TMF882x Distance Sensors

by Danny Staple

Today I’ve come across the TMF882x distance sensor series from AMS. I was exploring SparkFun for some sensors for a project.

I use distance sensors in most of my robots, and my attention has recently been on the VC53LC5X ToF imager. What that sensor does is uses light based time-of-flight to sense distances, but it can sense a grid of distances, behaving like an array of sensors.

The TMF882x series offer a similar capability, with i2c letting a user get distance information. They also have different sized sensor array grids, and come in at a similar price to the VL53 series, perhaps a little cheaper. Their documentation comes with register maps and descriptions, making them friendlier for implementation.

These TMF882x are direct competitors to the ST VL53 series. Which I think is great as competition should lead to innovation in this space.

I tend to buy breakout modules for sensors, so I can directly connect them to a Raspberry Pi, which then makes this easy for students/learners or readers to follow along. They may not have experience designing a PCB, mounting a bare SMD sensor on it, or instructing a PCBA service, so breakout modules allow them access to these sensor to explore the code and i2c aspects of them.

Problems so far

It’s quite early days for these sensors, and I’ve not yet got hold of one.

Availability

I can get TMF8820 modules in the UK, but not the more capable TMF8821 or TMF8828. I’ll keep an eye on their availability. I’ll initially get hold of a TMF8821 module, but my eyes are on the 8828 with an 8 by 8 imaging grid.

Code

Another issue is that since the VL53Lx series have been around longer, there is sample code using them, including Raspberry Pi Python, CircuitPython and MicroPython.

A quick search of GitHub for examples of TMF8820/1/8/x shows a SparkFun Arduino library, but nothing in the Python/Micropython world. Python wrappers to the C interface is a possibility, and I’m sure it’s only a matter of time.

  • Take a look at their data sheet [https://cdn.sparkfun.com/assets/learn_tutorials/2/2/8/9/TMF882X_DataSheet.pdf]. Use the PDF contents menu to navigate. There’s a great register description, and a lot of detail on how to use the sensor.
  • Sparkfun’s Arduino Library for tmf822x
  • Sparkfun’s Open Hardware Design - This is awesome, sparkfun have all their boards and schematics available here too.