Newbie to controllers & all, need to test props & chose DJI phtm 2 as the std, so just using a motor for static stand and need to know rpm & current-wattage for a prop, doesn’t need to store data at first, just a readout ok.
I was assuming to buy the DJI controller so the question is what the setup in parts etc. from the controller to readout rpm & watts would be as the focus not as part of a copter?
So new welcome url’s to references and all.
[edit #2, using arduino r3 & just found adafruit motor shield v2.3 looks fitting so I think my question is now do I need the DJI controller??? ]
thx, tom
Hi Tom,
You need to build a Propeller test stand but what do you need to test exactly ?
Most of the similar test-bench use a way to get Thrust data more than anything.
For what you suggested, you need a current and RPM sensor. To make the motor turn you do need a Brushless motor controller.
You than need to interpret and calibrate all those sensors and display the information an a LCD.
The Adafruit shield will not be able to drive a brushless motor, only Brushed and Stepper.
Your controller need to match the Motor and Voltage of your setup.
Thanks Eric, in between found out about the motor so looking at using Sparkfun board & motoproto shield instead, open to advice.
For metrics will look for a rpm counter, current & windspeed also to measure actual flow velocity from the wing, aka thrust.
Typical load cells at the ends of a frame with the motor at the center to tune for balance & get metrics for each, going for low vibration, final part is adding actuator arms for automatic balancing.
Downloaded arduino & learning basics, url’s to code samples welcome for what this needs.
One of the cheapest way to control a Brushless motor is with a R/C motor controller.
They use PWM signals to control, just like a R/C servo.
UAV & Drone ESCs / Speed Controllers
We also have one other board which is more “Robot” based:
Veyron 5A Brushless Motor Controller
If you are using a Load-Cell for the trust, you can look at a shield:
Strain Gauge / Load Cell / Wheatstone Amplifier Shield
Load-Cells Sensor
Cool, will do that for the motor, now looks like I’ll use one with shaft both ends to give more options & fit the board, yeah, the brushless board is better with the DJI idea but my props have an insert for the shaft, saw one 7,700rpm in stock seems to have a through shaft, prefer to avoid gearing in the motor for testing.
I should be able to diff the legs to get rpm original tho’t, I’ll be using a pair for x, one for y and both pairs for z or thrust, with a shield per pair seems high-resolution, this diff will drive actuators with sanders to balance the blades.
Then, I like IMU’s, they look useful not sure how to set it up, it’d be nice having rpm acceleration, current & thrust for dead-lift efficiency. Got to where the stand is on rails to do dead-lift using weights so far.
thx
Progress, I found a simple rpm sensor for brushless motors, very reasonable price uses a motor lead to count exactly what I hoped for & $15 !!!
Then best fit for range are 5kg load cells and there individual bridges vs a 4-input PhidgetBridge Load Cell / Wheatstone Bridge Interface to process the signals.
My theory is having 4 for a force across the shaft axis it’ll add strain to one and subtract it from the other to diff for better resolution than just two sensors, not sure on that seems it’d give polar resultant vectors.
I like the 4-input, it’s only $20 more so asking for experience with them for this idea, the total load hovering for a DJI is 3-lbs/1.4kg, to overcome inertia a guess is double that in how they rev then take-off to hover before flying.
That seems plenty of resolution to drive servos with strip-belt sanders the end goal.
Simplifying, the 3-axis gyro is simple and with a breakout board easy to build on a desk so changed to just doing force testing and get it running this week to start improving performance; it’ll mount on a sliding assembly.
cheers!
