors, capacitors & diodes

Hardware Specs

• 4-Channel, up to 2MSPS Oscilloscope. Software Selectable amplification stages
• 12-bit Voltmeter. Programmable gain. Input ranges from +/-10 mV to +/-16 V
• 3x 12-bit Programmable voltage sources/ +/-3.3 V,+/-5V,0-3 V
• 12-bit Programmable current source. 0-3.3 mA
• Supports Advanced Plugins/Add-on Modules
• 4-Channel, 4 MHz, Logic Analyzer
• 2x sine wave generators. 5 Hz to 5 KHz. Manual amplitude control for W1
• 4x PWM generators. 15 nS resolution. Up to 8 MHz
• Capacitance Measurement. pF to uF range
• I2C, SPI, UART data buses for Accel/gyros/humidity/temperature modules etc

Firmware

The firmware is available here: https://github.com/fossasia/pslab-firmware

Feature list for the acquisition and control

Oscilloscopes

One of the main features of PSLab is the 4-channel oscilloscope which can monitor analog inputs at maximum of 2 million samples per second. It includes controls such as triggering, and gain selection. Uses Python-Scipy for curve fitting.

Waveform Generators

• W1 : 5 Hz – 5 KHz arbitrary waveform generator. Manual amplitude control up to +/-3 Volts
• W2 : 5 Hz – 5 KHz arbitrary waveform generator. Amplitude of +/-3 Volts. Attenuable via software
• PWM : There are four phase correlated PWM outputs with maximum frequency 32 MHz, 15 nano second duty cycle, and phase difference control.

Measurement Functions

• Frequency counter tested up to 16 MHz.
• Capacitance Measurement. pF to uF range
• PSLab has several 12-bit Analog inputs (function as voltmeters) with programmable gains, and maximum ranges varying from +/-5 mV to +/-16 V.

Voltage and Current Sources

• 12-bit Constant Current source. Maximum current 3.3 mA (subject to load resistance).
• PSLab has three 12-bit Programmable voltage sources/ +/-3.3 V,+/-5 V,0-3 V . (PV1, PV2, PV3) controls

Main Control Panel

Other useful tools

• 4MHz, 4-channel Logic analyzer with 15 nS resolution.Voltage and Current Sources
• SPI, I2C, UART outputs
• On-board 2.4 GHz transceiver for wireless data acquisition. (Work in progress..)
• Graphical Interfaces for Oscilloscope, Logic Analyser, streaming data, wireless acquisition, and several experiments developed that use a common framework which drastically reduces code required to incorporate control and plotting widgets.
• PSLab also has space for an ESP-12 module for WiFi access with access point / station mode.

Advanced Controls

• Advanced Controls with Oscilloscope
• Data Logger
• Wireless Sensors (Work in progress…)
• Logic Analyzer

Block Diagram