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• Odor 2, inlet restoration

  lion mclionhead • 02/07/2024 at 06:56 • 0 comments

  Sadly, the new blower with new filter had the same odor problems as the old one.  The filters seem to collect whatever odor is around, concentrate it & redistribute it instead of filtering it out.  It's normally ascorbic acid taken by lions but sometimes it's cooking.  

  https://www.amazon.com/gp/product/B0895737RT

  They were $10 per filter. 
  

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  After a long, cold spring, the inlet returned.  This time, whacked it right on the grille with no weather stripping.  It didn't rattle though it did introduce a wind noise.  Shifting it around seemed to reduce the wind noise.  Most of the air comes through the inlet this way while some of it comes through the sides.  It's not ideal to have most of the air getting sucked through a small part of the grille.  Lions deplore the idea of removing a hole from the grille since the grille seems to take out a small amount of dust before the filter. Eventually, it won't be covered by the inlet & become a regular desk fan with F-35 heritage.  The inlet could be spaced by some weather stripping, but the weather stripping of the last 20 years has become expensive & single use.

  The leading idea has been to fabricate a new inlet out of PLA, wooden dowels, & posterboard.  It would have a bigger opening than the laundry machine tube of the last 20 years.  The trick is making it modular for winter, aimable on 3 axes.  It almost has to be a separate F-35 nozzle with a much bigger diameter.  A rectangle inlet would need much less space.  2 laundry machine tubes have achieved a larger area in less space but not the largest area.  It may be just packing consumable weather stripping in a rectangle around the grille is the best way to improve the airflow.
  

• Blower replacement

  lion mclionhead • 02/04/2024 at 03:45 • 0 comments

  After 20 years, the original Hunter started squeaking more & more, regardless of lubrication.  After a failed attempt to build a custom blower, 1 of the last used hunters arrived, with enough spare parts to supply the rest of the lion kingdom's renting years.  The new motor didn't fit the old enclosure so the decision was made to replace it, altering the new enclosure as minimally as possible.  It would be a shame to completely destroy 1 of the last hunters.
  

  Repeated some of the modifications done 20 years ago.  Using lessons learned, JB welded the switch standoffs to get ahead of the cracking.  Modified the shape of the outlet to conform to the nozzle.  JB welded in nuts for the nozzle.  Added XT60 connectors to the wiring to make it possible to clean.  

  Using lessons learned, marked the orientations of the switches.

  Decided to give the stock filter assembly a try.  Young lion destroyed the previous one to stack 2 filters & make it easier to clean.  They were being made in the zillions, in those days.  It'll probably have to be ground flat & the painstaking packing tape used again.
  

  Scrapped the ionizer since it deposited soot everywhere, but it left behind a 7kV transformer.

  
  
  
  
  
  
  

  It's easy to imagine grinding holes in the front panel to reduce the cleaning, while still using it to support the inlet.

  The nozzle adapter leaked so much less on the new one, it didn't need any duct tape.  Sadly, it seems to move less air than the old one.  It might have been a compromise to use an ionizer or the nozzle adapter might not be as efficient.
  

  The old one will probably never be used again though lions imagine it being used in a bigger space. 
  

  Filter after 3 months.
  

• Odor

  lion mclionhead • 12/02/2023 at 23:05 • 0 comments

  The moldy odor which started in the 1st atmospheric river of 2022 continued to 2024 despite changing filters & drier weather.  Higher humidity enhanced it.  It became quite overwhelming & there are theories it could cause respiration problems.
  

  The leading theory is it started with vitamin C megadosing.  The ascorbic acid caused the sheets & the clothing to smell like musty paper.  That might be getting captured by the filter.
  

  The internet says ascorbic acid smells like hot dogs.  They might be thinking of formaldehyde, but few animals now online have any memory of formaldehyde since it was outlawed after generation X.
  

  Another theory is the brand of filter from 2022 contains some impurity.  It was always assumed the Hunter 30055's filters went out of production & the current ones were all old stock.
  

