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  • gumby3344 11:03 pm on January 23, 2013 Permalink | Reply
    Tags: , , , , ,   

    Making a Paintball Gun from Scratch – The Build 

    Once Brian had gotten his design work fairly completed, we knew it was time to dive in and start our construction. I got a free weekend and headed up to Brian’s for a long day of trial, and hopefully not too much error!

    We decided to start work on the smallest and most simple part to sort of “get our gears turning” on the lathe. 😉 This part was the bolt stop, as shown in the picture below and depicted in yellow in the previously posted CAD screenshots. We somehow proceeded to pull it off without a hitch and moved on to some more “interesting” parts.

    Bolt Stop

    2013-01-15 22.11.022013-01-15 22.11.11

    (Read the rest of this post…)

  • schoolie 9:35 pm on January 13, 2013 Permalink | Reply
    Tags: CAD, , , ,   

    Making a Paintball Gun from Scratch – Design 

    After selecting the Smart Parts Ion as the basis of our paintball gun project, the next phase was to get the design details worked out. Designing on paper is a lot more efficient that trying to work out details in metal as we were doing when we started the project.

    The main goal of this part of the project was to get detail drawings made of each component, with the analysis to back them up and ensure the gun will function as desired. Ideally, this work would be done in a solid modeling package with detail drawing support. At the time, I hadn’t found a good solution that was in my price range … I mean free. Fortunately, I stumbled upon Creo Elements/Direct Modeling Express, which fit the bill nicely. I’d highly recommend checking it out if you’re looking for a solid modeling CAD program for hobby work.

    With the CAD question answered, we needed to get started on the design. Again, was a great resource. The cross-sections, animations, and functional descriptions were extremely helpful, and enabled us to reverse engineer the Ion without having access to one.

    Instead of simply copying the design, we wanted to make a few changes along the way. Our design should operate on 90 psi and uses standard NPT fittings rather than microline. These changes facilitate hooking the marker up to an air compressor, and minimize the cost of hardware we have to purchase. Using an air compressor should allow us to do some initial testing of the firing assembly without having to make or buy a high pressure regulator like you’d find in a regular paintball gun. We also simplified a few areas of the gun to better suit the limited capabilities of my shop.

    The drop in pressure required some math to determine the required dump chamber volume. Without going into too much detail, we put together a spreadsheet to calculate the velocity of the paintball as a function of chamber volume and operating pressure. It’s surely not exact, but it should be close enough to work. Here’s the predicted projectile velocity as a function of time for 80 psi in the dump chamber in our design:

    (Read the rest of this post…)

  • jschoolie 10:03 pm on January 8, 2013 Permalink | Reply
    Tags: Alesis, , , garageband, , io, iO2 Express, iPad, iPad io, iPad recording, iPad3 io   

