ErgoDox Wireless FAQ
How long is the battery life on a 400mAh battery?
Without solar charging and without a dongle, the left half (central half) will last around a month and the right half (peripheral half) will last around a year. Without solar charging and with a dongle, both halves will act as a "peripheral" half and the battery will last around year. Please read about how a dongle improves battery life for a split keyboard.
With solar charging and a dongle, the battery life will be dependent on the amount of light available. Solar charging does not need to be in direct sunlight but does need natural (rather than artificial) lighting. It will automatically charge when there is enough light and use the battery otherwise. Having the keyboard somewhere in the vicinity of a window should be more or less enough to maintain the battery level.
Without a dongle, solar charging will not improve the battery life for the left/central half. The right/peripheral half will be able to benefit fully from solar charging.
Are there wireless signal issues with the aluminum case compared with the layered acrylic case?
We haven't seen a significant difference in the signal quality between the aluminum case and the layered acrylic case. In particular, the aluminum case has an acrylic bottom layer to ensure that the signal can propagate.
In our experience, the number of disconnects due to interference is about the same with the two options. Over the last few weeks, our logs recorded on average a few disconnects each week. These disconnects often don't even impact usage as they may happen when the keyboard is not in use and the connection will be automatically reestablished. It merely serves a useful measure for comparing the two cases.
In terms of distance, the aluminum case worked fine up to around 4 meters. While most won't use the keyboard from that far, being able to do so suggests that there won't be signal issues at a more "typical" range.
Our testing was also conducted with 4dBm signal strength rather than the 8dBm maximum. There is also a Bluetooth Coded PHY feature that can be enabled to allow the signal to travel a greater distance at the cost of greater power consumption. We didn't test with these measures in place as they weren't necessary for the aluminum case to be functional.
How is the wireless latency?
ZMK currently supports Bluetooth connection interval as low as 7.5ms, which means median latency can be as little as 3.75ms. In real world scenarios with a dongle, the median latency will be somewhere around 5ms-10ms to account for USB latency, key press debouncing, and general firmware logic processing. A device connected wireless to the dongle will experience an additional couple of milliseconds as data has to travel wirelessly twice.
It's difficult to quantify the latency objectively because there are so many factors that influence it. Configurable options such as the connection interval and the key debouncing period can decrease latency at the cost of using more power.
Theoretically the hardware can achieve wireless latency can be as little as 3ms with a dongle. The Nordic microprocessors that we use supports a Bluetooth extension called Low Latency Packet Mode, which allows the connection interval to be as low as 1ms. Combined with 1ms of USB polling and 1ms of processing time gives around 3ms. While this is something that can be activated via a firmware upgrade, please note that there is no concrete plans to use Low Latency Packet Mode at this time.
Can I use the keyboard with multiple devices?
Yes. If using a dongle, one computer can use the dongle as a USB keyboard and additional devices can connect to the dongle wirelessly.
If not using a dongle, multiple devices can connect to the central half wirelessly. The central half can also be plugged in via USB and used directly as a USB keyboard.
Can I use the keyboard in a wired manner?
If using a dongle, only wireless is supported for the connection between the keyboard halves and the dongle. In such case, the USB connection for the keyboard halves is solely for the purpose of charging. The dongle behaves as a USB keyboard and can be used on devices without Bluetooth.
If using one of the keyboard halves (such as the left half) is used as the central in place of an external dongle, that half can be used directly over USB as a USB keyboard.