Barometer Bulb Blues

After a few weeks I finally got the remaining parts in and cast a smaller bulb for the first “full prototype”

As you can see, it still has work to be done. It “almost fits” (TM) and “almost works”. Unlike with the first prototype bulb, this version does not always register the hit. It could be the switch to a 3v3 8mhz board or the cheap eBay special BMP280 breakout boards. For now it’s off to the side as I came up with an idea for a full size Project Diva touch slider PCB that I will be making in the next week or two.

BaroButton prototype working.

A few weeks ago I had the idea of creating a light bulb that when shot with an airsoft or Nerf gun will turn off. The most difficult part of this project will be the pneumatic button but as if today I have my first prototype working.

The silicone dome was cast from Smooth On Dragon Skin 30 in a 3D printed PETG mould. I then laser cast a base and ring to sandwich the dome sealed and used some RTV sealant to help out a bit. Inside the dome is an Adafruit BMP280 barometric breakout board with all seven wires running to an Adafruit Feather. Some test code was written and when the dome is depressed, the red LED on the arduino shuts off and remains until it is reset.

Now that the prototype works, the next step is to put it into light bulb form factor. I will be using an eBay 5v 2A switching PSU to power the whole system. The board will be a purpose built board with a 3v3 logic ATMega328 running at 8MHz and a constant current LED driver for the 5W (or so) LED. The Barometric sensors will probably just be eBay specials as I can get them for under $1 soldered to a breakout and the raw BMP280 from Digikey is over $3 each. As I get parts in and work on the bulb form factor version I will make new posts detailing the progress.

1:10 Scale RC Rocket Trailer: Complete

After a few months of welding, grinding, cutting, and powder coating my mini trailer is finally complete. Well, I finished this about a month ago but I am just now getting around to posting about it.

Dog for scale.

     This project all started when Tom Cohen gave me a 1:9.4 scale Higgs Farm Rocket kit and I knew I had to make it just a little bit better. I designed the trailers basic shape in CAD using photographs of it as reference. The frame is welded from 1/2″ steel tubing and the tower arm is made from steel rods welded to shape. I used a linear actuator from Actuonix to raise and lower the tower. The rocket rides on a 10x10mm maker beam and micro rail buttons which are basically just nylon 2-56 pan head screws. The wheels and covers are 3D printed from HIPS plastic with rubber tires from my local hobby store. Finishing the build is a 1:10 scale RC Suzuki Jimny which does a decent job of pulling the trailer weighing three times as much.

The mini trailer at MDRAs Red Glare 2018 was well received with many people asking if the tower really lifts and taking videos of it doing so. The Higgs Rocket was launched on an E-30 composite motor which scooted a lot faster than I thought it would. Luckily a fellow rocketeer picked it up from the other side of the ditch saving me a long recovery walk.

Selling a 2007 Ninja 250 for $13,500: The Story of a Scammer

This tale is a warning to anyone selling on Craigslist as well as other similar sites. It not only applies to selling motorcycles but also any high ticket items. The following image is a FAKE check sent to me by a scammer. When selling online, cash is king.

Note: The name I gave to the scammer was false and the address given was different from the location of the motorcycle to prevent possible theft. I do not suggest giving any info to those who show signs of being a scammer.

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As many people who have sold on Craigslist before know, the majority of messages you will receive are less than legitimate. Unfortunately for those who are new to online selling, the red flags which are clear to many will go undetected to the less experienced. I received one such message and decided to enter the eye of the storm. I responded to one of these scammers and pretended to be someone interested in the offer made in the name of science.

The following messages are between me and a Craigslist scammer.

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This is what I will call the first contact. In this message the scammer will ask if the bike is still available. It was at this point that something was off as MOTORCYCLE and SALE were capitalized which seemed a bit strange. I responded letting him know it was available and received a second message soon after. At this point I knew it was a scam as I had a very detailed Craigslist post with price and condition including all the service I had performed on it in the past year. The scammer clearly had not read the post and likely got my phone number from an automated bot. Because I knew what he was going to tell me next I gave him a price almost an order of magnitude over the listed price, a whopping $13,500.

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He agrees. His next message is the meat of the scam and I will explain how it works. The scammer will send a fake check to you for a larger amount than the price you just gave. In my case I was sent a check for $16,550. The reasoning for the additional money is because you are responsible to pay the shippers in cash for your own bike to be stolen. Sometimes the scammer will also tell you that any money left over from the shipping costs is yours to keep. The result is you lose your bike and transport costs to the shippers which gets delivered right to the scammer.

