Does anyone have a MiniMiles pcb design?

[Chris_1]

If anyone does then please contact (chris_obbard@hotmail.com) me.

[Ozzy]

MilesTag and Mini MT suit themselves quite well for building onto veroboard material.

PCBs can save time and work, if you're planning to do a batch of 20 or so. Would a PCB for larger (1206) surface mounted components be OK, too?

[Xenon]

The next edition of my MilesTag tutorial will include a programmer and PCB for the Mini-MilesTag series, along with the usual instructions. I will release it soon, but it won't be posted on the MilesTag site for a while as Jim is still in the process of moving. If anybody wants it before then, I can email it to them.

[milestag]

The design for V2.xx will be revamped soon. I am switching to a 14-pin PIC (it's cheaper than the 12F683) and getting rid of the voltage regulator. It will be designed to run on 6xAA batteries, with 3 cells, 4.5V, feeding the electronics. The full 9V will be used to feed the IR LED. Still no LCD, but with the additional pins you will be able to add on the ISD sounds as an optional upgrade. A jumper will select ISD or piezo sound.

I will be selling kits including the PCB, preprogrammed chip and all electronic parts required to make a MilesTag gun. You will just need to make the case and lens tube. The target price range will be about $20 USD.

As always, all source code and schematics will be available for free on the MilesTag website.

[Xenon]

Will the previously intended update to the PIC12F683 take place? Or will this transition be between the PIC12F629 straight to the 14-Pin PIC?

[Chris_1]

The next edition of my MilesTag tutorial will include a programmer and PCB for the Mini-MilesTag series, along with the usual instructions. I will release it soon, but it won't be posted on the MilesTag site for a while as Jim is still in the process of moving. If anybody wants it before then, I can email it to them.

Can you e-mail it to me please?

Chris_obbard@hotmail.com

[milestag]

Will the previously intended update to the PIC12F683 take place? Or will this transition be between the PIC12F629 straight to the 14-Pin PIC?

straight to the 14-pin PIC

[Xenon]

Great. Anybody want some PIC12F683's? :(

[Rommel]

That part kit sounds like a very good deal.

[EDantes]

...It will be designed to run on 6xAA batteries, with 3 cells, 4.5V, feeding the electronics. The full 9V will be used to feed the IR LED...

Is the voltage regulator really that expensive, or is there another reason for removing it?

~Luke

[Ozzy]

The regulator can still be added to the design, if you don't want to tap the microcontroller's voltage from between the 6 batteries/cells. Most low-voltage 5V PICs can run at down to 2.7V, so it's well within margin.

Just ensure to have a good filter for the MCU voltage and solid ground in the design to avoid potential trouble with the nonregulated supply voltage.

[milestag]

I'm trying to use the 2.xx design to demonstrate the most inexpensive possible design (and lowest parts count) without cutting too many features. The biggest request I've seen for upgrades to 2.xx is the addition of digital sounds, and I agree the sounds add ALOT. By using the 14-pin PIC (16F636) I can reduce the cost AND leave room for expansion.

The regulator does add a little to the cost, and it's an unnecessary additional drain on the battery. I will probably include a place for the regulator on the PCB though so you have the option to add it.

[rectifier]

Isn't tapping a pack in the middle bad for the cells (uneven discharge and charge)? I suppose the drain from the PIC itself is pretty negligible next to the IR LED, so it doesn't really matter in this application?

On the original topic, you can free-form the miniMTs easily enough if you want to make them really tiny. Or if you just like free-forming circuits, like me :D

[EDantes]

I just use a bit of perf-board... I've worked out a layout where the final circuit is smaller than the driver board on the back of the LCD. Works nicely, and saves a lot of work with the PCB etching.

~Luke

[Builty]

Apparently in the LTTO's (which use a tapped power supply too) there have been reports of noticable inequal battery drain.

