Carbot Lite

Carbot Lite was built on commission with the idea of being a smaller carbot than my other versions. This version has only two suction cups, and was designed to not follow the normal radial style of the others. It has 3 4700uF capacitors in parallel, with a single 43x34mm Solar Cell providing 5V@ 40mA.

I typically use the MCP-112 450E for my solar engines, but I was concerned that the 4.7V trigger point would be too close to the max voltage output of the solar panel, so I opted for the 315E variant which triggers at 3.08V. This would result in less power to the motor, so I would have to make sure the spinner was light enough to get a few spins in. I also had to be careful to make sure the spinner was balanced, as this bot would be stuck to a window, and gravity would take effect.

The brass wire used as the frame is 12 gauge round half-hard brass wire. It was shipped coiled. So I had to find a way to straighten it out as best I could. I grew tired of using jumbo paper clips, which were actually steel and didn't solder as well as I wanted. Luckily I found this video on youtube which provided an elegant solution to my problem!

Carbot 2

The creatively titled Carbot 2 is born! This bot uses the same Miller Solar Engine circuit as the previous Carbot, but some changes were made. I wired six 1V 30mA solar panels in series to produce 6V @ 30mA. A 2.2uF timing capacitor was used to give it adaquate spinning time, as the hefty spinner required it! It was constructed from brass rod and large plastic beads. The sun reflects off them quite nicely.

Originally I was planning on using three 4700uF storage capacitors in series to achieve 14,100 uF, but I only had two! I was worried that two would not be enough capacitance to spin this bulky spinner, so I opted to use what I had lying around: three .3F 2.7V supercapacitors in series, which equals .1F @ 8.1V. In this configuration, the bot takes about 30 seconds of charging in full sunlight before it begins to spin every few seconds.

The solar panels are held together with hot glue and jumbo paperclips, which is connected to the main chassis and motor by E6000 and tension. I would have preferred to build this bot with more toughness, but I ran out of time, as it was a Christmas gift. Also, as a stationary spinner, it will not see too much action!

As 131 triggers are hard to come by these days, i instead used the MCP112 equivalent drop-in IC (MCP112-450E) which triggers at 4.38V. The higher trigger voltage points gives the motor enough juice to get spinning.

Tornadobot

This little guy hangs from a chain suspended from the rear view mirror in my car. Utilizing two 24x22mm solar cells in series, Tornadobot builds charge then throws all its power into the propellor which is connected to the chain on either side. The result is quite a jolt, but eventually settles into a controlled spin. I have recently re-balanced it so it doesn't bounce around as much. It has a 0.047F supercap to provide the bulk of the power, with a supplemental 4700uF cap in parallel. I was initially afraid the internal resistance of the super capacitor (I think ~200 Ohms) would be too high for this motor, so I added the extra capacitor to aid in the initial burst, but also to aid in balancing this bot.

The propellor is attached to the motor shaft with Krazy glue (cyanoacrylate) and heat shrink. I actually use Krazy glue quite often in my bots. It gives a very strong bond regardless of which materials I am bonding.

UPDATE:
So after a few years the motor started acting funky. I actually got a bit of hot glue inside of it when I first was building this bot, and I think it finally took its toll. So I updated this bot with a 600 RPM N20 gear motor. It's activation is much more calm! This will improve the bot's lifespan by putting less strain on the motor and the rest of the parts by making it less likely to fly off the chain and break its self.

Carbot

Carbot (creative name, I know) was designed to be a simple miller engine that sticks to the inside of your car's windshield. With its outward facing solar panel, it will build up charge on its three 5600uF capacitors and release that energy in one big burst on the bulky DC motor in the center. The load on its shaft is a bit heavy (the LEDs on the propeller are non-functional), so the solar engine needs a decent amount of charge to build any momentum. The inspiration for this bot was taken from the now defunct Jim's BEAM Page. Jim made an impact with his special attention to the Aesthetics part of BEAM. What remains of his designs can be viewed in very poor resolution at beam-online.com