    iPad 3 Compatible Alesis iO2 Express Mod 

    I was wanting to come up with a way to record my guitar among other things with my iPad without having to drop the $180.00 or so on an Alesis iO dock that honestly wasn’t as functional as what I wanted. Plus, I had heard a lot of reviews saying that the iO Dock didnt work with the iPad 3. So, I started scouring the Internet looking for a better solution. That’s when I stumbled upon the iO2 Express by Alesis. I was thrilled when I saw that this device was about $100.00 less than the iO Dock. The only thing stopping me from buying the device was the fact that I would have to modify it a bit to make it work with my iPad (the iO2 Express was intended to be used with CubaseLE on a PC or Mac). After buying it, I realized that I had a little more work to do than what I thought.
    To make the device work with my iPad I had to isolate the iO2’s power from the iPad because the iPad couldn’t provide enough current to power the device. So, I opened up the iO2 and removed the existing USB B female jack, making sure to remember which pin was where (i.e. power pin, ground, data+, data-). Next, I made a Franken-cable of sorts to provide +5V to the iO2. I cut the head off of one end of an instrument cable and I also cut the head off of one end of a USB cable leaving the USB A head that normally plugs into a computer. I stripped off the end of both cables to expose the inner wires. On the USB cable there were five wires: Red, black, white, green, and bare. The red wire is the +5V power line, the black is ground, white is data negative, green is data positive, and the bare wire is the chassis ground. The only wires I cared about were the red, black, and bare ones. On the instrument cable, there were two wires. One was the inner insulated wire which went to the tip of the plug and the other was the outer bare wire which went to the sleeve of the plug. I attached the red wire of the USB cable to the tip wire of the instrument cable. I also attached the black and bare wires of the USB cable to the sleeve wire of instrument cable. Finally, I wrapped each connection with electrical tape to ensure good insulation to prevent shorts. On to the iO2. On the PCB of the iO2 I installed a female instrument cable jack. I attached the tip connection to the +5v pin and the sleeve connection to ground (note how this corresponds with the Franken-cable’s setup). Next, I mutilated yet another USB cable again cutting off the head and leaving the A end intact. This time, I wanted the black, white, green, and bare wires. I attached the green wire to the data+ pin, the white to the data- pin and both the black and bare wires to ground. Finally I slapped some electrical tape on there to try and hold everything together and to provide insulation. You can see in one of the pictures where all the wires go. I just attached the bare wire to one of the old through hole mounts for the original female USB B jack.
    Beyond the mods to the actual iO2 I had to buy the Apple Camera Connection kit for about $20 on Ebay. I also had to buy a USB hub because for some reason the iO2 won’t work with the iPad without it. It seems almost as if the hub tricks the iPad. That’s the only part of this whole thing that I honestly have no idea why it works. I found that fix by googling some iPad forums. Anyway, when operating the device, use the Franken-cable to provide the iO2 with power. I just plug the USB end into my Apple charger because it outputs +5V (any other USB based charger should work) and I plug the instrument cable end into the jack I installed on the iO2. Plug the USB cable that has its data pins connected to the iO2 into the USB hub, plug the hub into the Camera Connection Kit, and plug the CCK into the iPad and it should work…hopefully.
    I’ve really gotten a lot of use out of this setup. I use it for recordings a bit, but much to my surprise, I use it quite a bit more as an interface with an oscilloscope app I found in the App Store. Believe it or not it works pretty well! We tested it against an actual analog oscope to find that the waveforms look the same and measure about the same as well! All in all, I put about $100 into the project which was totally worth it in my opinion.iO2 PCB with Female 1/4" Jack and new USB Cable

    Wiring on iO2 PCB

    Whole Setup (Minus iPad)

    Screenshot of My Oscope App

    • Raymo 10:52 am on October 16, 2013 Permalink | Reply

      Hey, did you try a self powered hub, I’m just wondering if this would have worked rather than having to do the power mod to the io2

    • len 5:13 pm on December 17, 2013 Permalink | Reply

      Cool mod 😀 hey I have one of these too – It won’t power on via an apple USB charger tho or HTC? I like to use with a HV30 camcorder on the go via beachtech XLR inputs. Power is the only issue – I guess I could carry a laptop with it all hooked up. Can this run stand alone from a USB charger tho? thx bro.

      • jschoolie 8:44 pm on December 18, 2013 Permalink | Reply

        Thanks! I believe it needs to have an actual USB data connection for it to power up, but that’s just a guess, not a fact.

    • len 4:10 am on December 19, 2013 Permalink | Reply

      Yes – Tried via a few chargers does not power on – lookd like windows XP driver once loaded nothing to download 🙂 then it powered on – old T23 with the lid closed – setup power and lid switch first in CPanel not to sleep – is used for car data logger so already set. 🙂 now mobile just bit heavier chunky T series – has better shielded usb ports compared to most netbooks – these are USB1 and still works. HV30 sees a good signal in via DXA-4 balanced TRS outs from iO2 to XLR. Another good find was the HV30 actually can use a SM7B x DXA-4 without the iO2 – works ok – and a little better with the i02 gain around 1/2 to 3/4. iO2 now provides phantom powering within the budget.”Hard wired LAV” setup . Cant fault this for price .

    • Mark 5:21 pm on December 28, 2013 Permalink | Reply

      Looks like a cool set up. I bought a m-audio m- track plus and when I used it with garage band I had some delay and bad quality because it was not working great with garage band. Have you experienced any problems with using the interface itself other than the power issue?

      • jschoolie 5:07 pm on December 31, 2013 Permalink | Reply

        Thanks! Nope, I haven’t experienced any trouble or delays with Garageband or any other app that uses the usb audio interface using this setup.