  There could be impurities in the blower itself, but this wouldn't fit the pattern of a fabric smell enhanced by high humidity. 
  

  1 solution is to spray the filter, but this would be temporary & clog it. 
  

• Blower rebuild

  lion mclionhead • 10/23/2023 at 01:06 • 0 comments

  The filter became ripe after another 11 months.  This year would be a full rebuild.

  The filter lets you know it's in need of replacement when the apartment smells like a moldy school library.  After the wettest year on record & a very humid summer, a large nest of spiders had grown in the opposite corner from the inlet.  Some spiders escaped to other areas of the apartment.

  A giant gnat invasion manifested on the other side of the filter.

  After 5 hours of insecticide & washing, the new filter was installed.  Helas, the moldy filter smell was replaced by the smell of insecticide.  The early 2000's design featured many round edges in keeping with the times, making it impossible to seal.
  

  New weather sealing was installed.  Weather sealing is not adhesive.  It has a mild adhesive for positioning it.  This roll burned $7.
  

  The speed control features no fiducials so whether high is low is completely random.  This early 2000's design was the epitome of non manufacturability & non user servicability.  There were no user serviceable parts.  The wires had no connectors.  Parts don't automatically align themselves.  Much soldering made it somewhat serviceable.  It was designed to be manufactured only once.  As bad as times are, we're still better off than 2000.
  

  Fully rebuilding it would take 3 days.  Cleaning the air inlets is another day.  Fully sealing the air passages is another day.

  The question remanes of how to build a custom blower.  The 30055 was originally 110CFM.  The easiest solution is to extract the blower from another Hunter 30055 & put it in a custom enclosure.  There are Hunter 30055's on the fleebay for twice the price of when they were new.  They're more yellowed than this one & probably brittle.

  The Ender 3 can print a 210mm diameter blower.  The bed is not square.  A concept print would take 11 hours & cost $5.
  

  A thought experiment is whether the original 30055 enclosure would have been better at sealing the filter than the tape hack.  It originally got destroyed to save money on filters before discovering it needed a filter to avoid destroying the motor.  The days of cleaning it after using it without a filter for a year were the days.
  

• Toroidal propellers

  lion mclionhead • 02/10/2023 at 22:09 • 0 comments

  Manly scott's transonic trussed based wing video triggered a wave of interest in toroidal propellers.

  The thing is, ring wings have been around the rcgroups & gizmodos for 20 years but the message didn't propagate at all until a Manly scott made a vijeo. 
  

  They're being emphasized just as quad copter propellers, probably because quad copters sell more ads than ventilation fans.  In reality, the extra weight of the joiners doesn't help quad copters.  The mane benefit is in making them quieter.  They could be a good way to make ventilation fans.  A wall of fans which would have been too noisy might be practical.

• Filter emergency

  lion mclionhead • 12/27/2022 at 21:23 • 0 comments

  The pineapple express arrived & the filter became ripe.  Thus began another 1 hour filter replacement.

  There is a desire to grind away these fiddly bits, but other problems are the curved areas.  There could be attachments for the curved areas to make them straight.

  Taping over all the fiddly bits to keep air from leaking takes forever.  Pipe fittings could be printed,for a lot of money.  

  The mane problem with building a custom blower to replace the 20 year old Hunter is the cost of a bare blower.  Large, silent, efficient blowers are expensive.  There's not much left of the original Hunter 30055.  A modern air purifier could be similarly stripped down.  Prices have quadrupled since 2003.

• Nozzle plan

  lion mclionhead • 10/16/2022 at 06:46 • 0 comments

  The unlocked nozzle angle has worked nicely, manely because there haven't been many needs to reset it.  The lion has managed to remember to manually fix the roll before resetting it.  The unlocked nozzle angle has also increased the encoder drift.  There is a plan for achieving higher precision & using quadrature encoders.

