I am building a fly fishing furled leader machine. This machine will twist threads into a rope type of leader used in fly fishing. I need to be able to do two things. The first is easy, I need the ability to remotely control the motor speed and to remotely switch the motor on and off and to monitor the weight/tension applied to the string as it is furled. I plan on using an arduino mini and an HX1838 IR module for remote speed control.
To measure the tension I am thinking my best solution would be to use a strain gauge module of some kind like the HX711 or NAU7802. The code and logic for these is well documented and should pose no problems. The issue I want some advice on is the strain gauge configuration itself. Most of the articles I have found use a "load cell" for measuring weight. And they have a lot of very good information, but I don't need to measure weightl in that mannor, but rather the strain or tension on a cable used to connect the weight to the threads being twisted. My gut tells me to attach a piece of thin metal in-line with the thread and the weight, mount a strain gauge on the metal and attache the leads from the strain gauge to the module. But the modules seem to require a Wheatstone bridge. So I can buy four strain gauges and build a wheatstone bridge with one on the metal strip and the other three on an unstressed board. But I would rather be able to just read the strain gauge change directly and then apply the appropriate calibration to get the strain in oz/grams.
So I am open to any and all suggestions on the best method to do what I need, or a pointer to some article that might give me some ideas.
Thanks in advance. I have attached some photos of the prototype furling board I am currently using.
Why not run a cable back to where you are and just insert a spring gauge of an appropriate size. You just look at the gauge. If you want an electronic version then measure the displacement of the spring.
If you want to use load cells then look up how people have solved the problem before. This is for weighing luggage but the principle can probably be scaled down to what you need.
Look at an automotive belt tensioner.
The greater the deflection the greater the force.
Also a scale does not measure weight it measues force. SSince The pbject mass is acted upon by gravity the force can be calibrated into unots labeled weight.
There are fish reel wonders that display and regulate force
dave-in-nj:
Look at an automotive belt tensioner.
The greater the deflection the greater the force.
Also a scale does not measure weight it measues force. SSince The pbject mass is acted upon by gravity the force can be calibrated into unots labeled weight.
There are fish reel wonders that display and regulate force
Thanks, understand the concept of weight vs force. Actually weight is a measurement of force. Its the mass of the object in slugs in Imperial units, and the acceleration in Imperial is 32.2 ft/sec squared. Actually kilograms are the unit of mass in the metric system, the actual unit of weight is the newton which is calculated the same way. So when we say a killogram weighs 2.2 lbs, we are actually mixing apples and oranges. A kg only weighs 2.2 pounds when acted upon by a force of 32.2 ft/sec squared or 9.807 m/sec squared. On the moon it would weight less. But I digress, I used to teach this stuff, so I apologize if I ramble.
I will have to look into the "fish reel wonders" to see if I can use them.
ardly:
Why not run a cable back to where you are and just insert a spring gauge of an appropriate size. You just look at the gauge. If you want an electronic version then measure the displacement of the spring.
If you want to use load cells then look up how people have solved the problem before. This is for weighing luggage but the principle can probably be scaled down to what you need.
I saw that luggage weight article. I dismissed it because I only need to measure weights between 400 - 900 grams. The inline digital scale is an exceptional idea. Since I will be remotely controlling the motor, I can connect the scale directly to the weight and measure the tension that way. Thanks, funny how the simplest solution always seems to be the last one considered.
