Develop a tail cuff small enough to fit the mouse that can be securely fastened to its tail. This tail cuff should be similar to the inflatable blood pressure cuff used on humans, scaled down to a smaller size appropriate for mice. The mouse will most likely be conscious, so position the device in such a way that the mouse cannot chew or damage it.
Attach a photoelectric sensor to the cuff. The sensor should be capable of being hooked up to a computer with relevant software, such as LabChart, to capture the data. Photoelectric sensors, used in conjunction with a blood flow blocking cuff, detect changes in the transparency of the skin area in contact with the sensor, providing a close approximation of systolic blood pressure.
Secure the device to the mouse in the appropriate environment for your particular experiment.