Advisory: Smart bathroom scales from 20 euros

April 12, 2020

Networked scales are now available for less than 20 euros. We show what to look for, how to protect the data and what values ​​are important.

With the resolutions for the new year, “losing weight” almost always makes it into the top 10. No wonder, too high a weight can lead to numerous problems such as diabetes, depression or joint damage. No matter if you tackle the pounds with running, general fitness or interval fasting, somehow you have to monitoring the weight. It's good that there are now networked scales that deliver the data directly in apps on the smartphone. The difference between networked and stupid scales is a few euros. This has the great advantage of being able to track your weight and recognize trend curves. This is additional motivation. Don't worry, you can do this without sending your own data to any clouds – despite cheap Asian manufacturers.

We have collected more information about smart scales in our themed world of scales. There are, for example, individual tests for devices such as the Garmin Index (Review report, rating 3), the Xiaomi Mi Scale or the Withings Body +. If you are in a hurry, you can jump straight to the comparison of six smart scales.

Crash course: BMI, body fat and accuracy

In addition to the weight, the smart scales provide other values. This includes the Body Mass Index (BMI) and often a measurement of body fat. What sounds great at first should be taken up with a little skepticism. The BMI is used everywhere as a benchmark, but it is anything but controversial. Experts complain that the value is too simple. The BMI results from the weight divided by the body size squared. From a value of 25 you are considered overweight, over 30 you are obese. That would apply to actor Dwayne "The Rock" Johnson, who has a BMI of 34.3 according to the website Supernifty. This already shows that the calculation, which was developed in 1890, actually contains too few variables. The BMI also ignores data such as bone density or muscle mass.

Measurement number 2 is body fat. The scales use the bioimpedance method for this. Metal plates on the scale send a weak, imperceptible current pulse through the body. Fat conducts electricity less well than muscle tissue and the difference can be used to calculate the percentage of fat. The problem: If the sensors are only on the feet, the values ​​are inaccurate. A full bladder can lead to significant deviations. It is better if additional sensors are attached to the body. This is the case with very few scales. A positive exception is the Phicomm Smart Scale S7 (Review report, grade 1).

So how should you handle the data? We recommend keeping calm and evaluating the information such as the sleep data of the fitness tracker. They show at most a long-term trend, less the minute-by-minute fitness. Measurement by a (sports) doctor provides better values.

Bluetooth or WiFi

Most scales use Bluetooth to transfer the data to the smartphone apps. Others also use WLAN exclusively or exclusively, devices like the Withings Body + use both. Both techniques have advantages and disadvantages.

With Bluetooth, the cell phone must be within range of the scale so that the data can be transferred. You usually do not need an account with the manufacturer and can use open source alternatives instead of the manufacturer apps.

WLAN devices, on the other hand, do not need a smartphone, but an account in the cloud of a fitness provider is almost mandatory. The advantage is that the data can be processed together with the information from training or fitness trackers.

Data protection thanks to OpenScale

If you want to remain the master of your medical data, you don't have to do without cheap smart scales. Because thanks to the Android app OpenScale all data remains on the smartphone, manufacturer apps or clouds can be safely ignored.

OpenScale it doesn't have to hide from other fitness apps, on the contrary. Assuming a compatible scale, the app can read and process data on weight, BMI, water content, muscle mass, body fat, basic metabolism and total energy metabolism. Additional measurements, such as the waist circumference and thus the waist-to-size ratio, can be activated optionally. There is also a smart recognition of users and the possibility to set weight goals.

OpenScale can be obtained free of charge via the Download Marketplace Fdroid. The app is alternatively available in the Google Play Store, once as a free lite version and once as a 2.99 euro pro version. The latter is needed to add new scales with the Google Play app, and it also supports development.

For the article we have OpenScale tested with the Anjou AJ-PHA004 scale. This could be easily smart health connected to the app and provided all the relevant data, although it is not officially supported. It can be assumed that many manufacturers simply use the same components under their own names. Other compatible devices are the Xiaomi Mi Scale V1 and V2, the Sanitas SBF 70, several scales from Beurer or Medisana. The complete list is available on the project's github page.

Incidentally, the measured data does not have to be in OpenScale stay. If you want, you can export them as CSV or via the app OpenScale Compare sync with Google Fit.

Scales with connection

If the scales should not stand alone, we recommend using a device that is compatible with your own sports watch (theme world), fitness tracker (theme world) or sports watch (theme world). Scales such as the Fitbit Aria 2 (Review report, rating 2) or the Garmin Index (Review report, rating 3) recognize the user and deliver the data directly to the appropriate app.

Depending on the application, they are combined with the fitness data that a fitness tracker provides. Unfortunately, the manufacturers rarely make more of the information, they hardly flow into training proposals. However, you can, for example, set goals, the achievement of which then unlocks success.

Conclusion

Our tip: If you are looking for a cheap scale with smart measurements, you should definitely choose one with OpenScale is working. Even in the paid Pro version, the app offers excellent value for money and can do things that many manufacturer apps cannot keep up with. In addition, you yourself remain in control of your data – and can still use the cheap products.

We currently still miss the added value of scales from manufacturers of fitness hardware. One advantage, however, is that Fitbit, Garmin and Co present all relevant health information under one surface.

For us, a sensible digital scale is an important part of the fitness arsenal. They now cost no more than a simple bathroom scale and it is always motivating to be able to follow your own weight curve. Yes, this can also be done with an Excel spreadsheet or a notebook – but it's much more practical in the app (and you “don't forget” any values).

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