Matt
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Alessandro, Your first two questions are correct. If the battery is fully charged, the charger will not pull the status pin low. On the third question, you will not get an event if the battery is fully charged. If you need to specifically kno…
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Hi rezaii24, RG/RPro firmware has now been shipped, and we have an early internal release firmware with SPI functionality that we are testing out. Mobile APIs would still need to be updated and shipped. What is your hard deadline and which pl…
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Hi Alessandro, Unfortunately, due to limited board real estate the Vusb signal is not connected to the SoC. You could use a voltage divider to drop the voltage down to 3V and connect it to a GPIO input. The battery charger IC will prevent backfl…
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In response to your last comment, yes, you can effectively ignore the delays when using the logger as your time base. All data points coming from the accelerometer will be affected by roughly equivalent delays before hitting the logger. You are me…
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Lets first roughly estimate the time resolution you need to distinguish 1cm differences at 3m. The equations above work well for an estimate. First the time it takes to travel 3m in freefall. d = A/2 * t * t t = sqrt(d / [A/2]) t = sqrt(3m …
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It should also be noted, that the way the interrupt triggers -- there is a freefall debounce period before it activates -- will cause you to always measure less than the actual time. That is, the error will always add more time to the fall or dista…
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Jon, What will underpin the accuracy for this use case is the time resolution of the free fall detector in the accelerometer. The timing will be used to determine how long the object is falling, which can be used to calculate the distance travele…
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Hi Jon, there are a couple of delays in the system from stationary to motion, or motion to freefall. First, if you are using the accelerometer "Auto Sleep" power saving mode, there may be a several sample delay for the device to wake up when it se…
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Hi admford, the buzzer is connected with 30 AWG wire, and the battery with 24 or 26 AWG wire. Even 28 AWG would be fine for the battery because it only needs to handle 100mA of current.
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Derek, with the present MetaWear firmware release you can store around 15000 entries in the log. Storing X, Y, and Z will require two entries so you can only store half that many accelerometer data points. The logger shares flash memory with the f…
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Hi @igor_filippov, @erwin, @erwin, you are correct, MetaWear is digitizing using a 10-bit ADC. It should not be possible under any circumstances for the API to report 4V on an ADC input, so we must have an issue somewhere. Could you post a sh…
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Hi Eric, Thank you for your feedback regarding the MetaWear protocol. There are several constraints underpinning our decision to tunnel through GATT instead of building on top of it. The gist is that it cannot handle an implementation with th…
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We will give some thought to how an ADC calibration feature might work in the FW. A static offset cannot easily be applied to a supply relative measurement, due to the varying supply voltage. With the data processing module, it is now possible to …
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Hi patrikdj, The MetaWear firmware is always set to use the 10-bit mode. You are correct about the number of bits and how that affects the resolution, except that 3V/1024 would be 3mV per step. In terms of absolute accuracy, it will be sub…
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Hi Edumana, You can use any 3rd party rechargeable lithium type battery. However, the MetaWear board is setup to charge at 90mA, so it may take a long time to charge batteries larger than 300mAh. At volume, MetaWear can be configured for up to 3…