Keep in mind that I said fake check. You will be mailed a check that looks very real and even passes the security features listed on the back of the check. The checks are often from real accounts so your bank will put the listed amount in your account and you will believe that you actually received the money. Reality sets in a week to a month later when the fraudulent check is discovered and the funds are removed and you find yourself in a possible lawsuit for passing a counterfeit check. Due to this very real possibility, I covered up the company name and all numbers on the check.

The conversation between the scammer and I went a bit longer and I gave him an address to send the check to. After a few days I saw an envelope addressed to the bogus name I gave him. After opening it up I saw the fairly well made fake.

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Strangely enough, it was sent from California which is quite a distance from the scammers 404 area code of Atlanta, Georgia. This may mean there is a team who orchestrates this or the scammer is using an app for sending messages.

So where does this leave me? I still have my bike and when the scammer asks for the address for bike pickup, I will be giving the address of the local police department. Will this stop the scammer? Not a chance as even if I were to find this one and get him arrested on felony charges for sending counterfeit checks through the USPS, the vast quantity of similar internet cretins will just fill in the void. The lesson to take away from this is that dealing in person with buyers and only accepting cash are major factors in preventing a situation like this. There are more variations of this scam and other types entirely such as the VIN check scam or a potential buyer going for a test ride and stealing the bike right there. Be cautious, look for the red flags, and if something seems too good to be true, it probably is.

Camera Shy: Flight report

After getting the decal applied and finishing touches complete, I flew a test flight with the new Raven 3 flight computer and an Aerotech G80 motor

The flight went well, however the tape holding the motor in let go instead of the shear pins resulting in a lawn dart from 300 meters, only to be saved by the main chute poping at 500 feet. The other problem was that I did not have enough recovery wadding which resulted in the parachute getting toasted.

Flight recorder data shows that it experienced approximately 140gs upon deploy at around 275mph. All damage has been repaired and it is ready for it’s maiden flight on the I1299 in Potter, ANY on October 28th.

The Worlds Smallest Project Diva Controller: The μDiva

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This latest addition to my growing collection of Project Diva: Future Tone controllers is a 1:4 scale version of the full arcade layout. At its heart is a Brook PS3/PS4 fighting board and four Seimitsu PS-14-DN 24mm buttons. Housed inside of a laser cut ABS case provides durability and style. In addition, this iteration features a brand new input method by means a capacitive touch sensor.

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The touch pad is manufactured by Brook and has approximately the same dimensions as the Dual Shock 4 touch pad. The USB cable is detachable with a micro-XLR 4 pin connector and tech-flex covering for protection. While this is a finished prototype, the rough ABS edges are still far from perfect and will likely use white acrylic in the final version.

As for now, the controller is not for sale and the design will receive a few more iterations to increase internal space, strength, and ease of assembly. After these updates, the files will likely be uploaded to Instructables along with full assembly instructions. If I do manufacture finished controllers if anyone actually wants one of these tiny (but still fully usable) controllers, estimated price will be around $199 USD.

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Laser Cutting ABS: Tips and Tricks

Laser cutting ABS is possible, however, it is not really safe to breathe and the cuts are not too clean. The following is all based off using an Epilog Helix 40 watt laser with air assist and a fume extractor. Air assist and a fume extractor are essential for ABS.

First, some background on ABS. It’s full name is Acrylonitrile butadiene styrene. It has a relatively low melting point, flexibility, and strength which makes it great for 3D printing, vaccuum forming, injection molding. These same properties make it a pain on the laser as it results in yellow/rough edges and warping which moves the work piece out of focus. The other problem is when melted, ABS outgasses HYDROGEN CYANIDE which is not good to breathe so make sure you have your fume extractor set up and turned on.

To counter this I have found the following tips and tricks to minimize problems.

  • Test cut a piece of your material to calibrate your settings. On white ABS for vector cuts I use 100% power, 8% speed, and 5000hz frequency.
  • Use blue tape on both sides, this prevents most of the melting fro. Ruining the edges and the smoke from damaging the color
  • If your work piece is large enough, use hard drives or other objects to weigh down your sheet to counter warping
  • Use air assist and if possible, use a nitrogen air assist to prevent flame-ups.
  • Wash your parts with soap and water after cutting to remove some of the smell

It is a tricky material and will require some fine tuning but this will definitely get you started.