Just a quick update to let you know that work on the Positron is progressing well, and I expect to release a video of it in action later this week!
In the meantime, here are some beauty shots of the new RGB LED cable for the color changing cyclotron:
And a shot of the vibration motor and volume pot:
Note that the volume pot can be installed in the thrower or pack. Here it is pictured connected to the thrower’s switch module.
If installing the volume pot in the thrower it will be up to you to figure out the knob arrangement for it. You could for example install it in the knob next to the Clippard, but chances are you’ll have to shorten the plastic pot shaft and machine that knob to add a set screw. And if you’re installing it on any of the side knobs, then the pot shaft would have to be really short.
It’ll be much easier to install the pot in the pack shell, either on the crank knob or motherboard. I will be offering extension cables for it as well in case you need one.
Oh, and the vibration motor will come with a little adhesive mounting clip so it is easy to install.
As with speakers, I’m often asked what the best battery to use with my proton pack kit is.
The proton pack kit requires around 12V to function. A little less, or a little more is okay, with a 14.4V battery pack being the absolute recommended maximum. (The true maximum is actually a bit higher than this, but a 14.4V lithium pack won’t exceed that.)
Is there any advantage to more voltage? Well, not really. The gain on the amplifier is set such that over 12V the audio will begin clipping, so while it might sound a bit louder the audio quality will be somewhat reduced. So for that reason, I recommend a 12V battery pack. I designed the kit for 12V because 12V battery packs are extremely common, while higher voltage packs are more expensive and hard to come by. And the e-cig foggers that Fincher & Son sell for use with my kits are also designed to run at 12V and higher voltages will likely damage them. So for everyone’s sanity, stick to 12V.
Now there’s a lot of options available for a 12V supply, but the most common are lithium-ion aka “lipo”, alkaline, or lead acid.
The disadvantages of alkaline and lead acid are that they’re extremely heavy. Alkaline also has a high internal resistance which means the voltage droops when the amplifier in the kit tries to draw a lot of current. This kills the bass. And of course you can’t recharge alkaline, so C cells will last you a few hours, and D cells a couple days and then you have to replace them. And the voltage also drops as they discharge so the pack will get quieter over time. And lead acid, well because they’re so heavy I don’t recommend them at all, but they can source plenty of current and have high capacities. You’re on your own finding a charging solution if you choose that route, but it shouldn’t be too hard to get a charger since you can find them on the shelf at any auto parts store or Walmart.
So the battery I recommend for use with the packs is lithium-ion. Li-ion batteries have high capacities, can source large amounts of current, are very lightweight, and can be recharged easily; if you get the right li-ion battery pack.
Now, you may have heard of lipo batteries for remote control vehicles, and those are fine, but as they’re designed to supply huge amounts of current far in excess of what my kit requires, they can be a pain to charge and maintain. They have no built in protection circuits for overcharging or over discharging, and either of those can be dangerous and either cause a fire, or kill the battery.
So I recommend you stay away from those, and instead look at what are known as power banks. Power banks are often used for charging cellphones, or powering laptops and cctv cameras. The ones for laptops and CCTV cameras are the sort you’re looking for, because they’ve got a 12V output with a 5.5×2.1mm barrel jack on them, and they are capable of sourcing 2-3A continuously, which is the minimum required for the kit.
Power banks vary widely in capacity and price though. You will want one that’s at least 6000mAh for the proton pack kit, though 3600mAh or 4800mAh may be sufficient for many. 6000mAh will give you 1A on average for 6 hours, or 500mA for 12 hours. The average current draw of the kit is going to be closer to the latter, though how much it actually draws depends on if it’s playing music and how loud it is, which also depends on if you’re running with one or two speakers; so it’s impossible to provide you with an exact number. But with a 6000mAh battery, you should be fine all day at a con, and you can charge it in 6 hours overnight.
There is one problem with power banks though, and that is that there are a LOT of super cheap ones out there that are made in China that have fake specs, and use recycled batteries. Recycled lithium batteries are bad news. Friends of mine have had multiple packs die on them, and in pulling them apart and testing them I’ve found that one or more of the three pouch cells in the batteries they bought were dead, and that the batteries were manufactured five years ago, and that the 9800mAh power banks they were sold were actually more like 3600mah. I also know of one individual who had one of these cheap battery packs spontaneously catch fire.
