What you will need
The components I used in my project set me back between USD $30-40 including the body scale. The following list should give you an idea what components you’ll need and what you should be looking for.
| Image | Description | Costs | Where to buy |
|---|---|---|---|
|
Original Digital Body Scale |
Digital Body Scale: It is very practical if you can build your smart scale project on an existing digital scale. From what I can tell modern digital scales all use the same kind of sensor (load cell) but I cannot guarantee it | ~$USD 10.- | Switzerland: Coop. IKEA also has a low-cost scale: IKEA |
|
Wemos D1 Mini |
The ESP8266 module is the next important component. It is the brain and mouth of your smart scale. I recommend a small development module like the Wemos D1 Mini: it has enough pins and is small | USD $6.50 | Squix Shop |
|
HX711 Amplifier Module |
The HX711 module is a so called Load Cell Amplifier and will convert the weak analog signal from the weight sensor into bits and bytes the ESP8266 can understand. | USD $3.00 | Squix Shop |
|
LifePo4Batteries |
Power Source – I picked a Lifepo4 AA-type battery since it provides the perfect voltage and has a considerable amount of capacity. The AA packaging (14500) also helps to buy or 3d print a good holder. If you don’t own a 3d printer also buy a AA-cell holder | ~USD $10.- | AliExpress |
|
SSD1306 0.96″ OLED display |
These OLED displays are just wonderful: since the pixels glow by themselves the contrast is very high. You can choose between the 0.96 inch SSD1306 display or the 1.3 inch SH1106 one. The smaller one you can buy in the Squix Shop, the other you’ll have to order from AliExpress or similar | ~USD $6-7.- | 0.96″ from Squix Shop |
Besides these “core” components you will also require wires, solder and solder iron, screw drivers.
Summary and Outlook
This was part 1 of the SmartScale write-up which explained you the hardware setup. After working through this article you now have hopefully a working but still pretty dumb body scale.
A few features that the SmartScale will have:
- Over-the-Air Update: Just turn on the body scale in the bathroom and deploy a new version of the software
- Blynk App Integration: see wonderful historical statistics and live data on your smart phone
- Change between Kilograms and Pounds through the Blynk App
- Energy saving mode: turn off the HX711 and the NodeMCU after 5min of inactivity. This will not be perfect but better than burning through the battery as quickly as possible;-)
- Displaying the Weather Forecast, so that you know which clothes to pick after the shower
- Do simple settings by using the load cell as input device
Over-The-Air Update
Live and historical data on your Smartphone by using Blynk
Weather ForeCast download from the internet
Choose the user by carefully applying the correct weight on the scale
[tps_footer][/tps_footer]
