[ScorpiusWireless]

Here it is. 
The SCX Solenoid driver and pins has been replaced by a Digital to Analogue Converter chip or DAC.
Our OLED driver connects to a 0.49" OLED screen to select channels.
We have utilised the two Photo Transistor analogue input pins to connect a set switch.
As usual the MPD is used as the mother board.
The board is powered off the 5V supply from the CU.
The DAC chip connects to the CU via the RJ12 telephone plug.
The Scorpius Controller to MPD data is complete.
And work is underway in the next few weeks to implement Carrera Controller protocols to the CU.
So as you can see the MPD really is a Multi Protocol Decoder capable of almost anything. 
In fact the Controller, USB Dongle and MPD can do every single function required for any brand. Very cool indeed.
The MPD boasts digital in/outs and now Analogue in/outs. 
Along with the TX/RX in/outs added and the OLED driver this is going to be a killer product.
And all this in 22.00x13.3mm.
Thankyou Johnny you are a legend!

   

Rick

[ScorpiusWireless]

The CU can also take  PWM data via ports and it’s also an option. Just trying to work out the most practical path.

[ScorpiusWireless]

Decision made, we're proceeding with PWM (digital code) instead of analogue. More firmware work but no DAC chip required.
This means if all is good we would have nailed the MPD hardware on the second manufactured version, which arrives in 4 weeks, although it will need to be thoroughly tested for data loss due to rail noise. Its still possible a minor hardware change may be required.
It also means we are one step closer to production once we test Carrera protocols, BEMF detection and current limiting. 

[ScorpiusWireless]

   

Here’s a mock up of what the Scorpius Carrera dongle will look like. A 6 wire RJ12 plug and wire is cut and soldered to MPD. 4 wires go to our 4 pin digital port and 2 wires vampire 5V off the Carrera Control Unit. 
The trade off with utilising the digital comms option over the analogue protocol is that we lose our OLED driver port. But we have a work around for that.

There is 2 uses for this dongle.
1. Nitrous system. Controller controls car direct but also sends controller data to the CU to maintain compatibility in regard to apps and ti get that important lane change signal to the rails via the CU. 
2. Use Scorpius controller only to connect wirelessly to the Carrera CU. 
The firmware for most of it is available from the Scorpius car decoder protocol firmware already complete. So for this product we need to reverse the Carrera controller code and send it to the 4 pin digital port. There is some information available online. Again it means working with the dreaded Manchester code. 
   

[ScorpiusWireless]

Ok here’s a serious mock up.

What is it? It’s a dongle that receives Scorpius throttle data and turns it into Carrera throttle data and delivers it to a RJ12 telephone plug that connects to the Carrera CU.

We now we have not just one but two 12C data ports. This negates the need of a seperate DAC chip as mentioned in previous posts here.

The blue and white wire are 12V power from the CU that powers the MPD. Phew no battery required.
The pic is based on the upcoming MPD V5 prototype coming in March with two 12C data ports not just one.
It will come with pins specifically for a reset switch pcb and a pcb mounted micro (momentary) switch.
So here I’ve replaced the Carrera reset switch with an off the shelf momentary switch connected to the 2 pins.
The OLED will be held in place by a 3D printed surround. It will be powered off the MPD.
The RJ12 plug is re-soldered to the MPD as shown.
At this stage I’m using a Carrera Dongle casing as it has a smart matching (to the app connect box) enclosure with the reset hole and screen cut out, labelling, as well as the RJ12 plug with a nice shroud where it leaves the enclosure. 
As you can see the MPDs small size makes for an easy install and everything fits nicely with room to spare.
I could also re-program an existing Carrera dongle. But we like everything hardware wise to be proprietary. It’s a possibility though and something to consider. 

Here we will simply use the proposed MPD V5 as is and only a firmware change is required.

That firmware upgrade won’t be easy. The good news is its only simple throttle signal and a LC switch signal.

The MPD “Digital wireless slot car Arduinos” adaptability and flexible interface make it so much easier to turn almost any conceivable idea into reality.


   

   

   

[ScorpiusWireless]

Refinement, refinement, refinement.
So the team reach the final design. The OLED is not required as we can use the Scorpius controller to set ID as per normal. Nor is the set button required. This saves 2 cutouts plus labour and parts. 
The RJ12 will come plugged so it is quick to install by the assembler, with only one cut out required for the cable. A Dremel comes to mind.
No power is required either since the dongle will be powered from the CU as per the OEM dongle. This saves a cable pair, a socket, soldering and labour.
So all good news.

The other good thing about this Nitrous Dongle project is the dongle is basically the Scorpius car decoder, with Telemetry swapped for info out via the data port with Carrera native throttle messages direct into the RJ12 port of the Carrera CU. All the coding for receiving Scorpius Controller data is complete.

Theres only 10 throttle levels and one brake command to code to send from the dongle to the CU and this project will be completed. In theory this is a simple task and probably just a days work, but is critical path to the Nitrous concept. Time will tell of course. And again the Multi Protocol Decoder steps up to its name being easily converted to a Scorpius to Carrera dongle fairly quickly.

But all in good time. Team Scorpius still have bigger fish to fry.

   

   

[ScorpiusWireless]

Development and testing. 
Carrera CU, Carrera 132 OEM chipped Carrera car, Scorpius controller using an ESP32.
The OEM chip has 15 step control.
But if you listen you’ll hear the transitions are smooth and you can hear a fairly good range. It’s the Scorpius 255 throttle steps being converted proportionally to Carreras 15 steps. 
This is testing the Nitrous dongle firmware using an ESP32 and Scorpius controller into the a Carrera CU. 
We also decided the Nitrous dongle needs to be separately powered as the 5V signal from the Carrera CU 
doesn’t have enough Grunt.

The video shows you can now use a Scorpius controller (using Scorpius protocols) to drive a Native Carrera system. It’s a major step forward. 

Next step is to integrate the Nitrous chipped car which is simply Scorpius car protocols. Add in our new function of the Scorpius controller being able to talk to a Carrera CU and you have all bases covered. 

So one MPD will act as Nitrous car decoder, one MPD will act as Nitrous dongle. Cheers.
https://youtube.com/shorts/x3MbhtqRAY4?s...hwBXDpjKP3

[ScorpiusWireless]

Change of plan.
Once John really dissected the Carrera dongle and CU connection we found it needs 3.3V not 5V plus a couple of other minor anomalies.
Answer? 
First thought was to make an intermediate board to make it work or to make a specialised board? 2 boards would look like a hack job so the team decided on a new specialised board.

Unfortunately it won’t fit the MPD “one board for all concept”
though. This means more set up costs and a seperate production run and although is disappointing it’s the best way forward.

The only real alternative would have been to modify one of the data ports. But if we did that the port would only ever be suited to the dongle.
So here it is. A nRF52832 powered dongle specifically designed for Scorpius/Carrera.

The 6 rectangles on the right side is set up for a 6 pin 1.5mm socket or solder wires to these same pads, which goes to the Carrera CU via its RJ12 socket.
An LED display is not required as the controller ID is already known by looking at the Scorpius controller.

The board is powered by the 3.3V supply from the Carrera CU. Simple.

This took just 3 hours to design.

This is another critical path completed. Firmware has already been written and tested so Nitrous is almost here.
The project is finally starting to come together, and in a big way. 

Development continues.

   

[ScorpiusWireless]

Firmware debugging for Nitrous Dongle using an MPD as a development board. So far so good.

We have reached a milestone.
Essentially we have nailed development for hardware and firmware on both the MPD decoder (2 protocols) and Nitrous Dongle and an array of other stuff in just over 22 months.