In lieu of 6 digital signals, the Si4463 should ideally be used in FIFO mode. That would get rid of the UART wire, leaving just MISO, MOSI, CLK, CS, & SDN. It would require a change to the receiver side & the receiver would have to constantly poll the FIFO. It's not clear how chip radios modulate the data in FIFO mode, for purposes of using a UART to receive a packet sent in FIFO mode. The UART pin would have to be scoped.

After a resurgence in dropouts, the frequency hopping went back to configuring the base frequency instead of using channel indexes. The 30Hz error might make a difference. Also, the decision was made to try making it chirp when going into low speed steering. It's definitely better than nothing. The mane problem is the center & deadband have to be hard coded. It would take 2 way communication with the full quality of service to get the settings directly from the phone to the controller. It might be easier just to make the programming header easier to access.

To make it chirp for steering, it went back to 32Mhz full time. That might also have improved reception. It now burns 25mA.

The weather finally dried up enough to run down to the phone tower & verify the Si4463 was still powerful enough at .1W to overcome the phone interference.

The original CC1101 based controllers burned some 50mA. They were used in full time transmit mode & put out 15mW. No speed buttons or sound effects. Only left paw support. Those...Continue Reading

Startup problems continued until yet another bodge wire went to the SDN pin. It just needs to be manually kept in shutdown until Vdd ramps up. It takes 5 digital signals to use the radio.

Attention turned to reducing power usage. It burned 50mA. It was found that running the PIC on 2Mhz took away 2.5mA, but take whatever you can get. The PLL runs at 32Mhz but not at 2Mhz, which made for some difficult programming. It could run at 32Mhz only when playing sounds & run at 2Mhz most of the time. To run at 2Mhz, the ADC had to be gated to keep it from contending with the frequency hopping interrupt.

It was found that the serial port burned 5mA, so that had to be disabled when not transmitting.

The mane power user ended up being the radio burning 20mA in standby mode. It was found that all the GPIOs had to be in TRISTATE or INPUT before it would go to 0.

Then to shorten the radio duty cycle, don't poll for CTS at all when going in & out of standby mode. Use the channel number instead of changing the base frequency for frequency hopping.

The sum of all those changes was a 21mA average burn. It should go at least 10 hours.

The transmit LED is invisible in daylight, so that could probably die.

Range is definitely lower with the .1W Si4463 than it was with the .25W RFX1010. Testing immunity to phone towers requires better weather. Timing glitches happen with the clockspeed switching. It would need a separate oscillator to be truly bulletproof.

What a lion would do to reduce the truck's standby power, currently 150mA. That's manely the STM32 & the bluetooth. Motor commutation takes a high clockspeed.

During the assembly, the best way to install the hall effect sensors was still to put a dab of hot snot down 1st, then press the hall effect sensor on, then flatten the dab. A dab of grease on the hall effect sensors still made a big improvement. Grease should not go anywhere else as it causes sticking.

A new trick with PLA welding was to melt the PLA with the iron but use the mark 1 lion paw to press it down. It adheres to the iron but not to the lion paw.

Power consumption was 50mA with the LED 46mA without it, so a 260mAh battery is only going to last 4 hours on a good day. It needs the 400mAh battery which somehow fit in the last one. The 260mAh required a lot of coaxing to fit in there. If the radio constantly transmits, it burns 120mA. The transmit duty cycle is 5ms on & 35ms off. The PIC has to run at full speed for the sounds.

There's 1 heroic bodge wire to connect MISO to the radio. Despite every effort, the radio failed to initialize without several power cycles. It didn't respond to a warm restart. It might require connecting the SDN pin to force a cold reset. It never failed in testing, which means the power ramp of the battery could be the problem. The datasheet says Vdd needs 1ms ramp time. The LP2989 has a 5ms ramp when probed.

Merely cleaning the flux got it to start despite the LP2989 issue. Getting rid of 100uF of capacitance didn't do anything.

After fighting to get the sock over the LEDs, it was decided to put the LEDs inside the case & hot snot the LED holes shut. With orange PLA, the charging LED shows nicely but the transmitting LED is barely visible. Transparent PLA would be ideal, but there's a real need for white PLA for an LED diffuser. Nylon paper might work as an LED diffuser, which would make transparent PLA the better deal.

A TPU test sock finally emerged. If there's any evidence of how bad lions are at 3D concepts, it took a long time to realize the finger grip could be part of the sock. It actually holds water & seems to have enough friction to stay on. The mane problem is the welds don't go as deep as hoped. No point in using orange PLA if the sock is covering it. Low cost TPU is quite good for covers like this. Trying to stretch it over the steering stick was hopeless, so it got a cutout.

Welded hall effect sensors were a failure. Those went back to hot snot, but with a soldering iron applicator.

Welded switches sort of worked. The switches still need to be lower. The welded inductor seems to work, but it needs more support on the underside to avoid flopping around.

2 days yielded some plastic rivets, but many hot snot requirements remaned. Sometimes, there's no easier solution than good old snot. There's a theory that the hall effect sensors can be retained by melting the adjacent PLA. The trick is the ridge which forms when melting PLA.

