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Posted by Jack Crossfire | Feb 07, 2016 @ 12:29 AM | 2,597 Views
Its 2nd revival. This time, the hose came loose. Put in a better power switch & new hose clamp. The 1st time, it was a failed conversion to try to make a vacuum. It doubled in price in its 15 year history. Not quite as fast as inflation, but always impressive to keep something going.
Posted by Jack Crossfire | Feb 06, 2016 @ 01:52 PM | 2,414 Views
Stadium run timelapse 2 (4 min 6 sec)

A few more hot glue sticks & the camera worked quite well. The camera needs leveling. The shirt could slide in without removing the camera. It remaned quite drivable with shirt & camera. It became almost the perfect running system or the aid station on wheels 1st envisioned. For a short time, no-one else in the world has anything like it, but rest assured, the aid station on wheels is going to be everywhere, someone is going to make billions off of it, buy out all the apartment complexes & evict us.
Posted by Jack Crossfire | Jan 31, 2016 @ 07:38 PM | 2,963 Views
A new cargo container made out of 15 year old corrugated plastic was finished. The plastic dated from a time cheap letter trays were sold at Target. They definitely don't sell stuff that cheap anymore & the last plastic became quite brittle from 15 years exposed to UV light, so it might not last.

The electronics were made more compact & enclosed in a bigger sheet of plastic. There was no way to put the electronics on top. Used transparency from circuit board etching ended up quite useful in waterproofing the electronics. It could be stapled into box shapes for the radios & hot glued on the wood for the mane computer. Hot glue was quite tenacious when used to clamp transparency down but was quite worthless when adhering transparency to itself.

At minimum, the waterproofing should prevent more droplets from hitting the electronics, but would be no match against submersion or heavy rain.

Reglued the headlights & made them always on. A switch was considered not reliable enough in the rain & the overall current usage was low enough. Bluetooth headlight control remaned too much of a pain compared to a switch.

The cargo container was hot glued on. Using hot glue to adhere the plastic to wood seemed good enough, despite hot glue not adhering to corrugated plastic alone. It may still be bolted on, but this wouldn't be as rigid.

Retaped the battery & ESC in. Gave the ESC more tape to try to slow the water penetration.

In a 6.9 mile range test with the cargo empty, it used 1443mAh or 209mAh/mile. It would now probably go 18 miles. A coulomb counting charger at the day job would allow testing the range with cargo. Steering was already quite top heavy with no cargo.
Posted by Jack Crossfire | Jan 28, 2016 @ 10:57 PM | 2,650 Views
Stiffened the suspension with all the supplied C rings. That provided just enough stiffening to consider a payload. Built a cargo container out of cardboard & hot glued it on. Carrying a shirt, the system worked well enough to justify building something waterproof. Cardboard was much lighter than the lightest plastic option: a $10 shower enclosure.

With the shirt, sharp turns barely managed to not flip. Wheels pressed all the way up when turning. Corrugated plastic would be the next idea.

The permanent design involves having the cargo container on spacers, bolting the cargo container on, mounting electronics under it, on top of the vehicle. Yet another idea involves making the container permanent & having the electronics on the side. Only the gyro would have to be flat. The permanent design would allow cutouts for the wheels. The mockup was essentially permanent & didn't show any problems.

It has to be finished in 2 days.
Posted by Jack Crossfire | Jan 24, 2016 @ 10:34 PM | 2,777 Views
The 2 vehicles went 47 miles & the human threw down another 16 alone in the last 7 days. It takes a lot of sleep for a human to run that far. A human who can run that far outruns the robots quite often. Increased mileage has led to increased problems with the vehicles. Compare to 2 years ago when it was a buster to keep up with the G-buggy set to 9 minutes/mile. Now the robots more often have dead batteries & failed electronics before the human.

This year is much slower than last year, but the focus is on endurance more than speed. Robotic pacing has been key to longer distances, by preventing the human from going too fast in the long runs & making the intervals faster.

Slow steering buttons were destroyed in yesterday's rainstorm. Yet another reason for a removable steering pad which can be attached to both sides for dual handed operation. Had a few flips. Need to find throttle settings which prevent flips. Microcontroller had no problems after drying out. Water was the problem & neither conformal coating nor packing tape did the job.

