• Strain Gauge Rosette RAW Bridge Output

    Ahmed Hefnawi (Volta)04/20/2015 at 13:49 1 comment

    I tested the strain indicator unit with a rosette, next step would be calibrating the readings with a commercial strain indicator at college.

    The readings shown on display are just the raw voltage from the Wheatstone bridges in milli-Volts, Later I'll add the rosette as well as the linear gauges equations to calculate strain using these readings, GF (gauge factor or sensitivity) which is dependant on gauge material/type and finally the orientation and bridge configuration (Full-Bridge / Quarter-Bridge).

    In my case all the channels are quarter bridges with 120 Ohm SMD resistors.

    Awaiting feedback =)

  • PCB soldering & testing

    Ahmed Hefnawi (Volta)04/14/2015 at 23:21 0 comments


    I just finished soldering all of the components to the PCB and I found out I missed a track from Teensy's VIN to the VCC of the display and all I got was the backlight LED, after a little troubleshooting with the multimeter continuity mode and reviewing my designs I added a wire (the yellow one in the photos below) going from VCC to VIN and it worked!

    Btw this is my 1st try with a hot air soldering station and it went great, I used it to solder the 120 Ohm SMD resistors on the board. The rest of the components were soldered using a normal iron.

    Here are some photos along the way, enjoy!

  • SeeedStudio's PCBs delivered!

    Ahmed Hefnawi (Volta)04/14/2015 at 16:49 2 comments

    Just received my PCBs from SeeedStudio Fusion PCB service, the finish and the silkscreen are great. This is my first order with them.

    Here is a photo of the PCBs and next to it is the home made version (using photoresist method).