  • schoolie 12:09 pm on January 8, 2013 Permalink | Reply
    Tags: , , , ,   

    Making a Paintball Gun from Scratch – Getting Started 

    Ben came over for the weekend a couple of months ago, and we were looking for a project to do in my fledgling machine shop. He’d never really used machine tools, and I hadn’t done any “real” machining in my home shop yet, so we were looking for an excuse to pick up some experience.  Ben’s in to paintball, so we decided to try to make a paintball gun.

    We tossed around making a Spyder clone since that’s what Ben’s taken apart the most, but decided not to because I wasn’t sure how we could make the stacked tube housing with the tools currently in my shop. Keeping things to a single centerline makes them a lot easier to make on a lathe!

    The next type of gun that came to mind was the Tippman style marker.  They work on basically the same principle as the Spyder, but are arranged in a straight line rather than two stacked tubes. However, neither of us had ever owned a Tippman, so we couldn’t just make up the design from memory. We did a bit of research and came across a great site in With the info on that site, and a few crude hand sketches, we headed out to the shop to “get something done.”

    Ben running the Lathe

    (Read the rest of this post…)

  • schoolie 12:15 pm on November 12, 2012 Permalink | Reply
    Tags: , , , , ,   

    MC2100 PWM Controller Schematic 

    Just a quick update. I haven’t finished the permanent driver board, but thought I’d upload a better version of the schematic. I’m currently trying to decide if I’ve messed up the MC-2100, or if my soldering just sucks. At this point, I’m getting the motor to come on, but not consistently like it was with my breadboarded circuit. The indicator LED will flash 5 or six times, and the motor starts turning, then the LED goes back solid like it’s not getting signal, and the motor slows back down. I’ve had a couple of occasions where the motor will run up to full speed, so it’s at least close. I can at least confirm that this circuit worked on the breadboard, as shown in the previous post.

    Schematic of PWM Driver

    I also wanted to post a few of the relevant files I’ve found pertaining to the MC2100.

    Here’s the document that describes how the controller is interfaced with the treadmill, and the function of each pin of HD2 on the MC2100.  This is essentially the same file that James linked to in the comments on my previous post.

    The following file has been extremely helpful in troubleshooting the MC2100 itself as I’ve messed it up along the way.  The file was provided by a member of the Home Shop Machinist forums in this thread.

    Reverse Engineered Schematic


    Check out the rest of the MC-2100 Project Here

    • Darrel 12:01 pm on February 6, 2013 Permalink | Reply

      You might have opened my eyes now with this cheers

      • schoolie 12:06 pm on February 6, 2013 Permalink | Reply

        Great. Hopefully it’s helpful. Let me know if I can clear anything up!

    • chris 1:40 pm on March 30, 2014 Permalink | Reply

      hey, i’m trying to do the same thing. wondered if i could ask you a couple questions… chris

    • Ian Grant 11:57 am on April 1, 2014 Permalink | Reply

      Very impressed by your expertise and wondered if you’d be kind enough to help me.
      I have a treadmill with the MC2100.
      The belt motor is definitely OK and I think the MC2100 is ok too.
      It seems that the console is not sending the right signals.
      Occasionally I will get it to run and the led blinks as it should.
      The only functionality I’m trying to achieve is control of the motor and even 0-5mph would be OK.
      What inputs to HD2 are required to make this happen?
      Any help would be hugely appreciated – the wife is desperate to get back on her treadmill and I need the brownie points!
      Thank you

      • schoolie 9:23 am on April 2, 2014 Permalink | Reply

        Hi Ian, the best simple circuit I’ve come up with to replace the console is in this post. It uses a 555 timer and a comparator to generate a ~50ms period variable duty cycle 5v square wave. The HD2 connections are shown on the schematic. The circuit uses a potentiometer as the user input.

        Let me know if you have any questions, or if the schematic doesn’t make sense to you.