The next step will be a transparent garbage bag covering the entire vehicle. Quite an astounding increase in rain from the last 3 years, yet it's still below average.

Carrying 44oz of cargo greatly increased the battery usage of the lunchbox. 6 miles with the last 3 carrying 44oz cargo took 3672mAh. The old battery is down to 4300mAh, but it might have less capacity when charged at 3A.

Rain continues to cause...Continue Reading
Posted by Jack Crossfire | Jan 23, 2016 @ 03:00 PM | 3,020 Views
So after driving the ECX Ruckus 58 miles in the city, it became clear that the lunchbox had a lot of advantages. Manely, being able to haul a shirt is huge. Being able to have a camera far above the pavement is huge. These things weren't apparent when the ECX Ruckus arrived. Cargo hauling wasn't even a concept.

A 2nd lunchbox would have been the same cost as the Ruckus. The mane problem is it would have a much harder time navigating the city. The narrow Bryant sidewalk & the mobs on the waterfront would be impassible. It would only be useful in 1 small area.

A narrow yet tall vehicle is a better match. A hoverboard is too wide. Gyroscopically stabilized vehicles require constant motion. A small vehicle stabilized by a quad copter on a stick might do it. The idea appeared before, but not with the practical application of cargo & camera elevation. It's really the only way to get eye level video. Eye level video might aid autonomous navigation.

The quad copter vehicle wouldn't lift its own weight, extending battery life. It would have to exert only horizontal force on the stick. High wind makes it impossible for a purely attitude stabilizing vehicle to do the job. 4 narrow diameter fans pointing sideways would always be spinning, exerting various amounts of thrust based on the angle of the stick. Fan diameter would depend on wind resistance. The fans would be at 4 different elevations, to allow air intake.

There are reversible props, simplifying the problem.


The mane problem is the fans would be spinning at eye level in mobs. It would take quite a hefty screen or sphere enclosure. It would still blow quite a bit at their faces.
Posted by Jack Crossfire | Jan 17, 2016 @ 06:01 PM | 3,550 Views
With the ECX Ruckus permanently stationed in the city, it made videos.

pier39 via ECX Ruckus (3 min 9 sec)

& more videos

Stadium run via ECX Ruckus (3 min 32 sec)
...Continue Reading
Posted by Jack Crossfire | Jan 17, 2016 @ 05:45 PM | 3,191 Views
After 15 years of using 2 cordless keyboards & 1 cordless mouse, finally switched back to an old fashioned corded setup. The constant battery deaths would occur in the least timely moments. The radio integrity was random. The range wasn't long enough to truly be cordless. The mouse speed would change randomly, after changing batteries. The return to corded input is like returning to 1999, an easier time. It always worked, but there was 1 problem.

The pointer speed for PS2 mice always worked in Linux. For USB mice, it never worked. xset never worked as documented. Always stuck with a 15 year old mouse with a PS2 adapter, even after its scroll wheel stopped working & it randomly jumped around on a new mouse pad.

Linux has gone now through a dozen attempts to control pointer speed for USB mice, none of which have worked. They've tried changing xset, xinput, gnome-mouse-properties, gpointing-device-settings, xorg.conf, 50-mouse-acceleration.conf. The only foolproof way to configure the mouse has been recompiling the kernel. This too migrated from a change in drivers/input/mousedev.c to drivers/input/input.c several years ago. After years of editing mousedev.c or just using a USB -> PS2 adapter to force it to use the old PS2 driver, here is the change to input.c to slow down the mouse:


static void input_handle_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)


#define DOWNSAMPLE_N 100
#define DOWNSAMPLE_D 400
static int x_accum = 0, y_accum = 0;

Then after the switch statement:

case EV_REL:


if(code == 0)
x_accum += value * DOWNSAMPLE_N;
value = x_accum / DOWNSAMPLE_D;
x_accum -= value * DOWNSAMPLE_D;
if(code == 1)
y_accum += value * DOWNSAMPLE_N;
value = y_accum / DOWNSAMPLE_D;
y_accum -= value * DOWNSAMPLE_D;
Posted by Jack Crossfire | Jan 10, 2016 @ 02:51 PM | 2,855 Views

The servos showed identical speed on the slow mo cam. Steering oscillation was down to the servo saver. With no desire to break another servo, decided a better solution was to stiffen the suspension. It took the whole day to add 1/4" wood pieces to shorten the springs. The wood needed grease to get the suspension moving. The stiffer suspension greatly improved payload handling, so it was a worthy alternative to finding the cause of the oscillation. It may one day work with the DSLR.

