I am working on an application where i need to convert the weight of a person to calculate and use it for other parameter. It turned out after trying with the AD insrumentation amplifier that i was not getting linear results and the readings were not accurate so i decided to use HX instead. Did you use this instructable in your classroom? Add a Teacher Note to share how you incorporated it into your lesson. First you need to open the weighing scale and get rid of the internal circuit to use the load sensors.
So the sensor gives the analog voltage as an output to the arduino but the voltage level is too small to be detected by the adc of the arduino and needs to be amplified using instrumentation amplifiers like AD or INA HX Datasheet. More info on DfRobots. More details can be found here. Still waiting for the hardware to arrive, but my sketch is ready.
With the current version of HX Hey guys, i'm doing a balance system with 4 balances to do a mass balance in a race car a project of my university.
I did all, but the balances display a wrong result. I calibrated the system individualy but when i put a 5kg mass in the balance used to calibration all display the same value, but if i mount in the balances, one same more and one same less.
I don't know what's happening, could it be the cables? Please Help me! Reply 1 year ago. You can divide it in groups of 2 and sum the results of the 2 values, then, just take the average. Question 1 year ago. Reply 2 years ago.We are still shipping! When you place an order, we will ship as quickly as possible.
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Weight Sensor / High Precision Weigh Modules
This product has shipping restrictions, so it might have limited shipping options or cannot be shipped to the following countries:. Added to your shopping cart. This load sensor, sometimes called a strain gauge, is the same one found in digital bathroom scales you know, the ones you use in January for your New Year's resolutions, and then forget about a month later.
This sensor can measure up to about pounds. Check the video below for a simple explanation on how these work and how to use them. White and black are the outer terminals with red being the center tap. The picture below will give you a good idea what the inside of the load cell looks like. Our load sensor should measure ohms between the red and white or black wires and ohms between the black and white wires.
If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code. Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available.
Sensors or shields will communicate with serial or TTL. See all skill levels. If it requires power, you need to know how much, what all the pins do, and how to hook it up.
You may need to reference datasheets, schematics, and know the ins and outs of electronics. Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements.
You will need to understand polarized components. We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page. I found the Load Sensor a bit tricky to mount properly, so I eventually designed a 3D printed part to hold it to a wooden support block.
It's loadsensorholder. This is based on the Strain Gauge?
How can i check some electrical resistance strain gauge formula couse i need that to compare efficiency. What kind of precision can you get out of these sensors if you had four of the hooked up through a combinator to your HX amp board? Can you get down to ounce or sub-ounce precision?
I'm thinking I'd like to use them to detect changes in volumes of liquids but I would need approximately ounce precision. Does anyone have any photo examples of mounting these? Like previously stated, they're tricky to attach.Skip to main content. Bathroom Scales. See Size Options. FREE Shipping on eligible orders. Add to Cart. Promotion Available See Details.
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How to use a Weight Sensor / Load Cell + HX711 with an Arduino
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Amazon Drive Cloud storage from Amazon. Alexa Actionable Analytics for the Web.Digital scales work with the use of a strain gauge load cell. Whereas analog scales use springs to indicate the weight of an object, digital scales convert the force of a weight to an electric signal. Its key components consist of a strain gauge, a device used to measure the strain of an object, and load cell sensor, an electronic device used to convert a force into an electrical signal.
A load cell is also known as a force transducer. When an item is placed on the scale, the weight is first evenly distributed. Under the flat tray of a digital scale you might find, for example, four slightly raised pegs in the corners that serve to distribute the force of the weight evenly. The mechanical design of the digital scale then applies the force of the weight to one end of a load cell. As the weight is applied, that end of the load cell bends downwards.
The force of a weight then deforms the strain gauge. The strain gauge can consist of metal tracks, or foil, bonded to a printed circuit board or other backing. When the metal foil is strained, the backing flexes or stretches. The strain gauge then converts the deformation to an electrical signal. Because the load cell has an electric charge, as it moves downwards, the electrical resistance changes. The resulting small change in resistance becomes an electrical signal. The signal is run through an analog to digital converter, and then passes through a microchip that "translates" the data.
As a result of this final calculation, numbers indicating the weight of the object appear on the LCD display of the digital scale. Marynia Kolak is an interdisciplinary writer with a science background. Her articles have appeared in the Buzz, the examiner. She has picked microfossils and constructed maps in state and federal geological surveys. Kolak received her Bachelor of Science in geology, and is a candidate in an Master of Fine Arts creating writing program.
She lives in Chicago. How Does a Digital Scale Work? By Marynia Kolak. Hunker may earn compensation through affiliate links in this story. This digital scale measures the weight of a pen cap as 0.
