Last weekend I got the suspension reinstalled onto the chassis and installed the pedals.
All that is left to do is install the brake lines and the electrical system. I don’t think this will take more than a day, but next week is finals week and I feel I must repress my desire to just finish it.
I also worked on the cluster. I managed to get a promising circuit together for the backlight controller. All that is left to do on that circuit is to solve for the capacitor and resistor values that will give me a 20% to 100% duty cycle between 18kHz and 22kHz frequency range (As required by the datasheet). I haven’t developed a circuit board yet as I still need to make one more circuit. The engine computer powers the sparks plugs. I haven’t placed an oscilloscope on it yet, but I imagine it is using a square wave to charge the plug and then discharge it, but due to the plug being a giant transformer it is probably going to have voltage spikes as well. I need to develop a circuit that can take this signal and feed it into the computer for the tachometer.
Now that I have all the systems on the trike worked out, it is time to tear it apart, touch up all the metal, fully weld everything, paint it, and do final assembly.
First, I want to cover some of the items I left out before.
The seat was designed to hold a driver and a passenger between the 38 inch width frame. Originally, this vehicle was designed to be a single person vehicle, but I decided to make it a two person vehicle after the chassis was completed. It is possible for two average-sized persons to fit in this seat despite it being a tight squeeze. The seat is made from 0.25″ plywood with angle aluminum holding the corners together. The wood was bolted to the aluminum. The plywood was then covered in 2″ foam. A steel box was developed and bolted into the center. This steel box was designed to hold the lap portion of the seat belt for both the driver and passenger. It bolts directly to the vehicle chassis independent of the wooden frame. My mom then did an amazing job making a cover for it out of pleather (vinyl leather substitute). Thanks mom!
I really wanted to go all out on the wiring. My idea was to run nothing but can-bus and power to all the modules. This would require making microcontrollers for all the modules (engine, headlights, taillights, cluster), but I’m under a time constraint to get this vehicle done by the end of the semester and present the project as an undergraduate study. Some items had to be scaled back. For the time being, this wiring harness is a simple logic of relays and a turn signal module.
After all the welding, I took a circular wire brush in a drill and took off some of the larger bits of rust. The rest of the rust was treated with PUR15. This leaves a zinc coating on the metal. That is why the chassis has a white appearance. I also filled in the seams with paintable seam sealer.
This was followed up with a primer. It started raining right after I got it painted. I had to shove it in the garage before I could get a picture.
Finally, I sprayed it with satin black. I did this using Rustoleum Oil-based paint thinned with acetone before being put into a spray gun. I don’t know for sure, but I assume this paint is similar to what Rustoleum puts in their rattle cans. The idea being even once this project is done, I may want to add some stuff to the chassis. It would be nice to grind of a small area of paint, weld on my new item, and rattle can the small area. Plus this paint can be had at the hardware store for <$10 a quart. I don’t know how well this paint will hold up to the sun or abrasion from normal use, but I will report back on this.
After all this, I’ve began final assembly as well as making sure all the small brackets are painted. I did this with rattle cans. For final assembly, I made sure everything is secured, welded properly, torqued properly, and do an inspection before attaching to the chassis. This is a slow process and so far I haven’t noticed anything wrong. It would be very incontinent to have to grind paint off and reweld something, but this is a small price to pay compared to having a part fail while going 70mph. In most modern vehicles 70mph doesn’t seem like much, but this is 102.7ft/sec!!! Not only is this a safety concern, but to lose two years of work to a simple mistake would be devastating.
This brings everything up-to-date with what I have done as of today (April 17, 2018), I am currently working on building the cluster. Here is a teaser of the cluster.
The cluster three boards seen here are the Raspberry Pi model B+, an HDMI-LCD Controller, and a buck converter (regulator). This is all designed to be mounted inside of the water proof box. There is also a GPS module. The idea is that the GPS module will provide speed over serial communication that can then be displayed on the screen. It is a quick and cheap solution (Other than the box, I already owned all the parts.) to make a speedometer. A speedometer is legally required for the vehicle to be road legal. The LCD screen is rated for 690nits. This is bright enough to be visible in direct sunlight. This is also too bright for night time visibility. My current project for this is to build a custom circuit board to control the brightness of the backlight based on the ambient lighting around. I would also like for the computer to have control over the backlight so that it can be turned on and off via software. This is my “quick and dirty” solution to hiding the on-screen display that shows up when the LCD is first turned on and the boot process of the computer.
The suspension was completely redone using a transverse leaf for the spring and two Gabriel air shocks for the shocks. Below is a picture of the leaf spring being fitted into place. This was done to see how the vehicle will sit and to adjust the length of the hangers from the leaf spring.
Finally, the test drive video. The test drive went well, the suspension worked great! There are some carburetor issues that I need to work out as it appears to be running lean.