Drove home with another epic payload. This one flipped over a few times. The battery died .5 miles from home, after only 1 mile with the payload. Had to run back with a new battery, but forgot the remote control. Couldn't drive it manually. The payload made it too unstable to drive without the computer.
Posted by Jack Crossfire | Jan 09, 2016 @ 03:37 PM | 3,164 Views
Canon EF 50mm mechanism (1 min 34 sec)

So after powering up the lens with a minimum of components, the motor turned briefly then stalled again. After manually turning it, it turned more consistently. It never stalled again.

The internet can't agree on what type of motor it is & might have confused it long ago with the stepper motor in the F1.8 or what they term as a "micro motor". The motor impedances are over 300k ohms. Steppers have much lower impedances. The motor looks like the other ultrasonic motor documented on the internet. Canon would get sued for printing USM on it if it was a stepper. So rest assured, it's a USM.

The only other teardown showing any detail of a USM motor was


Its wire bundle went to a soldered point which failed. The 50mm's wire bundle went straight in the motor with no soldering.

Based on the scarce documentation, USM motors work more like human muscles than what's marketed as muscle wire. They contain thousands of tiny ratchets which move the payload. In the lens, the tiny ratchets are on the end of a large piston shaped thing. Most of the volume of the motor is a pancake of ceramic & metal alloys dedicated to just generating the vibrations. Only the very end of the pancake converts the vibrations to motion.

Because the tiny ratchets are always engaged with the payload, the motor has very high torque. Turning the stiff lens...Continue Reading
Posted by Jack Crossfire | Jan 08, 2016 @ 10:33 PM | 3,117 Views
So someone at the Goog some time ago introduced an algorithm which finds related channels to your gootube channel, probably based on browsing history of your viewers. To this day, computers can't recognize similarities in video content, only the valuation of ages old click counting has been increased to prevent a recession.

It popped up Casey Neistad some time ago, but never paid attention, figuring he was another weirdo who subscribes to the heroineworshipper channel. In fact, the concept of subscribing to a channel is still a bit offputting. Why couldn't they call it following or favoriting? How many parking spaces on 237 were filled to come to this decision?

It turned out he was one of the 1st reviewers of the hoverboard, previously was the Twit photo guest who was sponsored by gopro, a very well known videographer who never finished highschool, & lives in a huge 9 figure apartment in Manhattan.

Neistad videos are boring as batshit, but the technical quality is always spot on. Focus is always sharp. Editing is perfectly timed. Lighting is always bright. It's an enormous investment to make daily videos that well produced.

Sometimes in the drivel, there is something you've never seen before. Sometimes he has a novel solution to a common problem, like getting a hoverboard up a curb. The most novel visual at this time is seeing him talking to a camera while riding an electric skateboard. There used to be very pooly lit drive time rants from Dave. Then...Continue Reading
Posted by Jack Crossfire | Jan 08, 2016 @ 10:13 PM | 3,071 Views
After 8 years & hardly any use, the mighty 50mm died. Its autofocus died, while everything else still worked. The focus ring still moved, but the motor was dead. The internet abounds with failed autofocus tales, manely emphasizing broken mechanics. The gears break. The cylinder gets bent. Regarding the motor, the internet is silent. The motors are accepted to be without failures in the 30 years they've been around.

It might be good enough without autofocus to live with. In the days when foot transportation abounds, the normal lens camera of choice has been the phone. The DSLR is rarely used for anything. There's hardly any need for a 50mm lens except for the irrationality of a camera which can't take normal photos.