So how can you avoid getting one of these bad recycled batteries? Good question! You could avoid them buy buying one of the expensive name brand power banks on Amazon, but who wants to spend $65 on a battery just because it says Energizer on the front and has a fancy enclosure you’ll never see inside the proton pack?
Thankfully, I’ve done the legwork for you! At least for those of you in the USA or who can purchase from Amazon. If you’re outside the US you can try to find the same manufacturer, but don’t assume that just because a battery on ebay has a black case like this, that it’s good. There are a lot of fakes built just as badly as the blue bricks above.
How do I know this is a good battery? I disassembled it!
You can see this battery is well built! Thick metal tabs connect the over current/discharge protection + balance charging circuit to the batteries, and the circuit itself looks to be of very high quality construction. And unlike the blue brick, this power bank uses cylindrical cells instead of pouch cells. These 18650 cells are very common, and have some safety features that the lighter more compact pouch cells don’t. I personally have not heard of these type of cells swelling up or catching fire. Also, check out that date code: 2016-03-03. March 3rd of this year! These batteries were made only two months ago! No recycled crap here.
Unfortunately I can’t tell by the numbers on the cell what its capacity is, so there’s no way to know if I was cheated on that, but based on the number of cells and the minimum capacity you can get these cells in, there should be at least 4800mAh in there, and based on how long the pack took to charge with the 1A charger they supplied, the advertised 6000mAh is probably accurate.
This power bank unlike the blue batteries doesn’t have two cables coming out of it, but it does come with a Y adapter cable that serves the same purpose:
And here you can see how you would connect the charge port and power switch harnesses for the proton pack kit to the battery:
Finally, if you must order a battery from ebay, then I would look for one with screws on the back like this one. Screws on the back means they aren’t trying to hide what’s inside. And it means you can check to see what’s inside. You could also ask the person selling the pack if it contains 18650 or pouch cells and if they are new. Pouch cells aren’t necessarily bad if you know you’re getting new ones. I just suggest trying to avoid them because it seems like all the fake batteries use those because those are what are found in most used cellphones and laptops and other used electronic devices. The 18650 cells are most often used in power tools, and nobody throws those out until they’re good and dead.
Fresh off the presses from Macrofab, the prototypes for my Positron Proton Pack Kit arrived this weekend!
Video of it in action will be forthcoming, just as soon as I can port all the code from the original kit over to it. A short video demoing the bargraph and sound should be soon-ish as I’ve already ported that code, but the rest will probably take a couple weeks.
If you use 8 ohm speakers, or wire your 4 ohm speakers in series, they will each output half the power and your volume will be halved, and you would be adding extra weight for nothing.
There is typically room in the pack under the cyclotron for a 6.5″ or 6×9″ speaker, and by the powercell there is room for a 4″ speaker. A 5.25″ speaker may fit near the powercell however if you face it towards the motherboard, but in this case it would be wise to drill some holes or install a grille to allow the sound to escape.
A bigger speaker = louder + more bass, but also more weight. 6×9″ speakers are MUCH heavier than 6.5″ speakers.
Every 3db increased sensitivity = double the volume!
A wide frequency response is desirable, and 2-3 way speakers for cars come with a built in tweeter or two which makes them ideal.
As for specific recommendations, I used to recommend the Pyle Blue label, as they are low in cost and are among the highest in sensitivity, but the ironically named Phantom Boss Ghost series in the same price range appear to be slightly better.
The Boss Phantom Skull are also good, and appear to be identical to the Ghost and come in a few sizes the Ghost does not, but they have red LEDs on them that are synchronized to the music. You could paint over the LEDs or cover them in tape, but the most obvious exposed wires leading to them also power the tweeter and the wires that go to the LEDs are tucked in under the tweeter and very hard to get at.
If money is no object, I might try to squeeze a 6.5″ and 5.25″ speaker in there. If money is an object, or weight is an issue a single 6.5″ speaker would be adequate, and you could sell the spare since they’re sold in pairs, or a pair of 5.25″ speakers might be a good choice. If money and weight are no object, a 6×9″ speaker and 5.25″ speaker would be the loudest. But proton packs are heavy as it is, so a single 6×9″ speaker may be a good compromise for weight and loudness. It’s really up to you. There is no best option!
Most in the past I believe have gone with a single 6.5″ speaker, and those that want more have been using a 6.5″ and 4″, but I’m not sure the 4″ is really worth it after installing one in my friend’s pack that I use for demos. I didn’t drill holes in his motherboard for it though. A properly installed 5.25″ would certainly be an improvement however!
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.
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.