        • Ian Grant 8:42 pm on April 3, 2014 Permalink | Reply

          Hi Brian,
          Many thanks for your reply – much appreciated.
          Prior to your reply, I’d drilled down a bit deeper and came across Terry’s circuit which I’ve bought the bits for and have started to build, but maybe I should have gone for the one you suggested – or maybe either will work Ok.
          I’m very rusty on all this stuff. I’m a 65yr old Brit currently in America – where are you located out of interest?
          I’m immensely grateful for this blog (without which I wouldn’t have been able to get started!) and for the input of you fine folks

    • schoolie 10:38 pm on April 3, 2014 Permalink | Reply

      Terry’s circuit should work fine as well, they’re just two different ways to accomplish the same basic goal. I’m in central Indiana. Let me know if you run into any problems asking the way. It’s cool to see people using this stuff 🙂


  • schoolie 2:16 pm on October 11, 2012 Permalink | Reply
    Tags: , giant fresnel lens, magnesium ignition, ,   

    Giant Fresnel Lens, Magnesium, and a little bit of Thermite 

    My friend’s old big screen projection TV died, and he gave me the screen from it.  The neat thing about big screen TVs is that one layer of their screens is a Fresnel Lens.  People have used these for starting fires and lots of other stuff, and we figured we’d join in.  Ben wanted to try making thermite, so we decided to try using the Fresnel Lens as the ignition source.  After making a crude frame and lining it up with the sun, we were able to light magnesium (from the lower casting of a broken mountain bike fork) on fire quickly and easily.  According to Wikipedia, Magnesium’s autoignition temperature is 883F!

    The thermite was home made, thrown together the night before from rust powder from an old bucket of metal junk and aluminum shavings made with a hacksaw.  We didn’t have much success actually lighting the thermite, but we did manage to get a couple tiny blobs of molten iron.

    We did this at the end of May 2012, here’s the video:

    • schoolie 3:44 pm on October 11, 2012 Permalink | Reply

      I love how fast our excitement about lighting the magnesium faded into disappointment that the thermite wasn’t working 🙂

    • littleschoolie 1:40 pm on October 20, 2012 Permalink | Reply

      We definitely need to start cutting the audio on these things… 😉

      • schoolie 9:50 pm on October 20, 2012 Permalink | Reply

        Haha, I thought that was the best part! We were screaming like little girls when it first lit, lol.

  • schoolie 10:34 pm on September 26, 2012 Permalink | Reply
    Tags: , , , , ,   

    PWM Board for MC-2100 Treadmill Motor Controller 

    Free treadmills from Craigslist are a great source of DC motors and motor controllers for machine tools.  A quick search will yield several examples of people repurposing these motors and drive for drill presses, lathes, and various other equipment.

    From what I’ve seen, the MC-60 type controller is by far the most common in low end treadmills (the type you typically can get for free).  Three out of the four treadmills that have passed through my garage have had the same MC-60 controller, and nearly identical permanent magnet DC motors.  This controller is relatively easily repuroposed as a machine tool drive, as the input is a simple voltage divider circuit driven by a potentiometer.  Just take the pot off the treadmill’s dash, mount it to your bench, and you’re up and running.

    The MC-2100 proved to be a bit more complicated.  My first clue was the all digital dash on the treadmill it came out of.  A quick google concluded that the MC-2100 required a 5v PWM signal with ~50ms period.  I found a good reference circuit on the All About Circuits forum (Link):

    This circuit has two stages.  The first is an astable 555 vibrator.  Tapping off the capacitor charge pin (Pin 6 on the 555) results in a sawtooth output, with the frequency set by R1, R2, and C.  This sawtooth is then fed into a LM393 voltage comparator to convert the sawtooth wave into a square wave.

    Here’s my final circuit sketch:

    And a quick first test video:

    In my opinion, it was worth the effort to figure out because the MC-2100 is a high frequency PWM controller, as opposed to the MC-60 which is an SCR based controller that operates at line frequency.  This results in a much quieter motor.  Also, based on a couple quick test cuts, the MC-2100 seems to have a higher current capacity.

    Check out the rest of the MC-2100 Project Here

    • James 2:17 am on October 22, 2012 Permalink | Reply

      I have the same treadmill motor controller with a motor that I’m planning on using on a metal lathe (I recently had to sell my old Atlas 618 and I’m planning to buy a smaller taig lathe and want to have the motor & controller resolved before I buy it). Your hand drawn schematic is a little difficult to read in some parts and I was wondering if you could provide a higher resolution image. I have some basic electronics experience and a few 555 timers laying around, though I certainly would not be able to engineer this circuit on my own. If you don’t mind too much, I may ask for some advice along the way as well if I run into any problems.

      • schoolie 8:44 am on October 22, 2012 Permalink | Reply

        I’m working on getting this design soldered onto protoboard, and making a few tweaks along the way. I’ll get a better schematic put up once I get everything checked out and verifed working. I wouldn’t mind answering a few questions along the way either.

