So what do you get when you bind the profession of engineering & the passion of design in one big pot with some added spice, parsley, & a pinch of craziness? For starters, maybe a whack of creating or prototyping contraptions.

I enjoy prototyping new ideas which come to mind, whether it's small personal projects or large ones requiring the demands of a dedicated team of specialists to get it done, there are endless possibilities to what you can do, let be the fun in tackling challenges. Here are a list of inventions I particular fond of and managed to compile online.

The Budway, aka the Budget Segway is a poor man's alternative to the highly advanced commercial Segway PT with few extra perks. Firstly, the unit is simpler, lighter and more compact with smaller wheels. The aluminum wheel unit assembly is foldable, together with the retractable handlebar which both locks with rod pins, allowing it to be compacted into the size of about 2 folded skate scooters which can be kept in a backpack or hand carried up a bus or train without much considerable bulk. This prototype costs about $2500 to build.

A gyroscope sensor and accelerometer monitor angle or tilt which inputs through Kalman filters to a HC11 microcontroller (a niffy handy board from MIT). Through about 200 lines of code, it computes the resulting pulse width modulation signals to control the supply of electrical power to the left and right electric motors to keep it balanced. It works by driving the motors to counter balance the unit. The logic is simple- take it like balancing a pencil on your finger- you need to move your finger in the direction which the pencil tends to fall towards. So in turn, on the Budway you go forward by leaning forward and stop by leaning back. Steering the unit involves offsetting the left or right PWM outputs by the potentiometer tilt angle of the handlebar.

It runs on standard electric brushless DC wheelchair motors fuelled by Nickel metal hydride batteries through a custom charge controller which regulates the discharge and re-generative charging when the Budway is going downhill. It manages a 20kmph max speed.

Safety features includes an auto kill switch on the handle bar, an occupant "On" sensor as well as a fall shutdown when the unit falls either forward or backwards beyond 45 degrees, so it won't go careening away on it's own. Future enhancement plans include experimenting with Li-ion laptop batteries and adding a Bluetooth module allowing the Budway to be remote controlled by a paired laptop or mobile phone.

The Radicurl, (also known to some as the "radical") Motion Simulator was one of my better documented creations with photos, also partially because it was featured in quite a number of engineering publications and on national TV as well. Built from scratch by a team of 3 experts (one in fabrication, electronics and myself in concept, materials and design) over a span of 14 weeks, the simulator is essentially a PC based 4-axis gaming motion simulator actuated by pneumatics. It runs mainly racing and flight games.

The super structure itself is fabricated out of mild steel, the pivots on the pitch and roll axis are sitting on heavy duty NTN bearings actuated by counter-acting pneumatic cylinders through 5/3 middle closed Festo Maxi valves fuelled by an external air compressor. A dedicated Pentium class CPU runs the graphic intensive games, while another ethernet networked PC extracts gaming related data such as velocity, G-forces etc and computes them into calibrated numerical offsets on the required axis. A Velleman USB controller card sends the PVM outputs to a relay which in turn fire the valve's solenoids.

Safety features includes a kill plunger each for the operator and driver and an independent pneumatic platform stabilizer for boarding/disembarking. Few additional extras will include ultra cool LED lighting, a bright blue Spacro racing seat, 22" LCD monitor and 5.1 surround sound, pneumatic-actuated steering wheel adjust. Cup holder not included.

Read more about the simulator and team Radicurl in my blog (Includes multimedia content).

Could it be a laser ray gun? Or a light saber? More details after I am done with all the patent stuff.
Implemented on a conventional mountain bike, this enhancement serve as a riding aid for mountain bikers particular for cruising or load lightening when going up-hill on low gear. This bike is rather simple in nature, comprising of a simple Nickel metal hydride battery mounted on a rail above the rear wheel and connected to a brushless DC motor sourced from a used electric wheelchair. The motor is connected directly to the drive chain and the pedal gear which in turns assists the rear driving wheel, preserving the bike's rear gearing system.

The drive is built simple to withstand shocks and works only on discharge with no regenerative abilities when going downhill (after all, the chain won't be rotating when going downhill, unless the motor is coupled directly to the rear axle). The drive is activated via a flip switch mounted at the bike handlebar.

Built during my secondary school days, this project did not go further into development given the restriction of motorized vehicles on pedestrians walkways and parks in Singapore, as so there's no feasible way the unit could be tested, let be used legally even when it's completed.

I've always wanted to try different variants with a compressed air engine which I can use to drive a bike in similar, let be ported to a car chassis or ATV, but scrapped due to similar reasons. Singapore is just not an invention nation, we can't just build any of these and test them out on the streets due to the many restrictions in place.

This is essentially a black and white line art duplicator built using Lego parts, written in C and running on the Mindstorms RCX 1.0 brick (which is essentially an 8-Bit collision detector Renesas H8/300 micro-CPU with 32KB of RAM). It's a big improvement of the rather basic plotter we get on the Mindstorms inventor pack.

The A4 sized printer has 2 trays, one on top of each other- it traces lines from a drawing on the top tray using a light sensor and plots them concurrently on the lower tray on another blank piece of paper. The plotter runs draws on the X and Z axes, while the drawing pen moves up and down on the Y axis courtesy of a pneumatic cylinder powered by the RCX's third motor output. In manual mode, you can use it as a giant etch-a-sketch.

Is that all? Well, I've never had the luxury of documenting every single thing I build, most of them are just mini DIY projects I made mostly during my free time and put together with remaining parts from my previous inventions. Some few significant ones I've made during my primary-secondary school days includes:

Pathfinder transporter

This robot serves much as a personal item transporter or PIT for short, it's essentially a small Tupperware container mounted on wheels programmed to navigate between rooms in my home to deliver items. Say, pass the book or phone to sis's room? It is skid-steered and can detect obstacles, dogs, people around the house using a pair of ultrasonic sensors. The robot is programmed to pace each journey, so it can always retrace back any new route it travelled back to my room.

Spybot

A remote controlled tracked vehicle I made from parts from a dismembered toy bulldozer, a 4 channel remote control relay and two 3V Tamiya car motors savaged from my previous inventions. It's all body encompassing caterpillar threads makes it all-terrain, flip-resistant and can be driven on either side. The fun fact is that it have an independently powered CMOS camera on board which feeds live video wirelessly to a TFT screen which can be mounted on the remote controller, so you can send it out of the range of sight for some fun exploration or surveillance around the compound, or simply just bugging the dog in the backyard.

Lego VHS and Mini-DV rewinder.

A few of my other simpler but rather practical inventions I made when I was a kid. Lego makes up pretty much the whole thing, the tape deck, loader. A geared 3V motor linking 2 drive spindles via a pulley spins the tape reels in unison. The drive motor is kept at a high gear ratio for maximum speed and low torque so that the tape won't break off the reel when the rewind hits the end. A light sensor positioned over the tape reel window checks the contrast between the black tape and white reel and stops the motor when the rewind process is complete.

Note: All items are not for sale.