bScale for app.btree.at
Small Arduino Project for a DIY beehive scale, with SIM900 commands to send to webservice. This project is made to work with the webapp app.btree.at, a online database for beekeeper but you can use any webservice you want.
- UNO R3 MEGA (AliExpress ca. € 2.70)
- SIMCON SIM900 Shield (Important with power up pin!) (Ebay China € 21.99)
- atTiny85 + Base (Ebay ca. € 6,00 )
- N-Mosfet (Ebay ca. < € 1,00)
- HX711 Sensor (Ebay China < € 1,00)
- < 200kg platform load cell (AliExpress ca. € 17,00)
- LPDP 5V (Ebay ca. € 1,00)
and battery case, batteries, resistors, jumper wire, scale plattform, Total cost is under € 100,00.
How does / should it work?
UNO will collect data from sensors and send them to the shield. Uno send SIM900 commands. atTiny85 is a simple counter, it will send each 120 minutes a pulse to the N-Mosfet gate. The Mosfet will open circuit to Uno and activate it.
The UNO will tell the atTiny85 when the sending was completed. If the sending is not completed within 60 seconds, the atTiny will shutdown the UNO even it is not completed. (No connection to internet etc.)
For the Sensor reading you need to install the DHT Library and because and bug in Version 1.3 in this library you also need to install the Adafruid Unified Sensor Library.
The made for app.btree.at a web beekeeping software. There the data will be shown in tables and statistics. But you can change the webservice to any you want.
- b.tree Open Source Bienenstockwaage kalibrieren
- b.tree Open Source Bienenstockwaage atTiny85 programmieren
Images (more in img folder!)
SIM900 Power On Pin
Special thanks to
Andi_H from bienenforum.com for the idea and lots of code pieces
bodge awesome HX711.h library https://github.com/bogde/HX711
Nathan Seidle SparkFun Electronics for calibrate code https://github.com/sparkfun/HX711-Load-Cell-Amplifier
My father for help with the electronics.
- 2016-08-30 First field test the battery would handle 10 days. With each 30 minutes open the mosfet for 1 minute. Changed the code to only open the gate each 2 hours and the UNO will tell the atTiny when it is finsihed. Lets see how much of an improvment this will give us. Upload works fine, data also seems ok, Hannes.
- 2016-10-18 Second field test, with the new code (each 2 hours) did the battery last for 50 days. The battery still has power but not enough to open the GSM connection. I will try now instead of alkaline batteries lithium batteries. They should work better with the spike of energy needed for the GSM connection