I am pretty new to this, I am looking for a way to measure the thrust of a rocket motor, so I ended up looking at a Micro Load Cell ( robotshop.com/en/micro-load-cell-50-kg.html ).
As I understand it is possible to have a USB interface for it using a Phidget Bridge ( robotshop.com/en/phidgetbrid … rface.html ).
But I want to use a raspberry PI to record all the flight data, and was wondering if there was a way to connect the micro load cell to the PI directly (via the GPIO for example).
My knowledge of robotics is very limited, I have used PWMs to control motors before but that’s pretty much all.
Also I want to removed the PhidgetBridge because it’s a bit expansive and in a perfect world rockets would never crash but that’s not the case in the real world, every flight will be very expansive if I have to buy a $100 bridge everytime somethings goes wrong…
Where will you put the load cell in the rocket in flight? Or will it just be on the test bed?
The bridge uses USB, so the Pi will need to have a USB master or on-the-go interface. No documentation on the Phidget that I saw, so you’ll need to find code to run on the Pi.
There’s a reason the Phidget is expensive. Low level signals are hard to handle, and unless you’re an experienced analog and/or instrumentation engineer, the Phidget would be difficult to duplicate.
As Alan said, the low-level voltage from the load cell (full Wheatstone bridge) cannot be interfaced to the Pi directly and needs an instrumentation amplifier.
If you want to read data from only one load cell, we recommend that you check out RB-Dfr-519. It is a much cheaper alternative that will perform just what you need. You can read the data from the board from its serial interface.
You can check the documentation here for more details.
