The final resin cast talisman prototype was included in the parcel. Each item in the parcel has a descriptive note in each zip lock bag.
The included resin prototype had all components mounted inside clear resin to allow sculpturing the talisman shape. The final unit will be milky opaque and not clear.
The included prototype did not have a PCB included so one of the two nuts was loose and has been weakly glued in place. The final talisman will have the nut on the top side of the PCB and will not fall out because the PCB will hold it firmly in place.
The final device will be either bolted onto a custom personalised wrist strap, or will be worn around the neck as a pendant with a chain attacked to the rear of the talisman.
Power is applied to the device with a magnetic clasp once a week to recharge the device.
The talisman will make use of BlueTooth for both communication bridged to the internet and also to detect the proximity of the talisman to beacon units.
To confirm the use of the RSSI (Radio Spectrum Signal Strength) and determine the available accuracy and range a device was built.
The Bluetooth Proximity device has an internal microprocessor, BlueTooth Module and a 2 line LCD.
After starting, each row in the LCD shows the signal strength reading for each of two example beacons. This shows that it is possible to detect when the talisman is within proximity of one or more beacon units.
The beacon units are very simple and contain a low cost bluetooth module that is simply permanently powered via a wall plug pack or other USB power source. There is no requirement for the beacon to contain any microprocessor or to connect to the internet.
To test the proof of concept the two beacon should be plugged into a USB power source, and placed in two rooms around a house. Then the LCD display unit should also be powered via the USB cable and moved around to allow observing the possible detection range and accuracy.
The various tools for developing the firmware were installed on the mac, and a very simple basic program was coded to achieve the simplest test of being able to upload source code onto the device.
The prototype was successfully programmed to simply flash through the colors of the left hand side LED.
The flashing LED shows that the development tool, the compiler, and the programming dongle are working.
An error was found and fixed with two fine copper ‘bodge’ wires. The analog voltage supply and ground was left off. A future revision of the PCB would include these connections and remove the need for the manual addition of the two small fince copper bodge wires.
The fine pitch 32bit microprocessor was placed on the prototype device.
The testing was done to ensure that there were no bridges between the pins.
In the photo a tall bolt is visible. The bolts in the photo will not be present in the end user devices. The bolts are added on the development unit to allow permanent connection of power onto the device. On this development device long extension cables are added to allow the rechargeable battery to be located further from the PCB.
The end user device will not have any of the wires, and the battery will be placed on the top of the two nuts.