A newer version with USB interface is here.
Bluetooth Dials is a wireless input device for operating multiple parameters with dials and buttons. We use this device to rotate 3D structures, move them along the x/y/z axes, adjust the contrast and brightness, zoom in/out, move movie frames forward/backward, and so on. It has dials and buttons and sends your operation through its Bluetooth interface or serial connector to your PC. Bluetooth Dials is a wireless version of the historic dial/button box. It's compatible with our RecView and MCTrace softwares. We usually use a mouse with the right hand and this device with the left hand to operate our softwares.
Six knobs are used for changing parameters. Two buttons are used for toggling some functions. The lower button is also used for turning on and off the device. The green LED blinks when the Bluetooth interface is ready, or turns on when the link is established. The red LED indicates the RS232C connection.
The Bluetooth interface of this device is RN42 (Roving Networks / Microchip). For the host-side interface, we use dongles MM-BTUD43 (Sanwa Supply) for Windows PCs. This dongle seems to use a CSR chip. Built-in Bluetooth interfaces of most of our laptop PCs also work well with the device.
The firmware sends dial/button operations to a virtual COM port associated with this device. If the device is paired with your PC, the device port is listed in the Dialbox dialog of RecView and MCTrace. The COM port number can also be found from: Bluetooth icon in the lower right -> show devices -> other options -> COM port tab.
In the default boot, Bluetooth sniffing with a 500 ms interval is enabled (RN42 command: SW,0320) to reduce the battery consumption, but a certain laptop seems not compatible with sniffing. The sniffing is disabled by pressing the lower button while setting batteries.
The original firmware had two modes: serial mode and keyboard mode, though the present release only runs in the serial mode for simplicity. The keyboard mode of the original firmware was enabled by pressing the upper button while setting batteries. In the keyboard mode (though it's not available), the device was recognized as a Bluetooth keyboard. Dial/button operations were treated as if they are keyboard inputs.
There's nothing special. The MCU (PIC16F1828) receives signals from rotary encoders (PEC11R, Bourns) and push buttons (B3F, Omron), and sends those information through the UART TX line to the Bluetooth module (RN42) and to the RS232C interface. The device operates with four AA batteries, or with DC current draw from the RS232C DTR line. The D-sub port can be connected to an RS232C interface of your PC with a stragiht cable, or to a USB port using an RS232C-USB adaptor.
Gerber files are available from the gerber folder.
A few blank circuit boards are available (only for researchers of academic institutions). There is a mistake in the pad connection of RN42 in the available PCB, so it can be used only for RS232C and we do not recommend to use it with RN42 Bluetooth unit. The mistake is corrected in the gerber files above. A newer model with USB interface is here.
The device encodes dial/button operations into ASCII characters Z/X (CCW/CW of the lower left dial), A/S (middle left), Q/W (upper left), C/V (lower right), D/F (middle right), E/R (upper right), G (lower button), and T (upper button) and transmits them through the Bluetooth interface and to the RS232C connector. These character codes can be processed with host-side application. Please find a code example in files DlgDialbox.cpp and MainFrm.cpp of RecView.
In the Bluetooth keyboard mode of the original version, the input characters come through as keyboard inputs, so they can be used as accelerator keys. By associating these characters with target routines, software functions are invoked by the dial/button operations.
Rubber bumpons on the device back are essential. Without these bumpons, the device itself rotates when you rotate knobs. We recommend SJ-5312 bumpons of 3M.
We use connector cables to wire rotary encoders. This is because the encoders often go wrong when we use the device on a daily basis, so we have to replace them on the spot. There would be other workarounds but this seems easiest and cheapest.
