Positron Prototypes Ready for Manufacture!

Finished the last of the design work on the Positron Proton Pack kit today!

Switch Module
LED Module
Extension Module – Connects to CAT5 cable and fits inside thrower handle.
RGBW Strobe – Color changing main strobe for both proton pack and trap kits.
White Strobe – Used for grille light upgrade and/or n-filter, and can be added to trap kit .
Trap Kit Bargraph – A variation on the normal bargraph which may or may not feature in the final kit. Only difference is it includes a location for one extra LED.

Positron Strobe

Finished the layout for the color-changing (RGBW ) strobe today:


You may be wondering why it has mounting holes.  The mounting holes aren’t there to attach it to the acrylic tube!  They’re there because the same strobe will be featured in the trap kit I will be releasing soon after the proton pack kit, and because I will be modifying this design slightly to create a white version for the super bright grille light.

The Fresh Positron of Bel-Air

Now this is a story all about how my PCB got flipped, turned upside-down!


I was putting the finishing touches on the Positron’s layout the other day when I decided to fix something that was nagging me for quite a while.

When I began working on the Positron, I placed the power connector along the bottom of the board near the 5V regulator.  This location made a lot of sense, both from a power distribution standpoint, and because the main power switch, which is attached to the cable, is usually placed towards the bottom of the Proton Pack.

As I progressed with the design however, and I determined where it would be best to place the CAT5 connector for the extension cable and the connector for the speakers relative to the chips that drive them, I realized I had a problem.   Both these connectors ended up at the top of the PCB, but both also connected to things that would be towards the base of the Proton Pack.

In addition, the CAT5 is the heaviest and the least flexible of the cables, so having it exit to the north and then do a u-turn to head south wasn’t ideal for a variety of reasons.

It was at this point in my thought process that I realized when people went to install the kit  they were either going to mount the board upside down or sideways in order to better orient the CAT5 and speaker cables.

That would make it hard to read the stencils, but even worse,  it would mean the power connector would be oriented towards the top of the pack, opposite the direction in which it needed to go to head towards the power switch at the base.

Thankfully, when increasing the size of the bulk capacitors I had to increase the size of the board, and this extra space enabled me to shift them to the top of the board and place the power connector alongside the speaker connector!

Long story short, I decided that it would be best if I rotated the board 180 degrees, flipped the stencils, and mounted the power connector on the bottom alongside the speaker and CAT5 connectors.


Positron Switch Harness + Charge Port Cable


Power switch harness and charge port cable add-on for the Positron Proton Pack Kit.

Designed to be used with the 12V rechargeable LiPo battery packs you can find on ebay.

No soldering required!

Switch harness is 6′ long with the switch mounted in the center.  Charge cable is 3′ long. 

Arcoelectric toggle switch is extremely rugged, and attached to the cable with quick connects.

Positron Layout

Thought you guys would like to see the latest and near-final layout for the Positron’s PCB!

Final Positron PCB Design

As you can see, a lot has changed since the first prototype:

First Positron Prototype

Among other changes, the audio system has been overhauled, with a dedicated high PSRR regulator for the DAC to keep noise in the system to an absolute minimum.

In layman’s terms, a Digital to Analog Converter converts digital data to an analog  audio signal for the amplifier.  And that DAC is supplied with 5V from a linear regulator from the 12-14.4V primary supply.  This regulator has a high Power Supply Rejection Ratio which means that any voltage swings on the 12V supply will be reduced by a factor of 100 before reaching the audio system.

You may also have noticed the board has increased in size.  The original was 2.25×1.5″.   The final board will be 2.5×1.75″.   I needed the extra room for the Cat5 cable connector, but that allowed me room to improve the routing, increase the size of the bulk capacitors, and add a dedicated connector for the volume control.  I also beefed up the power connector slightly.

The I2C connector pictured above is where you will connect the Flat Flex Cable for the powercell (or bargraph on the eventual trap kit).  Directly above it is the Cat5 cable connector which goes to the thrower and the modules in there.

The SPI connector in the center won’t be populated, it’s for future expansion.  In the trap kit, it will be used to drive a color changing strobe if desired.  The ISP and TX/RX connectors also will not be populated, they are for programming and debugging.  I am undecided if ports 1-6 will be populated.  They are for switches and I currently have no plans for any feature which would require adding switches to the pack itself.  All the switches for controlling things will be in the thrower, aside from the main power switch, and optionally, the volume pot.

Ports 8-12 will be populated of course, with their primary purpose being triggering the relays on a fog machine upgrade.  They will also trigger when different weapons are activated.

While I’m listing features,  I may as well mention just in case you’re unaware that there’s a 20+20W amplifier on board which is capable of driving 40W total into two speakers with a 12V supply.  That’s 4x what other kits can supply, and it’s as loud as the Lepai amplifiers that were often used with my previous kit.  The smaller Dayton amplifiers that were also often used with my old kits were 15+15W.

Positron LED cables


Just got in the new connectors and ribbon cable for the slo-blo and cyclotron LEDs! 

The cyclotron LEDs will be attached to a 16p cable that splits into four at the end while the slo-blo pictured above above is just a single six inch long 4p cable. 

The six pin cable above is one of the old kit’s ribbon cables.  I placed it there as a size reference so you can see just how much smaller the new ribbon cable connectors are. 

Only the cyclotron and slo-blo LEDs will be attached with ribbon cables.  Other individual LEDs will use 2p JST PH connectors, and all the modules will connect with the 6p flat flex cables seen in previous updates.

Positron Thrower PCB progress

thrower-081In addition to the Pixel I’ve been hard at work on the Positron Proton Pack kit.  What you see here are the near-final designs for the boards which will go in the thrower.

Unlike the old kit, the new kit uses polarized JST connectors for the LEDs, so you can’t plug them in backwards, and they’re clearly labeled to make it easy tell which one goes where.  The color changing slo-blo LED also features a polarized ribbon connector like the one which will be used on the Powercell module for the RGB LEDs.

The strobe/switch module is packed with features.  Up to six switches can be connected (the kit comes with five, the sixth may eventually be a mode changing switch), and there are four servo-like connectors which can be used to trigger relays or to activate a super bright vent LED.  The module also contains circuitry which can directly drive a vibration motor or two, and/or provide a high current 5V source for an LED flash bulb.   And of course, there is a connector for a supr bright color changing LED strobe.

Finally, the Extension module plugs into the end of the CAT5 cable that carries power and data from the pack to the thrower, and fits neatly inside the handle of the thrower to maximize the space inside the thrower’s body in case you have a tip extension mechanism.  The module has connections for three flat flex cables to connect the two modules above and the bargraph module, and in addition it features a connector for a rotary encoder so you can place a volume control inside the thrower if you wish.  (The same connector can also be found on the Positron itself, so if you want the volume control on the pack nstead, you can do that as well.)

Positron Thrower PCBs

They’re not quite finished yet, but they’re getting there!


The one on the left connects to the CAT5 cable and the bargraph, LED module, strobe, vibration motor, and switches then connect to it.

The one in the center is the new LED module for driving the 5mm LEDs in the thrower, including one for the vent should I decide to offer a lower priced kit that forgoes the new and expensive super bright LED for the vent.

And the board on the right is the old LED module, for size reference.  The new boards are only 1″ wide!