The 1st sock design emerged. The 1st design would try staying on with friction. It's going to take some experimentation to see how much water gets through. High humidity is making lions reluctant to print anything.

The amplified transmitter board worked flawlessly in 2 controllers since it was designed in 2021. Sadly, its 3rd copy was dead on arrival. The RFX1010 amplifier would not respond to its TXEN pin. It would randomly turn on permanently, depending on the board's orientation. The DET pin would rise to show it was permanently on & ignoring the TXEN pin. The truck would only receive packets when the RFX1010 was on. 2 chips behaved the same way. It was the kind of behavior that would only happen if TXEN was floating. If a power pin was floating, it would not turn on permanently. The TXEN pin was getting pulled down to 2.5V, whether or not the amplifier was working. Connecting TXEN directly to 3.3V drew 700mA & killed the chip.

It's the 2nd time an RF chip died, let alone 2. The last one was a CC1101 which seemed to be water damage.

The RFX1010 was being run at .2W to make the battery last longer. The latest sub Ghz radio transmits .1W without a front end. It's time to abandon the RFX1010 & redesign for the SI4463.


In the waterproofing department, the concept evolved to keeping the existing enclosure without the grip. A welded TPU sock would slide over the bottom half & have the grip. It would be held in place by either a notch or a widening of the enclosure. The TPU sock would come off for charging. The buttons have to be enclosed on the front side.

So the up button died, then the steering died & then the power switch stopped working. On the inside was tons of salt intrusion. The up button was water damaged. The other buttons were intact.

A wire in the charging circuit oxidized through & broke. That caused the battery to die, steering to die, & the power button to die. The hall effect sensors don't work below 3.3V. The battery fortunately had a protection circuit which disconnected it at 3V. It was believed to come from a bluetooth speaker long ago.

The up button was a bigger problem. The oxidized leads weren't broken. The only other fault could have been salt inside it. The only way to replace it is to build a new controller.

Disappointing that piles of salt formed despite all the taping. It's going to need frequent cleanings. The next teardown shouldn't be a cleaning but a full rebuild with a new circuit board.

Getting a year older, owing taxes, & finishing a year poorer than a year before sux, but to soften the pain made a collage of the inventions of 2022. There was a lot of crap created in 2022. There will be more crap in 2023 & lions will be better off materially if not monetarily. In the long term, being temporarily light is better than being only invested in meme currency.

Time for yet another left motor winding. This time, it was actually cogging differently during a motor test. There's normally no visual difference besides reduced torque. There was no odor of burning enamel. The leading plan now is to upgrade to higher temperature magnet wire. The wire of the last 3 years has been the lowest temperature rating of 155C. The failures have been progressive rather than sudden failure of the enamel or desoldering of the leads. Most magnet wire is 200C.

The major operation of installing temperature sensors is now envisioned to involve new motor mounts. They'll have cutouts for sensors. A piece of TPU will provide static pressure against the motor.

A permanent power lead for the leash was finally installed.

20 miles this year, at 335mAh/mile. Surprising how efficient that was. Burned 1 battery at a time with a battery change. This has proven superior to burning them in parallel. Burning them in parallel causes 1 to discharge a lot more than the other. The switch seems to resist a lot of current. A nominal load doesn't crush the tires as much as feared, though top speed is greatly reduced.

The last of the matterhackers PRO TPU yielded the last 2 tires of a new set. The entire history of that $50 roll only yielded 4 acceptable tires.

As expected, printing failed consistently above ambient 73F but worked consistently below 73F. Nozzle jams happened on layer 2 & layer 109 on 1 tire. Fortunately, rear tires can be printed in multiple parts & welded. This was how tire width was fine tuned. 3 designs went into the front tires & they're still too soft. They need to migrate to a bigger hub & honeycomb.

Noted that the outside tread was always smooth while the inside pieces were always sponge. The uninterrupted extrusion for the outside tread might have come out slightly cooler than the repeated retractions for the inside bits. The slight difference in heat might boil off more water. Maybe the amount of mixing caused by retraction boils off more water.

Retraction distance is the next leading suspect in the nozzle clogs. 7mm might be pulling the heat break in, but 5mm left tons of stringing. CHEP actually uses 2mm.

The sprite extruder was the big thing last year. That $90 tag apparently still yielded nozzle clogs despite having dual gears, direct drive & a better heat break. The big thing this year is water cooling the radiator. That adds a lot of weight to the X axis.

The rumors are peltier cooling requires a gigantic heat sink. Some combination of peltier & air cooling might be possible, where the hot exhaust dries the filament while the peltier cooler cools air that is blown on the stock radiator. Maybe there could be a 2nd XY table which moves the peltier system in unison with the printer. This would definitely not fit in a $1 million apartment.


The 1st 8 miles with the soft TPU tires were real quiet. Direct drive finally achieved the promise of silent driving. Traction was greatly improved, maybe even better than Vibram rubber. Helas, power increased to 326mAh/mile.