[Xenon]

The unequal battery drain shouldn't really matter too much unless you are able to drain the pack completely, in which case the cells that become 'flat' first may have the other batteries trying to reverse their polarity by pushing current through them. I doubt the Mini-MilesTag system would be able to deplete the whole pack to this extent; you'd notice at least some errata way before you reach the dead point of a NiMH pack.
This kind of thing is a problem in RC cars and planes as they usually make the battery pack scream in pain before they stop, and if you have a single cell that was lagging a bit for whatever reason, you would probably end up with a ruined cell.
I'm not sure about the implications of charging an unevenly depleted pack, but I wouldn't be surprised if it was much the same.

[Builty]

Not sure what you mean by pack in this context; you can only split off a mid-voltage if you use seperate cells (unless you hack into the packl and try to find a connection point.)
I'm not saying its a big issue, just that I've read some of the LTTO guys complaining about it.

[Ozzy]

True. The IR emitter drain is actually negligible when compared to what the LCD backlight and other small things (LCD, processor, TSOPs) eat while continuously enabled. This becomes especially apparent when playing on a large "battlefield" with a long idle time between actual skirmishes.

Some calc on current draw by time;
Sensors ~8 mA
Processor ~2 mA
LCD Backlight ~25 mA

That adds up to a continuous drain of about 40 mA. When operating, the IR emitter and muzzleflash drain approx. 1000 mA at a duty cycle of less than 1:10. That compares to a current draw of 100mA. When firing at a rate of 2:5 (2 shots every 5 shot lengths) it's equal to the tapped voltage current drain.

And then there's the problem with the transmitter current loop - the receiver voltage varies with the transmitter voltage. It's a suitable option for "toy" systems like the LTTO, but IMHO the regulator's current drain and price are not that much when compared to the problems.

If going with that solution, use plenty of filtering for the tapped voltage.

[Builty]

The average LCD backlight current (for led array types) is actually closer to 100 -150 mA.

[Ozzy]

Whoop!

The types I have (bought a dozen from a jumblesale) only draw at about 50mA, and I've cut it down to 25 with a series resistor. Apparently they don't need one after all.

They did seem a little dim, but quite readable in darker conditions ;)

[Xenon]

The average LCD backlight current (for led array types) is actually closer
to 100 -150 mA.
That’s quite surprising, Builty. I can see why you've implemented the automatic power switching for the LCD screen in FragTag. Over a few hours it must make a great difference in battery life.

Back to the main topic though, the Mini-MilesTag set doesn't use an LCD screen, so any amount of current drawn by it is discountable.

[milestag]

The new MiniMT PC board will allow operation with a "tapped" battery, or you can optionally install a 78L05 regulator and use a 9.6V rechargeable pack. Or sub in an LDO regulator and use a 7.2V pack, etc, etc....

Based on the above discussions it seemed worth it to have all the options available since it doesn't change the size or price of the PC board to add a couple more pads for a regulator. Keep in mind I still have to actually TEST the tapped battery configuration to see if it works okay.

[Builty]

That’s quite surprising, Builty. I can see why you've implemented the automatic power switching for the LCD screen in FragTag.

That plus its hard to be stealthy in night games when you have this big green glow coming from you gun all the time.

[xnihilo]

As always, all source code and schematics will be available for free on the MilesTag website.

Can we have the source code for current MicroMT firmware and for 5.30 MT firmware?

[milestag]

Wow, this is an old thread!!

Full source code is still available for some of the older versions, but not the newest releases.

[xnihilo]

Why can't we have the latest source code? It's not for putting it on the market in some 'Super Phaser 2000' but to implement some personnal features as the one I talked about in a post: remove the hit led staying on when tagged out so I can use the hit led signal for a killed state physical feedback. As you are too busy for a request such a mod in the firmware, it would be easier for me to recompile the source once I have made the change. I won't mod an old source code as I want to be using MicroMT with 5.30 firmware for my rev G 5.XX guns. What do you think?