Tag: hardware

New CPU – Dual Core Confirmed

A brief post to confirm that Talisman V2 will no longer require a seperate CPU, but will use the CPU that comes on the needed (WiFi and Bluetooth) radio module.

Earlier consideration had been given to the single core ESP-07, but this was upgraded to the more powerful dual core ESP-WROOM-32.

esp-wroom-32

The above image shows the WiFi radio module – left hand is the top side view, right side is the rear view. It is 1 inch in height and thin.

This CPU also has more pins which makes it easier to wire connections to all the other components.

 

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New Dual Core CPU Up and Running

The new central processing unit (CPU) that will power the Talisman V2 is up and running! Yeah, whoop, whoop. This is significant because it implies / proves that ‘we have the technology’ (sorted) to wire up power to the chip, communicate to it in order to load an initial trivial program.

So it is now possible (for me) to use the new dual core CPU. With this first most basic of programs working, it is possible to move on with success adding more interesting programs.

In short, the rest of the firmware on the Talisman is just more of the same of this first program, whereas getting the first program required all the configuration, code editor program setup, coding language , compiler and other geekery.

First Light

This image shows a hand wired prototype that is used to confirm all electronic components. Of most interest is the right hand side white square with the two red push buttons. On this white square the WiFi radio module (with dual core CPU) can be seen within the right hand side white area. It is the metal covered square with the tall black square on it’s left.  Actual size 1 inch wide.

In the centre of this photo is another smaller white square with a single core, slower less powerful WiFi module. This is not being used, since the more powerful dual core module is now working.

The other component of note is the new upgraded power regulator, also wired up and working to power the circuit. This can be seen on the small green square board with the two tan circular ‘lentil’ looking components towards the top row of the photo. The actual power regulator is the tiny small black rectangle in the middle of the green square.

The remaining components have all been wired up and used successfully on the previous V1 Talisman. The next task is to programming the new WiFi radio module with the dual core CPUs to communicate to the previously used components. (vibration motor, accelerometer, LEDs, battery charger.)  Once this component confirmation is completed, the components can be arranged to fit on a printed circuit board with their tested wiring.

 

More (Smart) LEDs

The Talisman V2 is using the CPU already included in the WiFi radio.  This Wifi CPU has less control wires made available than what was available from the independent CPU controller in Talisman V1.

In Talisman V1 there were 3 full color LEDs. Each full color LED used 3 wires – one wire for each of the red, green and blue LEDs. Therefore the Talisman V1 had used 9 control wires. (3 sets of 3 wires.)

Smart LEDs are being used in Talisman V2 to reduce the number of control wires. A large number of smart LED can all be controlled from one single control wire.

(This is achieved by sending the necessary color data for all the RGB LEDs over the single wire into the first LED. The first led then daisy chains the data passed along to the next LED in the sequence.)

The image above shows a V1 Talisman LED that with 3 wires on the left. On the right animated image is single smart LED. It can be seen in the right hand side photo that the little 5mm square LED has a dark chip rectangle and tiny gold wires within the white package. Each smart LED in V2 comes with a little chip inbuilt!

So, this posts shares how it is possible to reduce the number of data control wire by the use of smart LEDs from 9 to 1.  In addition it is possible to daisy chain a very large number of smart LEDs in a long sequence.

It is intended to add additional full color LEDs onto the Talisman V2, most likely in a circular ring or oval layout. This should allow the Talisman V2 to be orientated anyway an artists chooses. The Talisman V1 only had LEDs on the front edge, so V1 had to be orientated a certain way when artistically mounting.

Prototyping the smartLEDs today, uncovered a downside; they use power even when no light is being emitted! In fact their little internal chip uses so much power even when dark that they would over time significantly reduce the battery life.   For this reason it is necessary for the Talisman V2 to switch power off for the LEDs unless they are going to be shining.

It so happens that there is already a spare switched power available on the Talisman V2. The Talisman V1 used to have a Bluetooth controller that had it’s power turned on and off. This bluetooth is no longer required, so the second switched power is now used for powering on and off all the smart LEDs on V2.

Version 2 – Upgraded CPU with WiFi

Initial feedback on the Talisman V1 confirmed the requirement to minimise size and simplify the usage.

If the Talisman were able to connect directly to WiFi this would simply the deployment because the use of a bridge would no longer be necessary.

ESP-07

A search of the available radio modules resulted in the selection of an extremely low cost WiFi module from ExpressIf in China. The ESP-07 WiFi module provides WiFi ability. The module can connect to an existing internet WiFi network as a client. This network would be a user’s home WiFi network, or a WiFi network shared from the users roving mobile handset. Most mobile devices can act as a AccessPoint, sharing their cellular mobile internet access on a password protected WiFi network. This is simple to use and just requires turning on on a mobile device.

The ESP-07 also can act as an Access Point. This is useful because it allows the module to provide a WiFi network that the user can connect to. A user could connect to the module in the Talisman V2 using their laptop or mobile phone. The user would simply select the Talisman V2 provided WiFi network from the list of available networks on their mobile or laptop.

