Difference between revisions of "Anchor"

From Hackstrich
(Finalized display, added a touchscreen controller)
(Added a 'trigger event' pushbutton.)
Line 17: Line 17:
 
*** Digital
 
*** Digital
 
**** Load On/Off
 
**** Load On/Off
 +
**** Event trigger switch
 
**** CC/CV mode?
 
**** CC/CV mode?
**** 2 for UI quadrature encoder  
+
**** 2 for UI quadrature encoder
 
**** 2 for touchscreen
 
**** 2 for touchscreen
 
*** MCU-integrated 10-bit ADC
 
*** MCU-integrated 10-bit ADC

Revision as of 23:37, 25 December 2010

Anchor will be an electronic current/voltage sink, for testing/characterizing power supplies and other similar tasks.

  • Desired features/specs:
    • Constant current and constant voltage options
      • Maybe constant power too?
    • Ramp-up/down automatically and track outputs
    • Pulse load to test transient response
    • 5A/100V maximums
      • 500W dissipation in a FET is a bit nuts, so it won't be 5A *at* 100V
      • 100W continuous, 500W pulse might be reasonable? Would be nice anyway.
    • Some kind of computer interface for more complicated tests/more detailed data analysis
      • USB would be easy to implement
      • Ethernet could be cool, but that seems overkill here
      • GPIB would be the traditional choice for test gear, but I've never done any work with it
  • PIC24FJ256DA210 will be used as it has all the graphics/LCD drive/acceleration built in to enable a nice colour TFT display
    • Inputs
      • Digital
        • Load On/Off
        • Event trigger switch
        • CC/CV mode?
        • 2 for UI quadrature encoder
        • 2 for touchscreen
      • MCU-integrated 10-bit ADC
        • Heatsink temperature
        • UI pot (if used)
        • 2 for touchscreen
      • I2C
        • LTC2453 I2C 16-bit ADC for current and voltage measurement
        • AR1020 I2C resistive touchscreen controller (will try to eliminate it and do it in the PIC for revision 2)
    • Outputs
      • Digital
        • 1 for a CC/CV mode relay (if required)
      • Analog/PWM
        • Output drive (to op-amp)
  • Want a graphical LCD for the output/UI, and the PIC chosen will drive a nice TFT
    • WQVGA is a nice size, can get a menu/buttons on the side and still have room for the info display
    • Likely still want the critical UI bits to be physical controls (current/voltage mode/setting)
    • The Newhaven NHD-43-480272MF-ATXI-T-1 from Mouser seems the best option for size/touch/resolution