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By JonBDavidson
#199181
Hey all,

I'm brand new to the forum, and I just bought a SparkX SPX-14690 proximity sensor. It's not supported by Sparkfun, and the customer support person couldn't tell me how to hook it up. I know how to hook up the ground and 3.3 V of course, but don't know where the SDA, SCL, and INT pins go, and don't know what they are (other than the Interrupt pin). I don't want to blow the board, can anyone help me figure out how to hook it up to an Arduino Mega? Thanks for any input.
By eeter3000
#199197
That's true that you may fry your board if you try to connect it directly with an Arduino. One runs on 3.3V logic and the other runs on 5V. From the sensors datasheet you can find out that the digital pins are not 5V tolerant. So, you need a bi-directional logic level converter: https://www.sparkfun.com/products/12009

Follow the hookup guide: https://learn.sparkfun.com/tutorials/bi ... okup-guide

Connect your sensors pins SDA and SCL (I2C data and clock) through this converter to Arduino Mega digital pins 20 and 21. These pins should have SDA and SCL markings also on silkscreen. So SCL of your sensor connects to SCL and SDA connects to SDA (through the converter). You may be fine to leave the INT pin open if you don't need interrupts. Otherwise it depends on the library or your source code - it can be connected to any digital input.
By JonBDavidson
#199340
eeter3000 wrote: Sun May 13, 2018 10:00 am That's true that you may fry your board if you try to connect it directly with an Arduino. One runs on 3.3V logic and the other runs on 5V. From the sensors datasheet you can find out that the digital pins are not 5V tolerant. So, you need a bi-directional logic level converter: https://www.sparkfun.com/products/12009

Follow the hookup guide: https://learn.sparkfun.com/tutorials/bi ... okup-guide

Connect your sensors pins SDA and SCL (I2C data and clock) through this converter to Arduino Mega digital pins 20 and 21. These pins should have SDA and SCL markings also on silkscreen. So SCL of your sensor connects to SCL and SDA connects to SDA (through the converter). You may be fine to leave the INT pin open if you don't need interrupts. Otherwise it depends on the library or your source code - it can be connected to any digital input.
That's awesome, thank you! Are you part of Sparkfun tech support, or have you just been around the block with this? I wish Sparkfun's website had been that clear in its directions regarding this sensor, Especially the need for the bi-directional logical level converter.....
By eeter3000
#199352
Glad I could help! Actually I had another problem with a Sparkfun sensor and asked for help. No one replied. Found the solution myself in the end. But I was lurking around and saw your thread. I've used I2C a lot in my professional work, so it was no big deal to leave a helpful reply. The official support is basically non-existent here and some of the guides are incomplete. And I knew it sucks as a beginner when you hit the roadblock and don't know how to proceed. Frying your only sensor sucks even more. You may consider to order in multiples in the future so you have a backup just in case. Or otherwise you have to wait for a replacement to arrive.

With those 3.3V sensors they expect you to buy the Qwiic cables and the Arduino compatible shield. The shield has the same logic level converter circuit on board. It simplifies the assembly but adds some extra cost. If you have a couple of spare wires around, you'll have no need for that fancy connection system. You just have to be aware that some boards are not OK with 5V signals. They should have that warning on their product pages in bold text for the beginners.
By BLH
#199354
Their BlackBoard also has the logic converting circuits. Along with the qwicc connector on it.

There are some Arduno boards like the DUE. That are 3.3 volt modules and can be damaged with 5 volt logic signals and many 5 volt Shields will not work with them.