The only smoking gun is the motor is very hard to turn. It could never turn on its own unless it had a very tiny planetary gear in the motor casing. The 50mm f1.4 only arrived because it was the old man's lens. A better investment would be something lighter like the f1.8 or cheap wide zoom because 50mm is never used....Continue Reading
Posted by Jack Crossfire | Jan 03, 2016 @ 06:49 PM | 3,662 Views
Another holy grail in robotics is the ability to transport a DSLR. Unfortunately, the 1st experiment in this took it on trails, which failed miserably. On pavement, the vehicle was barely manageable. It had a constant steering oscillation, either due to the top heavy payload, the padding, or the Futaba servo setting up a sympathetic oscillation with the gyro heading. No amount of D or P gain made a difference.

Suspect harder suspension would make a big difference for these payloads. The wheelie bar was useless at preventing backflips.

Once on the trail, backflipping during the ascent abounded. Wheel hubs slipped inside the tires. Despite another dry December, the trail found a way to be packed with mud. As altitude increased, the mud became impassible. Walked with the lunchbox over most of it. Finally, the battery died after only 3.6 miles.

Driving a DSLR up this trail will never happen, because of the limited battery range. It might happen with the gopro, when dry. Driving a DSLR on the usual paved trail might happen with stiffer suspension.
Posted by Jack Crossfire | Jan 01, 2016 @ 05:12 PM | 4,470 Views
These Tower Hobby servos date back to the DVD robot of long ago. They were $6 in those days, but should have held up. It went hundreds of miles, then snapped during a mild crash after 1 mile. There are no metal gears for standard servos. Now going through all the Futaba servos in the apartment until they need new gears. The Hitec servos won't fit in the lunchbox's servo saver. Only Futaba & generic Towers will.

The trick with servos is the screw needs to go down past the case. That should transfer the load from the screw to the case, rather than from the screw to the gear to the case. Unfortunately, servo horn screws are yet another extremely rare hobby screw size with no more local shop. It would be more effective to eliminate the "servo saver" so the lone existing screw from 1988 can reach far enough.

After some grinding & 2 stripped screws, managed to get a custom horn loosely fitting where the servo saver went. The screws would never be a perfect fit. These servos arrived from China with only the Futaba S3003 sticker but nothing else matching the photos, no screws or attachments. Only stray Sanwa mounting screws & Sanwa horns from 1988 fit.

The screws are 1.6mm inner diameter, 2.2mm outer diameter, at least 9.5mm long, 0.825mm thread spacing.

After test driving in manual mode, it was time to drill out the Chinese gear & use a standard screw size to get the steering horn flush. It drifted quite a bit.
Posted by Jack Crossfire | Dec 31, 2015 @ 02:49 AM | 5,502 Views
A week after XMas, the mighty Team Associated 1/18 scale 14T pinion & 10T pinion arrived. Installed the 14T & experienced no change in efficiency compared to the plastic 16T. The plastic with heatshrink & glue showed no signs of coming off, so it might have been good enough. The 14T was cheap enough to not be worth the trouble of using the 16T. The change in efficiency was insignificant enough to not bother with the 10T.

What did show signs of improvement was tuning the steering to use more damping. The steering on the Ruckus oscillated quite a bit without a damping constant. Once the damping was jacked up, it drove straighter & power usage dropped from 230mAh/mile to 200mAh/mile on 1 test drive. The best explanation was the brushed servo took a lot of power to oscillate. It was a case of making a big difference in power usage by merely changing a software parameter.
Posted by Jack Crossfire | Dec 27, 2015 @ 09:23 PM | 3,225 Views
Hauled 2 batteries to do 10 miles + 3 miles with cargo. Decided to press to 13 miles in the end without stopping to pick up cargo. Massive discounts at Target meant not running home, but driving some cargo at 13 min/mile & carrying the rest for another 1.4 miles. Didn't have any flips. Hauling 2 batteries, the 1st battery died after 11.5 miles & took 4430mAh, so a slight reduction in range from 12 miles with no cargo.
The 2nd battery took 2300mAh to go 3 miles on account of cargo.

The next challenge would be hauling a DSLR 20 miles, but the mileage will probably be devoted to 12 mile grocery hauls for some time. Cold weather is unsticking hot glue everywhere.
Posted by Jack Crossfire | Dec 27, 2015 @ 03:05 AM | 3,764 Views
Expanding the cargo capacity began with a container that was too small to reach all the mounting holes. Even if it was expanded as originally planned, it would interfere with the radio, so the easiest solution was aluminum extender rods. They probably weighed as much as any attempt to expand the container.

