The S928 (also known as the Makibes G01) is a sub-$100 fitness tracker with heart rate monitor. Depending on where you buy it, the S928 can cost anywhere between $60 and $95 shipped.
With that price range, the S928 can be described as a mid-range fitness tracker being a bit more advanced than basic models (that have only pedometer and sleep tracking functions) and less advanced than more expensive trackers such as the Xiaomi Amazfit.
- GPS tracking
- Heart rate monitor (optical sensor technology)
- Pedometer, barometer, altimeter and thermometer functions
- 1 inch monochrome display (128 x 128 pixels)
- Android / iOS compatibility (HPlus Watch app)
- 380mAh battery with 20 hours standby time (2 hours charging time)
- Replaceable silicone straps
- Heart rate alerts (upper and lower limits)
- Sleep monitor
- Sedentary reminder
- Activity modes:
- Smartphone messaging alerts
- Magnetic charging dock
Comfort and Build Quality
Despite having a reasonably affordable price tag, the S928 is actually built quite well and the silicone straps are very comfortable. The straps, available in orange or black, are also replaceable which is another plus point. On your wrist, the S928 doesn’t feel bulky although it looks so.
The buttons are well-placed and have a nice tactile feel and beep when pressed. Overall construction is quite good although care should be taken when using the S928 in wet environments. I have worn it several times when taking a shower and moisture managed to creep into the watch and fog up the display from the inside. With that said, this is not a watch you want to wear for swimming. It can probably withstand light showers and drizzle when running or cycling but nothing more severe than that.
The display quality of the S928’s monochrome screen is quite good. Text and numbers appear sharp enough although I feel that contrast is its weakest aspect. There are 16 levels for contrast and I find that anything less than 16 makes the display hard to read. Viewing angles are fine as long as you set the contrast to 16. In low light, the display has a dedicated button for a backlight that works quite well.
Besides the heart rate sensor and pedometer, the S928 has many other features that cater to adventure and outdoor activities. It has sensors that tell you the air pressure, temperature and altitude you’re at. It also has a sedentary reminder and alerts that can be set for upper and lower target heart rates during exercise. The sedentary reminder works by alerting you when you’re not moving much, like sitting at a desk for hours.
The S928 has several activity tracking modes — pedometer, walking, running, hiking and cycling. Each activity mode is capable of recording data fields relevant to the activity itself. The hiking mode, for instance, shows elapsed time, distance traveled, calories burnt, steps taken and altitude gained. After you’ve completed a hiking trip and save the activity file, you can view these data fields on the watch itself or on the app on your smartphone.
When recording an activity, you’re able to toggle through a 3-set data field screen that shows various details. For example, when cycling the display shows you data fields such as elapsed time, current speed, distance traveled, calories burnt and heart rate.
Although build quality and menu navigation is quite good, the S928 is shipped with a quick user guide that’s written entirely in Chinese which makes it hard to understand what some of the icons in the menu mean if you don’t read Chinese. Even after a few months of using it, I’m still unsure what some of the menu icons mean.
Charging on the S928 is handled by a magnetic docking port which attaches itself to the rear of the watch. It attaches itself securely on the watch and two pins are used to charge the watch. The dock itself is powered by a micro USB cable.
One key feature of the S928 that would attract many is its GPS tracking feature. The S928 uses GPS to accurately show you your current speed and distance traveled. It is also capable of recording GPS tracks and then transferring them to your smartphone via Bluetooth for viewing.
The accuracy of the GPS chip is fairly good and speed readings often come within 1km/h of my Bryton 310 and Android smartphone running Strava. Although the S928’s ability to record GPS tracks seems useful, it is more of a gimmick than it is a feature for serious fitness use. This is because the watch seems capable of recording only up to about 40 minutes to 1 hour of GPS data before it just stops.
This is fine if you’re just exercising for 30 minutes or so but for serious athletes, don’t expect the wealth of data that you can get from apps such as Strava. This issue coupled with the flaws in the accompanying HPlus Watch app makes the GPS feature of the S928 limited in its usefulness. Until today, I still haven’t figured out why the watch doesn’t record GPS tracks beyond a certain duration.
Heart Rate Monitor
Like all other sub-$100 fitness trackers with heart rate monitors, the S928 does not display your heart rate in real time. By “real time” I mean the refresh time for each heart rate reading is around 2 to 3 seconds. The S928 refresh rate is about several minutes.
Users who want real time heart rate readings will be better off using heart rate monitors that measure your HR using ECG belts which give refresh rates of 2 to 3 seconds. Some product pages of sub-$100 fitness trackers that are worn on the wrist actually claim to have heart rate sensors that use ECG to measure but this is not true and is misleading.
ECG stands for Electrocardiogram and is a method of measuring heart rate using highly sensitive electrodes that are placed on the chest area. Sport gadgets that track heart rate typically come with ECG belts that transmit HR readings via Bluetooth or ANT+.
Fitness trackers that are worn on the wrist are not capable of picking up the faint electrical pulses generated by the heart. Instead, they make use of highly sensitive optical sensors that detect changes in the skin tone or color. When your heart contracts to pump blood throughout your body, a higher volume of blood flows through the capillaries underneath the skin thus changing the skin tone slightly. Although not obvious to the naked eye, these changes can be detected by optical sensors on fitness trackers.
ECG belts are generally more accurate than optical sensors worn on wrists. There are pros and cons to both methods of measuring heart rate (ECG and optical sensor) but I will not discuss them in this review since it will be quite lengthy.
The S928 does a decent job at measuring your heart rate as long as it is worn snugly on your wrist. If it’s not snug enough, the small gap in between the sensor and your skin may result in inaccurate readings or no readings at all.
Since the S928 displays heart rate at intervals of several minutes, it is not suitable for serious athletes looking for a device to track their HR in real time. It is, however, good enough for users who want to track their overall heart rate throughout the day or are just curious to know how hard they’re exercising.
For users with heart problems who are looking for an HR monitor that can help them exercise within a safe HR range, I wouldn’t recommend the S928. For such users, getting an ECG belt is the better option. This is because it is possible to dangerously strain the cardiovascular system within just 1 or 2 minutes with very high intensity exercises. By the time the S928 warns you that you are way above your target HR zone, you may have already been in that zone for a minute or two which can cause serious issues if you have a weak or vulnerable heart.
The S928 works with the HPlus Watch app which is the recommended app for this watch although I read that it is also compatible with some other generic apps that can connect to some fitness trackers via Bluetooth. The HPlus app allows you to see how many steps you’ve taken, your heart rate and your sleep records in graphical charts and graphs. It also allows you to control features on the S928 like setting it to receive alerts from Facebook and messaging apps.
You can also view your activity or exercise files using the app. However, this feature is somewhat disappointing since the GPS tracks recorded by the watch is pretty much useless if you’re living outside China. This is because the app can only display the map of China. If you did your activity somewhere else, all you’ll see is your GPS track and a blank map.
In fact, there are so many flaws in this app that the average user rating for it in Google Play is close to 1 star. The S928 has some pretty decent hardware and performance so it’s quite sad to see the accompanying app being a big disappointment. For now, S928 users can only hope for the app developers to improve on the app and make it better.