![]() ![]() The correct calibration of the weight sensor and the Raspberry Pi balance is crucial. The values should appear in the range 0 to 200, but this is not important at this point. Meanwhile you can run the example (abort with CTRL+C). This reference unit is the divisor, but we must first find it out in the next step. Save it with CTRL+O and exit with CTRL+X. 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: ![]() Before that, however, a few adjustments are necessary. It contains an example.py file which shows the function of the library and can also be used. First, we will clone the project: git clone Although there are corresponding C ++ libraries, however, I have no good experience with that. To measure the weight and to read out the value we use a Python library. However, you have to adjust the corresponding pins then synonymous in the code. Of course, you can also change the pin assignments of DT and SCK, e.g. Schematically, the connection to a Raspberry Pi 3 then looks as follows: Since this also has only four connections, the wiring is quite simple: Now you just have to connect the sensor to the Raspberry Pi. Where the pins are labeled S+/S- instead of A+/A. Apparently there are versions of the sensor. The green HX711, however, has six connections, of which we only need four for the cables. The four cables of the Load Cell must be connected to the weight sensor. If the construction is complete, we can go to the HX711. Side view of the scale after both boards are mounted. The nuts should be well tightened so that the screws do not slip off the board. ![]() Attach the underside of the balance first. Between the screw and the load cell, there should be a nut, which serves as a protection to the board (see pictures). With a drill I drilled the holes and inserted the screws. For this I made markings with a ballpoint pen on the wooden boards, where the screws come in. If someone has screwed his scale and both are present, I would be pleased about a comment with name / manufacturer of the balance.īefore the load cell is connected to the HX711 weight sensor, it should be mounted on the two plates. Since complete scales cost only slightly more than the load cells, this is definitely worth considering. In any cases, a load cell is available and sometimes also a HX711 weighting sensor. Two boards (the boards should not bend easily, therefore the best is not too thin plywood)Īlternatively, you can also take an existing person or kitchen scale and unscrew it.The pressure sensors probably have small differences, but are – theoretically – both compatible. This sensor is available in two versions: red and green. To read out the values, the HX711 weight sensor is also required. Even though some have a different form, all are provided with four cables. This is available for different weight classes (up to 1kg, up to 5kg, up to 50kg, etc.). The most important thing to build your own scale is a “load cell”, which is a metal bar with a hole in the center (see picture on the right). ![]() Of course, it is also possible to unscrew an existing (person) scale and read it out using a Raspberry Pi. In this tutorial we are building a simple Raspberry Pi kitchen scale, whose precision is amazingly accurate. Only a sensor and a load cell are required, which are available for different weight ranges. This can be used in various applications as the weight value ranges which can be measured are also almost unlimited. As hardly any scales work analogously, it is of course also possible to measure weights with a digital Raspberry Pi scale. ![]()
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