That looks like a typo in our guide. The beehive project used a [Particle Photon rather than a Blynk Board. I believe the Photon was connected to the Blynk server though for it’s data collection. I can’t verify this since the beehive isn’t actually in place anymore and the person that created the project is on an extended vacation right now.
The OpenScale communicates via TTL serial so you’d need to connect the OpenScales GND, RX and TX pads to GND TX and RX on the Blynk Board. (or Photon if you’re using that) The rest of the work would be done in software.](Particle Photon (Headers) - WRL-13774 - SparkFun Electronics)
Also, one quick note about connecting the OpenScale to the Blynk board. The Photon has 5V tolerant digital pins so you can get away with connecting the serial header on the OpenScale to the Photon BUT the ESP8266 on the Blynk board runs at 3.3V and is not 5V tolerant so you will need to use a logic-level converter like this [Bi-Directional Logic Level Converter to shift from 5V to 3.3V and vice versa. If you are not familiar with logic levels in electronics, I would recommend reading through [this tutorial.](Logic Levels - SparkFun Learn)](https://www.sparkfun.com/products/12009)
TS-Mark:
Also, one quick note about connecting the OpenScale to the Blynk board. The Photon has 5V tolerant digital pins so you can get away with connecting the serial header on the OpenScale to the Photon BUT the ESP8266 on the Blynk board runs at 3.3V and is not 5V tolerant so you will need to use a logic-level converter like this [Bi-Directional Logic Level Converter to shift from 5V to 3.3V and vice versa. If you are not familiar with logic levels in electronics, I would recommend reading through [this tutorial.
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Hi TS-Mark,
Thanks for your information about voltage.
However I found the Photon also documented as 3.3v:
The Photon does run at 3.3V but the digital I/O pins are 5V tolerant. The table [here lists the ratings for the GPIO and peripheral pins and anything labeled FT, per the note below the table, is 5V tolerant with a few minor issues outlined in that note.](https://docs.particle.io/datasheets/wi-fi/photon-datasheet/#peripherals-and-gpio)