Wearables are hot these days, and PNI Sensor sees a good fit in that space for their SENtral chip. They’ve bundled it into what they call their SENtrode, together with appropriate algorithms.
They’re even working their own heart-rate monitoring algorithms – evidently a particularly difficult task when you’re in motion (which you are likely to be with a wearable). Good heart-rate monitors have proven challenging to create – unless you go with the golden reference of a chest strap, which isn’t exactly comfortable or convenient. They’re hoping to crack that nut with their own approach.
While there’s focus on wearables, they actually launched two versions: one in a bracelet-sized form factor (the wearable one), and then one optimized and housed in a fashion more appropriate to internet-of-things (IoT) gadgets. (Although, realistically, wearables are part of the IoT – or perhaps the Internet of Clothing and Accessories…)
The features differ somewhat between the two versions. The IoT one swaps humidity sensing for the heart-rate monitor. The algorithms swap barometric pressure and humidity for altitude and motion-compensated heart rate.
Of course, there’s one parameter that tends to trump all others, particularly in a wearable: power. The SENtrode solution runs at about 380 µW. Honestly, it’s a bit hard to compare, however, since numbers don’t tell the whole story. For example, Quicklogic’s numbers may come in lower, but PNI says that they don’t have a floating point unit and that their algorithms are less sophisticated.
Makes me wonder whether we need some serious work on sensor power benchmarking… EEMBC perhaps?
This is a development kit; they’re releasing the software, the schematics, the whole shebang. It’s also modular so that parts can be swapped out. It’s expected that a developer will be optimizing hardware for a specific application.
You can find more detail in their release.
(Images courtesy PNI Sensor.)