        • James 1:35 pm on October 22, 2012 Permalink | Reply

          I’ll stay tuned. Thanks.

        • James 2:55 pm on October 25, 2012 Permalink | Reply

          I had a few old Arduino boards laying around. I relearned how to program them and came up with this simple code (pasted below for anyone looking to do this in the future) to run the motor off of a trim pot. It works perfectly. I had read that the controller likes a frequency of 51ms, mine likes 49 or 50ms, which is what I used for my code. I had also read that the maximum duty cycle is 85% on, which is why I scaled the pot value from 0 to 42.

          Necessary parts:
          1 – Potentiometer
          1 – Arduino Board (around $30)

          This code creates a PWM signal with 0-85% duty cycle and 50ms frequency on the MC 2100 treadmill motor controller

          int ledPin = 11; //this is the PWM signal out
          int pot = A0; //Potentiometer (connected from 5v+, A0, Grnd)
          int potValue = 0; //Tells Arduino there will be a # named potValue

          void setup()
          pinMode(ledPin, OUTPUT); //tells arduino pin 11 is output
          Serial.begin(9600); //arduino counts. only necessary if you want to pint (below)

          void loop() //the following cycle will repeat every 50ms
          potValue = analogRead(pot); //reads potentiometer value
          potValue = map(potValue,0,1023,0,42); //scales potValue to 0-42 (85% duty)
          digitalWrite(ledPin, HIGH); //turn duty on
          delay(potValue); //time duty is on
          digitalWrite(ledPin, LOW); //turn duty off
          delay(50 – potValue); //time duty is off (50 – on time)
          Serial.println(potValue); //not necessary. shows duty on computer
          The analog out pin (11, named ledPin) is connected to the blue wire, and the black wire is connected to the arduino’s ground. The arduino is powered by the red and black wires from the controller. I also found this wiring diagram of the controller:

  • jschoolie 10:07 pm on September 17, 2012 Permalink | Reply
    Tags: , , iso box   

    Iso Box V.1 pre-completion 

    I built this to isolate my speaker cabinet so I can play in smaller venues by miking my amp inside the box and running that to the sound board. It still needs some work though, and I need to finish the outer walls before putting it to use.


  • schoolie 12:36 pm on September 17, 2012 Permalink | Reply
    Tags: , , Miter Gear Repair   

    Repairing the cross-feed miter gear on an Atlas/Craftsman 12″ Lathe 

    I bought an old Atlas lathe on craigslist last year for $50. It was in need of a good cleaning and was missing a few parts, but all in all fairly sound. Joe made a replacement tailstock ram for it, and I’ve bought a new chuck and toolpost, and a few other bits. All in all it’s working pretty well after about six months of working on it off and on.

    One of the last features left to get working was the power cross feed. On this lathe, the cross feed is driven through a bevel gear set. The drive gear slides over the lead screw, and is supposed to be driven by a key that engages a slot in the lead screw. The bevel gears are ZAMAK castings, and the key appears to have worn away or broken years ago.

    Before Repair

    (Read the rest of this post…)

  • schoolie 8:03 am on September 9, 2012 Permalink | Reply
    Tags: , ,   

    Ben's birthday present 

    Here’s the video of the first thermite test. Molten iron!

    This was early August 2012. We bought the aluminum powder and iron oxide from Skylighter, an online fireworks supply company. We bought 2 pounds of aluminum, so there’s a whole lot more where this came from!

    • littleschoolie 8:34 am on September 9, 2012 Permalink | Reply

      The sheep definitely makes it… 😉 I saw the “Leg up” video in the related videos, you oughtta post that as well.

  • gumby3344 7:17 pm on September 8, 2012 Permalink | Reply
    Tags: 808 cams, aviation, bottle rockets, helicopters, remote control   

    Helicopters, Bottle Rockets, and Boredom 

    Flying and shooting bottle rockets from helicopters with my leprechaun neighbor, Ryan.

    • schoolie 10:48 pm on September 8, 2012 Permalink | Reply

      Cool! I wonder if you could attach a camera to a couple bottle rockets…

      • littleschoolie 11:24 pm on September 8, 2012 Permalink | Reply

        Synchronizing ignition would be an issue along with blast shielding. If I took one apart and replaced the battery with a button cell or something we might be able to pull off the weight, I dunno, have to see.

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