WIP & Refinements

Curently, now the Sensors have been updated following the feedback from Babylon 5, I’ve started working on one of the refinements to the emitter circuits to make them a little cheaper (less componants) before fully publishing everything.

It can be summarised as changing the way the signal sent to the IR emitter is generated.

The current circuits, PPG and in-development use an EXTERNAL signal modulation method – this is the easiest to code, but needs additional external componants.

In this it uses the PWNOUT command in picaxe basic to generate the 57.6kHz carrier signal on 1 pin, and the 1800hz “Hit” signal on a different pin. These two signals are then fed into an external AND gate made from transistors and then, (depending on power output desired) fed into a Mosfet to drive the emitter.

For the data signal, it replaced the hit signal output on the pin with the serial data output after 50 mS, using the Picaxe basic command to generate serial data via the software on any pin. Relatively simple and working fine now.

The refinement in development however takes advantage of some of the modules built into the PIC chip that is the core of the Picaxe to output a fully modulated signal on a single pin, without needing the components for the external AND gate – the payoff is it’s more difficult to code.

In a nutshell –

It tells the PWM module that generates the PWM  “carrier” and “hit” signals module to not output to the physical pins

Then tells the Data Signal Modulator to use 2 PWM module outputs above as the input.

Triggering the signal is a case of switching the ”hit” signal generation on or off depending.

For the data signal, it’s a case of telling the Data Signal Modulator to use the serial signal instead of the Hit signal

The part I’m currently working on is the switch between Hit signal and Serial data signal - I’ve got the serial data outputting on the Serial out pin. I need to get it switching off the physical pin output for the serial code and also changing the source for the 2^nd input to the data signal modulator. I’m hoping to have it done by the end of the weekend.

Overall though in the end it’ll be worth it, as while the external modulation is quite simple to code, it is a little more expensive components wise, and this is essentially a refinement to get the costs down

Finally....

Well this has been an odd weekend.

Problem found with the mosfet circuit (see prev post for video) is down to the logic gate on the breadboard be8ng configured as a NAND gate rather than an AND gate, which meant the thing was on all the time... Which is a bit of a bugger when the resistors are specced to on,y deal with the amount of power in short pulses.

Hey ho. Sorted now.

Now I’m finally getting round to updating the startup sequence for the sensors based on the feedback at the game....

See you on the other side....

Not a productive day.....

Well, today I picked up m new bench power supply, meaning I can get on with the higher power output circuits, driving the emitter at 1.5A.

Somehow, I don’t quite think I’ve locked that particular circuit down just yet.

There’s a lovely smell in the workshop though.....

Woohoo!

So,

Little bit of an announcement today: As mentioned here I was going to have to re-invent the wheel with a data transfer/WoW pulse signal.ess

As of last night... we have success!

 And given it's based on the pre-existing code I'd done that was compatible with WoW, DoT and Lotna sensors, It still works with everything it did before, as well as WoW and Dot baseline (In that it recognises a 'hit' has come in AND the emitter version works with baseline Wow, Lotna and DoT sensors as well.

Now to sort out the little tweaks to the startup for the sensors mentioned in the last post then its documenting time for the basic stuff and refining whats going into the data system.

TTFN
Ady

Now the dust has settled.....

Well. The Babylon 5 game has been and gone now, so time to start working on future stuff.

 

Bit more of a text wall this time…