Jack Crossfire's blog View Details
Archive for November, 2021
Posted by Jack Crossfire | Nov 27, 2021 @ 02:07 AM | 27,175 Views
The left motor went to valhalla while slinging the DSLR 10 miles. Thus another day went to rewinding a motor with 20 turns of 26 AWG. The PETG motor mounts are taking the heat nicely, letting motor after motor fry. The retaining ring was documented to show future lion it was properly reinstalled. Those retaining ring pliers have proven essential.

Some notes during the replacement were crash damage to the bottom panel. The 1.6mm tread tire still delaminated. The next step would be 250C printing, but delamination doesn't seem to have any impact unless it picks up a branch.
Posted by Jack Crossfire | Nov 25, 2021 @ 01:29 AM | 16,516 Views
So the power burn with the DSLR + rudolf + headlights was 410mAh/mile. Tried to get the red glow reflecting from a tree tunnel. It shows up more when seen from behind. The EOS RP seems to have less noise in HDR mode. It takes 3 pictures with varying shutter speeds & might average areas which are properly exposed in all 3 areas.
Posted by Jack Crossfire | Nov 20, 2021 @ 07:12 PM | 16,300 Views
The amerikan people are in such war against pork, let alone meat, it's a rare day that rudolf brings back any pork flavor. Lions now manely buy grocery bags for garbage bags instead of putting food in. At what point are there so many restrictions on foods & grocery bags that it's no longer worth staying?
Posted by Jack Crossfire | Nov 17, 2021 @ 06:46 PM | 9,536 Views
The phone didn't do any better against TPU than it did against ziplock bags. The case got a piece of leather on the bottom, since that's where it slams down. There's still a lot of adhesive gunk near the bottom & scratching near the top because that's where it moves. The next meaningful improvement would require a PLA case with felt tape. There's no need for it to be flexible. The bottom needs a larger space to tape down. The bottom inside needs foam. The sides & especially the top need felt tape.

Otherwise, the goat wasn't fooled by the reindeer costume.

Goat vs Rudolf (2 min 4 sec)

Posted by Jack Crossfire | Nov 14, 2021 @ 09:40 PM | 7,109 Views
Another speed run after recalibrating the encoders was back to its norminal speed.

# dist sec min/mile
1 202 43 5:43
2 202 43 5:40
3 212 43 5:39
4 209 45 5:40
5 209 46 5:51
6 203 51 6:37

Power went from 324mAh/mile to 220mAh/mile. So the encoder system continues to be balky & drift for no reason. The motors don't stall when it starts drifting. They just get less efficient. It must be a bee's dick of alignment change making the difference.

Then, the lion kingdom set to the task of designing a new phone holder for today's gigantic phones. The ziplock bags of the last 5 years have been very abrasive & short lasting. They also haven't dried out. TPU is seen as more forgiving on the plastic, but bonding a TPU clamshell has proven the biggest challenge. There was an attempt to tack weld it with the heat gun while simultaneously gluing it. It was impossible to keep the heat gun from melting the wrong areas. The result was a really ugly & weak seam.

The leading plans for the clamshell are sewing it & metal rods. The problem with metal rods is the corners not having any bond. It might be good enough for the corners to flop around. The problem with sewing is getting it tight enough & longevity.

Another idea is to abandon TPU & line a PLA phone holder with felt. It would be very bulky on top of already ridiculously large modern phones.
Posted by Jack Crossfire | Nov 13, 2021 @ 02:59 AM | 7,830 Views
Another speed run with no headlights & no payload besides a shirt was the same as the full headlights.

# dist sec min/mile
1 202 48 6:15
2 200 49 6:29
3 311 73 6:31
4 305 76 6:38
5 310 75 6:41
6 409 103 6:44
7 411 100 6:41
8 406 104 6:50

The speed governor may actually have been set to 6 min/mile for the 400m. 300m & below were definitely set to 6 min/mile.

So definitely an aversion to a slight headwind. It's moved up plans to upgrade to 16.8V. That involves new motor drivers with bigger caps, a new mane board with support for thermisters, new motor mounts with spots for thermisters. The wiring will have to be more organized.
Posted by Jack Crossfire | Nov 08, 2021 @ 06:56 PM | 6,814 Views
Widened the tread to 1.6mm, increased the temperature to 230C, & baked the filament for 10 minutes. It still had voids, but some of these voids might be from horizontal expansion of underlying layers. Another thing which might improve layer adhesion is breaking up the smooth tread with slight angles. A smooth tread still has the best traction with TPU.

As bad as these tires are, they're under $2 & they still last much longer than lunchbox tires. Lunchbox tires were out of stock after 2019, due to that pesky transient supply chain disruption.

The old tire was destroyed. The lion kingdom's last bottle of rubber cement was done. Clear school glue has proven more effective. Haven't seen rubber cement locally since 2018 when it was 1st used to bond tires to wheels. It might have been banned for its unholy non vegan fumes.
Posted by Jack Crossfire | Nov 06, 2021 @ 02:56 AM | 21,327 Views
Without cyclops light:
# dist sec min/mile
1 204 46 5:57
2 212 46 6:6
3 203 46 6:1
4 209 45 6:1
5 211 47 6:14

With cyclops light:
# dist sec min/mile
1 207 50 6:25
2 205 49 6:19
3 207 49 6:19
4 203 49 6:23
5 210 48 6:23
6 209 49 6:31

It burns 130mA on a full 12.6V, rising to 146mA at 11.2V. It gets drastically dimmer below 11.1V. The $1 buck converter has a 3V dropout.

For 150mA to make such a difference in all out speed, it might be saturating the wires. Hauling a spare battery for the light wouldn't make it so slow. The original headlights are also obviously slowing it down.

The string came loose. Hitting it with the glue stick might keep it on. The good news is it made it possible to see the cracks in the pavement by virtue of its wide angle more than its brightness.