A load cell, type double bending beam. In this strain gauge, the blue material conducts electricity. It can be pasted onto a backing.Tutorial: How to make a weighing scale with the HX711, a load cell and an Arduino - UATS A&S #14
Two weights measure grams on this digital scale. Share this article. Marynia Kolak. Show Comments.As hardly any scales work analogously, it is of course also possible to measure weights with a digital Raspberry Pi scale.
This can be used in various applications as the weight value ranges which can be measured are also almost unlimited. Only a sensor and a load cell are required, which are available for different weight ranges. In this tutorial we are building a simple Raspberry Pi kitchen scale, whose precision is amazingly accurate.
Of course, it is also possible to unscrew an existing person scale and read it out using a Raspberry Pi. This is available for different weight classes up to 1kg, up to 5kg, up to 50kg, etc. Even though some have a different form, all are provided with four cables. To read out the values, the HX weight sensor is also required.
This sensor is available in two versions: red and green. The pressure sensors probably have small differences, but are — theoretically — both compatible. I have used the green HX Fixing material is also required. Alternatively, you can also take an existing person or kitchen scale and unscrew it. In any cases, a load cell is available and sometimes also a HX weighting sensor.
Make Your Weighing Scale Hack Using Arduino and Hx711
With this you could start directly. Since complete scales cost only slightly more than the load cells, this is definitely worth considering. Before the load cell is connected to the HX weight sensor, it should be mounted on the two plates.
For this I made markings with a ballpoint pen on the wooden boards, where the screws come in. With a drill I drilled the holes and inserted the screws. Between the screw and the load cell, there should be a nut, which serves as a protection to the board see pictures.
If the construction is complete, we can go to the HX The four cables of the Load Cell must be connected to the weight sensor. The green HX, however, has six connections, of which we only need four for the cables.
The connection is as follows:. Apparently there are versions of the sensor. Now you just have to connect the sensor to the Raspberry Pi.
Since this also has only four connections, the wiring is quite simple:. Schematically, the connection to a Raspberry Pi 3 then looks as follows:. If you have an older model. However, you have to adjust the corresponding pins then synonymous in the code. To measure the weight and to read out the value we use a Python library.
How Does a Digital Scale Work?
First, we will clone the project:. It contains an example. Before that, however, a few adjustments are necessary. We are looking for the line in which the reference unit is set and comment it out with a hashtag sign, so that the line looks as follows:. This reference unit is the divisor, but we must first find it out in the next step. The values should appear in the range 0 tobut this is not important at this point. The correct calibration of the weight sensor and the Raspberry Pi balance is crucial.
For this we need a comparison object whose weight we know. For example, I have taken two packs of rice 1kg eachsince it is recommended to choose an average value of the maximum my load cell could be used up to 5 kilograms.In this project, we'll build a weighing scale using a C microcontroller development kit, a load cell, and the Simplicity Studio IDE. The measured weight will be displayed on an LCD screen.
If you include the decimal point and the apostrophe for each digitthis "segment" LCD display becomes a segment display. And when summing all the segments of the eight digits together, we see a total of segments. The load cell that I chose to use is made by Uxcellmodel aux This particular load cell is commonly referred to as a straight bar load cell or a parallel beam load cell. Such load cells are typically available in many rated loads i. And when I say the voltage is "applied to the load cell", the voltage is actually being applied to the Wheatstone bridge strain gauge's excitation leads.
Similarly, it's the Wheatstone strain gauge the produces the output voltage see figure below. For this project I'll be applying 5. And because 5. Side note: Some microcontrollers—not the one used in this project—have differential ADC inputs; single-ended inputs are considered standard for most microcontrollers. When using a microcontroller with a single-ended ADC input and when the sensor in question provides a differential output signal, a differential amplifier must be utilized.
This type of amplifier converts a differential signal into a single-ended signal that can be measured using a standard single-ended ADC. The differential amplifier that I chose to use is actually called an instrumentation amplifieror in-amp. I had no idea that these in-amps cost so much money! Fortunately, this device worked flawlessly. Hence, I think I'll be using in-amp devices from Analog Devices in the future as opposed to TI parts, although generally speaking, I'm a fan of parts, and prices, from TI.
Also, both the TI and the Analog Devices part are advertised as single- or dual-supply devices, and I much prefer to use a single-supply. As mentioned before, the excitation voltage applied to the load cell is 5. Though the microcontroller's ADC has an input range of 0 to 3. Given these conditions, I can calculate the necessary gain for the in-amp, and then choose the appropriate value of the gain resistor R G. R G equation per AN datasheet page 22 :.
Prior to powering up the microcontroller development kit, after all the connections have been made, be sure to configure it as follows:. The load cell itself has holes with, to my surprise, screw threads.Laboratory Weighing. Industrial Scales and Load Cell Systems. Product Inspection. Process Analytics. Analytical Instruments. Automated Reactors and In Situ Analysis. Retail Weighing Scales. Analytical Balances. Precision Balances.
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