So I have wanted to do a stupid EV project for a while and a few months back I saw a Razor MX350 electric “dirtbike” at a tagsale for $25! The batteries were shot, wheels barely holding on, but it had a frame and that’s all I needed.
The plan is to replace the 250 watt motor with a 2700 watt RC plane motor I had laying around. I will be building a custom battery pack most likely using Vruzend battery caps, an equalsZero Brushless Rage motor driver, and some other BS to make this work. So far I have made a wooden mock-up of the motor mount and it fits. The steel mount should be ready in the next week or so and after that it’s all electronic from there. I’ll post updates as stuff gets added on.
Probably a little late but if you haven’t heard, the world’s greatest show and tell is going on THIS WEEKEND in Queens NY from the 22nd-23rd. I will be at the faire with some others from the UConn IREC team at the “Amateur Rocketry” booth.
Over the past few days I have been re-writing my own code for my touch slider project and I finally arrived at a point where it is running fairly well. All code and future updates on the Arduino code portion will be available on my github using the link below. There are still a few bugs to work out but at this point I have a code I feel is ready to publish. The biggest issue is the outputs will sometimes latch onto a direction. I have a fix for that which is fairly simple but I have not implemented it yet.
I decided to make the project open source and it is licensed under the MIT license. When I have a proper PCB design I will be publishing the BRD files and schematics for that.
The current method of testing the slider isn’t the prettiest, but it sure works well.
It has been about a year since my last attempt at building a functional touch slider that works with custom Project Diva controllers but its back! It was a combination of seeing a 18×24″ piece of single sided copper clad FR4 in my amazon recommended bar, not wanting to invest $1000 into developing a hobbyweight Combat Robot, and a new copper sensor layout idea that I saw on a datasheet.
I knew from my last “attempt” that a lot had to change. The three main things were to significantly shorted the traces from sensor pad to MPR121, less gap between sensor pads, and to zig-zag the sensors allowing for better contact on multiple pads while also increasing overall width. With these criteria in mind, I went to Inventor and whipped up a few sketches of different patterns and imported to CorelDraw. After filling in the bits that needed filling in, I set the whole file to inverse color and I was ready for the laser cutter. For anyone following along at home, this is the image to use if you want to attempt your own. If you have CorelDraw, I can give you the native file to import instead of using the JPEG below.
For anyone not familiar with making a PCB with a laser cutter, it is done by spraying the entire board with paint, and etching away the negative of your copper layout. After a little cleaning with rubbing alcohol, the whole board is etched in ferric chloride. For anyone following along at home, my laser settings on an Epilog 40W laser were speed 5% and power 10%. My next attempt will probably be 12-15% to remove a little more on those thin traces between the contacts, two were bridged after etching.
With the board etched, the last two steps are to acetone away the remaining paint, and to drill the holes
Not pictured is where I am currently. I drilled the holes and attached the first MPR121 breakout board and it is working fantastic with the first 12 sensor pads. the next step is to wire up the other four and try to get some working code which is always the hardest part for me.
I got some base code to work off of from Reddit user u/Fatso666 and modified it to work with all four sensors. Did a little cleanup and it’s working! I unplugged the middle four arrows for the time being to plug into the Arduino that is hiding underneath the controller and taped a box behind to hold up the slider but everything registers without issue. I will still be working to revise the code to operate smoother and more efficient. I may try to possibly add code for tracking LEDs up top just like the real cabinet but I don’t want to get ahead of myself just yet.
Also this means I have to build another controller being a 1:1 replica of the input face. DivaPRO? DivaUltimate?
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.
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.
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.