The steering plate finally shattered after hitting a routine curb. It seems the hard TPU tires & PLA wheel forks don't offer enough cushioning. The new plan is to convert all the tires to soft TPU & burn as much cash as it takes to improve the process.

The last of the matterhackers PRO TPU still jams 9 in 10 times. The latest theory is ambient temperature below 73F makes it go through. Ambient temperature above 73F makes it jam. Is it the hardness of the filament or the sharpness of the heat break? Between the bowden, EZR struder, & direct drive, the direct drive does best but when the nozzle clogs, no amount of force will push it through. Some failures can be attributed to friction in the bowden tube. The constrained path of the EZR struder offered no improvement. Obtaining a sharp heat break is the latest focus.

It always clogs during the 2nd layer of a tire print. Pulling the filament out & putting it back in recovers it. Originally thought it was back pressure from the 1st layer being on the bed. Upper layers have more cushioning. The 2nd layer isn't critical in a tire.

There's still a chance improving the heat break can increase the yield. The next step was more attempts to cover up just enough of the fan to block the heater while exposing as much of the heat sink as possible.

The filament went in the solar drier for 1 day since it had begun to hydrate. The next tire was a sponge. It seems the solar drier is too cold in our tule...Continue Reading

After 2 weeks, the last rear tires were already pulverized. The front tires similarly broke apart after 8 months. It seems the cold weather makes them harder & more brittle. The decision was made to finally burn the rest of the 2 year old Matterhackers PRO TPU on tire experiments. The roll had never previously printed without clogging.

After 2 years, it finally finished a successful part with 260C .8mm nozzle .32 layer height. That combination + lucky ambient conditions managed to keep it from clogging for the 1st time. 240C .8mm nozzle .32 layer height clogged. 260C + .4mm nozzle .32 layer height clogged.
It might be time to improve the nozzle cooling.


The new tire has .9mm replacing the .5mm lines. 1.5mm replaces the 1mm lines. This compensates for the filament being much softer but increases the weight to 115g from 65g. The truck with 2 softer tires is 100g or 3.5oz heavier. The new tire is still slightly more compliant than the harder filament tire. It might need 1mm replacing the .5mm lines to make it stiffer & a reduced diameter to make it lighter.

New front tires were printed with harder filament & are about as hard as PLA. 260C might be making the filament harder & more brittle. A test print at 230C was just as hard, so that leaves heating in the filament drier causing it to anneal or just crummy filament.

Matterhackers PRO TPU is discontinued, but it might have been rebranded ninjaflex. Hard TPU tends to be below $30/kg. Soft TPU tends to be above $50/kg. There's really nothing on temperature & price vs. hardness while shore hardness is considered meaningless. More successful prints have to be done before buying more ninjaflex.

It's all about how much you can reveal without revealing anything. No views other than the nose. Suspect the wings are swept back like a delta wing, hence why there's no other camera angle. The shadow is a delta wing, but it's an ultra wide angle lens.

Smart leash (2 min 26 sec)

The last tires were printed on 9/29/22. Within a week, they already had plants growing out of them. After 2 months, they were a case of Mars rovers. They were the shortest lived of any tires.

The next filament had 1 month in the solar filament drier. They came out as good as any TPU tire ever came out. The mane voids were next to the Z seams.

The increased wear may be because the latest tread is digging in more than any other tread, even though it's not obvious when driving. The treads might have to be solid & they might need another 5mm of cushioning. They could get a lot more expensive, but everything else is 50% more expensive than last year.

was still a failure with the direct extruder. It didn't jam like it did with the bowden + EZR struder, but it appeared to suffer from heat creep. It was far too soft, so would require much more material than Sunlu TPU if it extruded properly. 260C was printable with Sunlu TPU, but not pro TPU. It might be stuck at 230C.

The lion kingdom can't afford enough pro TPU to dial it in. It might be used for a key container.

The lion kingdom has evolved to using 2 batteries. 1 battery is the A battery for 10+ mile trips, once a week at most. Another battery is the beater battery for daily sub 10 mile trips. It's cycled every day & after a year is down to 3Ah from its original 5Ah. Eventually the A batteries become B batteries. If the routine evolves to 10+ miles being a daily event, the beater batteries get replaced more often in order to manetain the range.

xyz

3 months after the left motor winding died, the right motor winding died. This one died in the dead of winter no less & smelled like burned enamel. It was last rewound on April 29 so it only lasted 7 months. They're rated for 150C & they're confirmed to melt at 300C. Lower temperatures allow longer duty cycles, but all temperatures eventually melt.

Suspect running faster more often is burning them out. At this point in the history of motor rewinding, nothing new could be added. The question is when is rewinding motors going to take more time than designing a temperature sensor.

Left Motor windings:
Nov 27, 2021: 20 turns 26AWG
Sep 24, 2022: 20 turns 26AWG

Right Motor windings:
Apr 26, 2022: 20 turns 26AWG
Nov 22, 2022: 20 turns 26AWG