ElectroTool Development Instrument

Simple Analog/Digital SigGen & Sig Measure Tool

This is a small yet highly versatile signal generator and measurement device.
Powered by a standard Micro USB power source.

Quite a few common digital signals are generated along with modes to generate dual analog waveforms with an adjustable phase shift.  We also have a voltmeter mode and a settable DAC output for 0-3V levels on 2 different DAC outputs.

The idea of this unit is to supply extremely common digital and analog signals as well as some basic measurement modes as a general purpose quickie development tool. 

The Esp-32 board by Mark-Toys is the brain and is behind the display in this picture.

There is a 1.3" OLED display for easy user feedback and a set of controls to allow setting of the main mode for the signal and then parameters that apply for that mode such as frequency or period/duty cycle.

A 'Function' knob selects the mode of the ElectroTool and a few controls apply based on mode 

SIGNAL GENERATION MODES AVAILABLE
   - Analog Sine, Triangle, Sawtooth and Square of 1hz to 3khz centered on 1.5 volts.
      Each of the analog modes supplies 2 waveforms with an adjustable phase offset.
   - Analog Signal synthesizer based on AD9833. Precision, stable freq sine 1-40khz
   - Digital 50% duty cycle Square Wave of variable frequency from about 75hz to 3khz
   - Digital variable duty cycle pulse train of variable freq and duty cycle
   -  A PWM signal for Servo motor checkout or positioning.  Typ 65hz  3-45% duty
   - Digital pulse wave for 1 to 99% pulses and adjustable frequency
   - A One-Shot mode triggered by button for 5us to 6msec pulses. Will auto-repeat.
      This is in both low going and high going pulse modes.
   - A Quadrature A,B set of square wave signals with variable frequency
   - A Three phase quadrature signal used to simulate 3-phase wheel encoder signal

SIGNAL MEASUREMENT MODES AVAILABLE
   - Digital Pulse Counter that is reset using pushbutton switch
   - Digital Frequency Counter measures pulses per second. Manually set a gate interval
   - A low accuracy voltmeter for 0 to 12 volts
   - Two adjustable DAC outputs from 0 to 3V.  Set in voltmeter mode with Freq and Duty
      The DAC outputs will remain unless one of the analog waveform modes is entered.
 
Controls (These Vary By Mode In use)
   - Function:     A potentiometer used to select the mode of the ElectroTool
   - Freq:  The frequency for the signal.  Rarely used for another parameter like DAC out V
   - Duty: Pulse duty cycle, Servo duty, fine tune freq for synth.
   - Trigger:       Single pulse trigger for pulse mode with auto repeat or to reset pulse counter
   - Hold:  This holds the current setup and runs clean signal. (if not small signal disruptions)
   - Mult:  A future feature perhaps for ranges

INPUTS AND OUTPUTS
  - A micro USB jack supplies power to the unit. Does not implement USB.
    A battery carrier under the case holds a thin 5V battery pack for portable use.
  - The main output can be analog or digital (3.3V signals for both).
  - The Signal Type switch selects if the main output is analog or digital
  - A ground jack is spaced from the output for standard dual bananna jack spacing
  - An input jack allows for voltmeter or frequency meter input
  - An 8-pin mini-terminal strip supplies Gnd, 5V, 3.3v Analog 2 out, digital 2 and 3 out
  - A 3.5mm stereo jack supplies the analog synth audio output of about 1 V P-P

The Mark-Toys Esp32 Dev board is used and the code is in Arduino IDE form for Esp32

ElectroTool