New Hardware + Control Capabilities Unlocked With Accelerometer

Thanks to everyone's support, we've hit our first stretch goal which adds an accelerometer sensor to the PolyCast5 multi-tool remote for additional control. Let's check out the new hardware and what cool new capabilities this adds!

Let's start with the fun part. What does this mean for controlling stuff?

Basically, you can now use your PolyCast5 like a literal steering wheel! You can also use it as a wearable for hand gestures, or really anything else tilt-related you can think of.

(Could secure with a small strap or 3D print.)

Let's check out how it works!

First we can check out the new sensor. The accelerometer that ended up being chosen was the LIS2DH12 since it supports I2C only mode (PolyCast5 has no extra pins but it's free with the I2C bus) and it has a super low power consumption of only 11 μA. Basically zero compared to all the built-in radios.

Figured it would be neat to put it close to the battery connector since it also has a built-in temperature sensor. This said, we get the bonus of battery temp + tilt!

As far as the accelerometer schematic goes, it's honestly pretty basic: only requiring a couple of decoupling capacitors.

If you're curious how I knew this, check out the datasheet. You may notice I did some questionable things such as tying the CS pin and SDO high, but this is just to select I2C mode since the chip supports I2C and SPI. 

As I mentioned earlier, I2C is required here since PolyCast5 has literally no extra GPIO pins but did already use I2C for a GPIO expander. This means I can simply add the LIS2DH12 to the bus without needing any more pins. Perfect!

While waiting for the new PCBs, there was an opportunity to start updating the PolyCast5 firmware. However, this is hard to do without actually having the new sensor on the board. Perfect application for the broken-out GPIO pins!

This is just a basic LIS2DH12 development board on Amazon which was then soldered to some PolyCast5 protoboard.

Now you can plug it into the external GPIO pins and it is the functional equivalent of just adding onto the I2C bus.

Of course, you can also do this for other sensors! Mostly everything will have I2C compatibility. But even if something doesn't, you can use I2C to communicate with another microcontroller which could then use any communication protocol.

The next hardware stretch goal for PolyCast5 is a magnetometer which takes this concept to the next level by adding the last dimension.

Currently PolyCast5 can measure pitch and roll with the accelerometer, but with a magnetometer we can also measure yaw! Illustration below:

You'll be able to do a lot of cool things with this like controlling an RC car using the current accelerometer as the throttle then handling orientation with the magnetometer. Of course, there is a lot of other awesome stuff you can do with this too. Since it uses ESP-NOW on Arduino IDE, this can be applied to literally anything!

There will be a separate tutorial on this out soon so you can dive in whenever your PolyCast5 arrives. If you don't have a PolyCast5 multi-tool remote but are interested, check out the homepage and the Kickstarter.

Happy casting!