The plastic container was trimmed & lights installed. A common string proved effective at securing a test payload, though hard to get off.

The 1st drive was 3 miles to walmart & 3 miles back with the maximum payload at 6 - 6.66mph. It backflipped when starting, so the string had to be undone & the payload had to be shifted over the front wheels. Don't think the wheelie bar would help because the objective is to keep the payload from falling out. Didn't try any sharp turns at speed. It was pretty unstable. It took 3541mAh to go 6.4 miles, so quite an uptick with the payload.
Posted by Jack Crossfire | Dec 25, 2015 @ 06:25 PM | 3,534 Views
The answer is no. Self balancing hoverboards don't really self balance or hover & they're extremely rare except by 1 guy on 2nd street. The range goes up, every time they're advertised, 1st 5 miles, then 10 miles, then 20 miles. Like most breakthroughs in the economic boom, they're not real. There's no information on how they work & no reviews by anyone who isn't a reseller, but the advertisements reveal some clues. Sellers are careful to place them upright on the ground to appear self balancing, but sometimes tip them over to show the battery indicator. There are no closeups of the electronics & no-one has any idea how they work.

The user must actively shift on top of the thing to stay balanced. The user presses 2 buttons on the foot rest to activate the motor. Pressing 1 button causes it to go forward until the acceleration is straight down. Pressing the other button causes it to go backward. Judging from what look like I2C lines on a blurry photo, there's an MPU6000 on each footrest, so they do sense true tilt angle.

They're 1 of the growing number of things for which no-one has ever made a firmware hack because no-one knows how. The 1st step in using 1 for hauling cargo is making it balance itself. This seems possible with the existing hardware. They only omitted it because it probably was easier to control if the user had to press a button to activate the motors & specify the direction.

Self balancing boards don't stay still if the...Continue Reading
Posted by Jack Crossfire | Dec 24, 2015 @ 11:47 PM | 3,105 Views
The lunchbox had some mounting holes in a more convenient place that would allow a larger payload. Rigged a quick cargo platform with headlights out of cardboard.

Hauled 1 qt of egg nog back, proving the lunchbox's ability to move significant cargo. Battery died .75 miles from home, after going 10.25 miles at 6mph. It only made 4.75 miles with the cargo. It still worked in 45F, but the voltage dropped all the way down to 5V because unlike the analog gyro of old, the MPU6000 needs only 3.3V. Didn't have any flipping issues. Helas, duct tape didn't stick to the payload, allowing it to shift forward onto the front wheels. Payload on the front wheels is very inefficient.

A tupperware with partitions would work better & allow more cargo than a flat piece. It needs only mounting points for the bolts & 2 holes for the shock absorbers. Tupperware with holes for string would keep the heaviest pieces over the back wheels.

The largest payloads of interest:
1 qt milk carton: 9"x3"x3"
soap refill: 9.5"x5"x4.25"
mane cleaner: 9"x3.75"x2.125"

The lunchbox dimensions dictate a 9.5"x8.5" area. A standard tupperware could be cut up & resized. A metal cage would work better because there wouldn't be any drag, but would be heavier.


cutting a 4.25" segment out of both & joining to make 4"x10"x8.5"
Laundry detergent & mouthwash would have to be in the smallest size. It would finally achieve its original goal of moving DSLR gear, water, extra batteries for very long runs.
Posted by Jack Crossfire | Dec 23, 2015 @ 06:48 PM | 3,450 Views
The vehicle undergoes extensive testing before its 1 way trip to the city. The heatshrunk pinion gear continued to hold up for 12 miles with the full gopro, 4Ah 7.4V battery, & headlights on. Used the 16 tooth pinion, going 9-10min/mile on flat ground. It won't go out until installing a properly fitting 14 tooth pinion.

Current use with the least efficient configuration has been 220-240mAh/mile. A 4.3 mile drive used 1Ah. A 7.75 mile drive used 1747mAh. The 7.75 mile drive had 1.4 miles at 17min/mile.

Suspension still seems to work with this payload. When rolling, the wheels can move in & out, finding an equilibrium. On the bench, various wheels move all the way out & stay there, making it tilt.