Once a user connected to the Talisman V2 they could browse to a Talisman V2 provided web page and enter the details of their home network.

Having the Talisman V2 provide a WiFi network with a single simple web page for entering network name(s) and password(s) allows the user to configure the Talisman to use their password protected home WiFi network.

The ESP-07 WiFi module can obtain the RSSI signal strength of nearby WiFi networks. This will be used to detect the close physical proximity of the Talisman V2 to beacons.

The ESP-07 also provides access to store data and downloaded apps. The ESP-07 can be programmed to run the apps. Therefore using the ESP-07 would no longer require a seperate micro-controller. This reduces the number of components, and allows the design to be shrunk in size.

Given that the ESP-07 radio module provides WiFi and can use RSSI to detect nearby beacons, the Bluetooth module can be dropped from the hardware design.

It is proposed that the Talisman V2 would use the ESP-07 WiFi module and no longer require or support the use of bluetooth.

All the features mentioned above are being tested to ensure the functionality works as expected. A more comprehensive post will be made showing this version 2 parts prototype.

Potential Hardware Bridge module

In the Transport Layer document, the requirement for a dedicated hardware Bridge was discussed.

MH-ET-LIVE-ESP32-Development-Board-WiFi-Bluetooth-Ultra-Low-Power-Consumption-Dual-Core-ESP-32

This device would require locating some sort of WiFi module to connect to the internet, and a Bluetooth 2.0 radio to communicate with the Talisman radio.

Above is a photo of a hardware module that does everything required, readily available at low cost, and easily programmed to act as a relay bridge.

This ready assembled module includes a WiFi module, a microprocessor to control the basic relay of the messages, and a Bluetooth radio. It is to be confirmed that the Bluetooth Radio is compatible with the 2.0 and BLE versions, which means this unit could support current Bluetooth 2.0, and also any future Bluetooth BLE iPhone radios.

The unit is available already assembled, and can be powered by simply plugging any readily available phone charger cord into the USB charge type socket on the module. The socket to plug the USB power cord is seen on the right of the unit half way along the short side. The socket accepts the standard slim USB cable used for Samsung phones etc, and appears in top down view as a silvery rectangle in the photo (between the EN and BOOT white lettering).

The unit could be very cheaply enclosed in black shrink plastic. There is no requirement to solder anything onto the unit. One end with the power USB socket would remain visible.

A sample of this device is being shipped to Allan, and if it is as listed would immediately fulfil all the current (and future) requirements of a dedicated Hardware Bridge.

This is excellent because it could remove the need to design our own Hardware Bridge circuit board, remove the need to source components and locate an assembly factory.

The unit can be obtained in single units, or hundreds of units from China from multiple suppliers under $8 USD per unit, delivered. The unit would require the program that would relay the data to be loaded into each unit using a cable. This is a simple plug the cable and click a program button operation that does not necessarily require an electronics person with soldering skills.

The end user would bring their home WiFi network name and password to the induction event. They would then be guided through a very very simple process where they enter these two pieces of information into their Hardware Bridge. This could be done very simply by browsing to the Hardware Device using any mobile phone and entering the network SID and password into two fields on a simple web page.

The settings for their home WiFi network would then be stored on their device.  Once home, the user would find a spare wall plug pack used for charging a cell phone, plug the cable into the Hardware Bridge, and place the unit somewhere in their house out of the way.  They would not have to do any else.

(Allan also ordered a range of Bluetooth BLE modules to allow testing what hardware would be required to support iPhone bridge. Any iPhone Bridge would require a redesign of the Talisman PCB to accomodate a different iOS capable Bluetooth BLE (not the existing Bluetooth 2.0) module.  A selection of various available Bluetooth BLE modules from each of the major Chinese manufacturers was ordered.)

Status – Hardware and Firmware

The table below lists the current status of the hardware functional tasks and (when required) the corresponding firmware driver source code.

Function Hardware Firmware
Reverse protection for magnetic connector Tested not req.
Lithium-ion battery charging Tested todo
Battery level sensing Tested todo
Voltage regulation Tested not req.
In circuit device programming (dev only) Tested not req.
Microprocessor high speed operation Tested todo
Microprocessor sleep mode operation todo todo
Inbuilt flash storage reading todo todo
Inbuilt flash storage clearing and writing todo todo
Three full color LEDs 1 of 3 done todo
Bluetooth serial data link (master mode) todo todo
Bluetooth RSSI proximity measurement todo todo
Vibration motor todo todo
Accelerometer XYZ sensing todo todo
Accelerometer single tap detection todo todo
Accelerometer double tap detection todo todo
Bluetooth beacon with plug pack todo not req.
USB cable with BT and Win7 bridge program todo todo
Android Bluetooth bridge app todo todo

The not req. indicates that driver source code is not required for the particular functional area.