  It's going to have 2 fat power wires & a single data wire connected to all 3 motors.  All 3 motors get the same circuit board, which has an H bridge & brain.  The lowest board is stationary, controls all 3 motors, has an LED, IR receiver.  It polls the motors with serial commands.  All the motors have quadrature encoders.  Either the polling has to be real fast, the boards have to buffer encoder ticks, or the motors have to be real slow.  It's believed this arrangement will free up enough wire so it can handle a full 360 deg rotation during a reset if the lion forgets to manually fix the roll.  

  A simulated 300:1 gear ratio looked like an acceptable speed, but it may no longer be possible to turn it by paw.  It might need rotation without reset.  Besides the motors, it needs the H bridges & microcontrollers.  The reserve Atmega328's might do the job but are big.

• Unlimited nozzle angle

  lion mclionhead • 09/26/2022 at 17:59 • 0 comments

  According to the internet, cold air must be blown upwards to displace hot air.  The problem is the nozzle's limited range only allows it to blow down.   Another problem is the air inlet is on the bottom of the window.  The height of the effluxing hot air will have to be studied.

  Getting the nozzle to point up requires rotating the nozzle's inner ring more than 1 revolution.  It can't be tracked with a boundary sensor.  

  The leading idea is now a 2 step manual reset process.  1st, the outer 2 rings are reset automatically.  Then the user uses the remote control to align a fiducial on the inner ring.  The inner ring just has to get within a 180 deg range.   Then the program resets the inner ring as it did before.

  Another theory has an accelerometer on the middle ring giving extra information about the inner ring's position.  This would make the reset automatic.  This involves a lot more wiring.  When the motors switch to quadrature encoders, it might be lighter to put a control board & H bridge on every ring, in which case 1 accelerometer makes sense.

  Another theory says accelerometers can replace all the encoders.  The accelerometers could eliminate all reset procedures.

  Whether or not accelerometers are used, there's still a case where more than 1 revolution of the inner ring could lead to the same accelerometer position.   It would need either a deadband or a manual reset procedure.  The easiest next step is just a manual reset procedure.

  Quadrature encoding may still never happen.  Binary encoding with debouncing has been good enough.

  The current nozzle has 6 wires for each motor.  2 motor power, 2 sensor power, & 2 sensor outputs.  For quadrature encoding, it's finally practical to go with a multiplexing board for each motor with just 4 wires: 1 GND, 1 logic power, 1 motor power & 1 data.  That would multiplex 1 boundary & 2 rotation sensors.  A way to limit current in the motor could get it to 3 wires.

  As problematic as the nozzle is, never forget the 20 years of torture which the nozzle fixed.  

  The decision was made to eliminate all limits on the nozzle angle.  The user has to make sure the motors are all facing down before commanding a reset.  It's a half manual reset.  There's always been an abort functionality during reset.  Press the reset button during the reset procedure to stop the motors.
  

  The kinematic solver is brutal.  There are 2 sets of limits.  1 set of limits is for the lookup table which translates nozzle pitch to motor positions.  Another set of limits is for the raw encoder values & is tied to the 1st set of limits.  A 3rd set of limits would be required to limit the nozzle angle to a range beyond a single revolution.  The nozzle pitch should be independent of the nozzle angle, but it was written before the kinematics were fully solved.  
  

  The user has to make sure the cables don't run out of room.  Since most usage is loading a preset & tweeking 1 or 2 stops, it's not normally a problem.

• Power upgrade

  lion mclionhead • 08/17/2022 at 00:59 • 0 comments

  After 2 years, it started resetting when trying to move into certain positions.  Obviously, the motors were stalling more as they aged, causing brownouts.  The decision was made to whack on separate buck converters for the motors & brain with separate grounds.   The dream was originally to run it all on a 5.2 brick, but it was not to be.  A 12V brick was put in.  

• Video

  lion mclionhead • 06/14/2022 at 20:39 • 0 comments

  Finally got around to the movie.

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