Comments on: ESP8266: Turn a $9 Body Scale into a Smart Scale – Part 1

By: dfgdfgdfg

dfgdfgdfg — Mon, 14 May 2018 10:13:59 +0000

Hello,
any news about the scale ? can you publish code for new version of scale that i see on that page with thingspeak and weather support 🙂 ?

By: TMTYB

TMTYB — Mon, 30 Apr 2018 09:56:27 +0000

In reply to Florin. Mine also reset WDT anyone got this resolved?

By: Chip Stewart

Chip Stewart — Sat, 31 Mar 2018 03:39:00 +0000

I just built this and at first it worked great. After I messed around with it for a while (modifying the case, hot-gluing components down, etc.), it’s been acting strangely. First, I saw wildly divergent values. Now, with nothing on the scale and scale.set_scale(), the numbers start out at a few hundred and steadily climb, shortly reaching the hundreds thousands before I pull the plug. I’ve tried another Wemos board, tried another HX711 board, measured the resistance between the white-red-black wires (white-880Ω-red-880Ω-black) on each of the four load cells, checked the continuity between the load cell red wires and corresponding pins on the HX711.

Any idea what might be going on? I’ve got a bunch of mods planned, but need to get this ironed first.

By: Chip Stewart

Chip Stewart — Thu, 29 Mar 2018 21:45:40 +0000

I just built this and it looks and works well. I epoxied a RJ11 jack on the load sensor deck, and again on the box with the ESP, HX711, OLED, etc. This lets me use a standard phone cord and mount the display at whatever height I want.

Then I’ve got a few tweaks:
– I think I’ll add a tar button. I assume I can just activate a “scale.tare();” command using an interrupt.
– I plan on adding buttons for each family member that will send their weight to ThingSpeak – this ought to help lose a little weight. Using your code examples in the weather station kit, I think I can do this.
– Maybe I’ll add a DHT11 – I have a few of these collecting dust.
– I wouldn’t mind having the display show the info from your weather station, when not being used for the scale.
– Maybe eventually I’ll add a body mass index calculator or measurement tool using either height and weight, or electrical resistance.

Any idea, though, how I could make the font larger? I checked the OLEDDisplayFonts.h file and it only goes up to 24pt. It would be nice for the weight to take up the entire height. I’m looking at u8g2 / u8x8, but it looks somewhat confusing. Any ideas?

Thanks for all of your hard work, great ideas, and thorough explanations.

By: Alex

Alex — Wed, 07 Mar 2018 14:30:46 +0000

In reply to Rod.

Damn.. After one hour I just figured it out also (S- and P- are switched)..
This is correct diagram:
https://cdn.instructables.com/FUO/46W0/I0C96FJG/FUO46W0I0C96FJG.LARGE.jpg

And this image is also crucial for reverse engineering (my wires were messed up – black is white, green is black etc.):
https://cdn.sparkfun.com/assets/learn_tutorials/3/8/3/20100816-3wirestraingauge.png

By: Yi Liu

Yi Liu — Tue, 16 Jan 2018 02:51:34 +0000

Fantastic work, Daniel! How about the part 2? Is it still on your to-do list? 🙂 Would love to see all those functions listed at the end of part 1. Best regards, Yi

By: Rod

Rod — Sun, 05 Nov 2017 21:15:31 +0000

It seems your wiring of the load cells is incorrect, or incorrectly labeled in the diagram. (S+ and P+ should be switched)

By: Jotschi

Jotschi — Wed, 27 Sep 2017 21:17:31 +0000

I encountered the same issue and solved it by replacing the yield() calls within the HX711.cpp files with delay(1). In some cases those problems also indicate that the ESP is not getting enough power.

By: Sabueso

Sabueso — Fri, 16 Jun 2017 05:29:19 +0000

the correct diagram to connect the 4 load sensors is in the next link:
http://www.instructables.com/file/FUO46W0I0C96FJG/

By: Florin

Florin — Fri, 19 May 2017 20:45:15 +0000

In reply to boongs. Having the same problem. How did you solve it please