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Device, Software & Book Reviews

Technical, Hardware, Electronics & Surplus suppliers with fast shipping times to Florida

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Here is a list of suppliers located close to or in Florida, for fast shipping times:

  • Industrial Safety Products – Miami FL – Personal Protective Equipment.
  • MPJA.com – West Palm Beach FL – Surplus & Closeout electronics, motors, chemicals & tools.
  • Raka.com – Epoxy Resins, Fiberglass and other composite supplies.
  • McMaster Carr – fast shipping to just about anywhere, but PHEW those prices….
  • MonsterBolts – (I haven’t tried them yet, but the next time I need some fasteners I’m going to check to see if they are cheaper than McMaster…..)

Other useful suppliers located farther away:

EGO 7.5AH Battery degradation over time (3 year mark)

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I log how much power it takes to charge my Ego batteries after I use them. I’m using this as a stand-in for how much capacity they retain over time. You should know that I have a large lawn (in Florida) and cycle these batteries at least once a week (more in the summer) so these batteries are getting more of a workout than if you had a small city lot that you could mow a few times before charging the battery.

I have two 7.5 AH batteries (one bought before the other). They took 410 watt hours to recharge when new.   My older battery has three years of use, and has 63% of it’s original capacity (260 w/h).     The drop from year 2 to year 3 was from 75->63% [The batteries have a 3 year warranty, so the first battery is now out of warranty.]

My second battery appears to be following the same general trajectory, although it’s capacity is just slightly less than the first battery (at the same years in service mark).

For the bar chart above I averaged the capacity of all measurements in a particular year, but if you graph all measurements you can see that they are generally decreasing over time (although the batteries do sometimes go “up” in capacity, possibly due to ambient temperatures).   The following graph is for my 2nd 7.5AH battery (manufacture date of 2018).

High Accuracy GPS with RTK in Orlando

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Global Navigation Satellite Systems (GNSS)   receivers have made incredible improvements over the last twenty years. I remember having to stand outside for 10 minutes waiting for a US only Global Positioning System (GPS) receiver to lock onto 4 satellites so that I could get a fix with less than 100m accuracy (due to selective availability).   Now, you can buy a $220 GNSS receiver that can track 60 satellite channels simultaneously, start from cold in 25 seconds, lock into signals from satellites launched by four different countries (the USA, Russia, European Union, and China) and gets 2.5 to 5 meter accuracy all on it’s own without correction signals.

Here is a plot of the calculated location for a stationary antenna over time without correction signals (3D fix mode):

GPS location wondering around a 1m accuracy circle
As you can see, all of the readings are within a 1 meter circle of accuracy, which is quite good for finding your location on earth, but not (quite) accurate enough to drive a robotic lawnmower around and miss the petunias. [And from day to day you may be off by a few more meters…]
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How Harley Quinn: Birds of Prey could have been so much better.

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My wife and I went to see Harley Quinn: Birds of Prey for Valentines day. And yes, it was at least 50% her idea. The movie wasn’t bad, and had several good moments, but it could have been so much better.

My wife appreciated “the girls” kicking a lot of male ass, but several of the fight scenes went on for too long with too much gratuitous gruesome violence. (Maybe not as bad as the Myth Busters diving suit episode, but did Harley Quinn really need to break a bad guy’s leg in three different places with three different hits?) The bad guys were sick and gruesome as well, which served as their only character development and justification for getting their asses kicked.

The best parts of the movie—where they didn’t take themselves too seriously and embraced the camp without actually putting “Bam” and “Pow!” on-screen — almost rose to the level of Tim Burton’s Batman. Quirks like the ode to the breakfast sandwich,   stealing a mini-van as a getaway vehicle, Huntress being socially awkward, or one-liners such as “Hair-band?” shone like lighthouses in the fog, indicating where the movie could have gotten things so much better. Some of the action shots were amazing: Glitter Bomb bean-bag riot gun attack on the police station, baseball bat floor bounce, the fun-house fight scene, and the roller skate car chase. But many of them wore out their welcome and went on too long and over the top with violence.

I understand that the source material is dark, gritty and violent, but really, who has actually read those comics? Forget the canon, and pander to the crowds. Make it fun and campy, go for a PG-13 rating, and develop the other characters a bit more. Margot Robbie does a great job with Harley Quinn, but the other actresses didn’t have enough to work with.   As my wife said, “It’s no Wonder Woman”.

Project Source 11″ LED Integrated Light Failure (Flashing) IPX8011LS-ORB

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Two and a half years ago I purchased a 2 pack of LED integrated lights for my house from Lowes. They were the IPX8011LS-ORB units, and cost $50 for the two pack. Recently, the electronics in one failed such that the light would flash on and off quickly (2-4 times a second) instead of saying lit continuously once the electronics puck heated up. Here are some photos of the old/bad unit (click to enlarge).

Some of the model numbers I found in the old unit: C041218 (18W LED Driver Triac dimming)   BG0358-110C036-03 (on the circuit board) HH-03 94V0 E327405 4515 (also on the circuit board.

Luckily, it came with a 3 year warranty and I was able to find my receipt, so I took it to Lowes and they replaced it with one that looked exactly the same on the outside, but had a different item number on the box and a completely different set of electronics on the inside. Photos of the new unit, which has worked fine so far:

Serial/Model numbers/markings I found on the new unit: 41056, F11-1L   L.MAC6-1430-L021-00, KF-FAND-S008-V00 2019.01.07 1400LM (1400 Lumen?), Intertek 4008733,

DONGGUAN KEE TAT LIGHTING LTD.

 

UPDATE: March 2022, the 2nd (original) unit from the (original) 2 pack failed in the same way (out of warranty). I replaced it with an inexpensive fixture that takes replaceable (LED) bulbs.   [The replacement unit from the 2019 failure is still working fine…]

Ego 21″ mower (LM2100SP) 3rd self propel motor failure & repair report

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My Ego 21″ self propelled electric lawnmower started on its third self propel unit failure back in June of 2019.   For those keeping track, I bought the Ego 21″ mower back in April 2017, and it’s self propel unit failed in October of 2017 I took it to Home Depot to be repaired (which took 6 weeks) and the repaired self propel unit lasted until July of 2018. Ego customer support was nice enough to send out a replacement mower that time, so my downtime was only 10-15 days, and I was hopeful that the replacement mower might have a better self propel unit in it. Unfortunately, that one started to fail in June of 2019, so it looks like the lifespan of my self propel units are 4 months, 10 months and 11-16 months.

So, back in June 2019, the self propel unit just stopped working much like it had previously. I called Ego customer support and they offered to ship me a replacement mower. We had that all set up, but the next day I went out to push-mow the rest of my lawn, and lo-and-behold, the self propel unit had “reset” and was working again! So I called Ego back and canceled the replacement.     Unfortunately, although the self propel unit had not totally failed, it had not fully recovered, and still had some issues that got gradually worse over time. Specifically, the top speed was reduced, and over the next several months, the power and top speed appeared to keep dropping. Eventually it got to a point where it would not propel the mower up a slight hill without me assisting. Eventually, in January of 2020, the self propel unit failed completely, and did not “reset” itself.

Ego shipped me a replacement mower and I shipped the bad mower (my 2nd) to them, so I am now on my 3rd Ego mower (and year 3 of my 5 year warranty). However, for the first time in 3 self-propel failures the SP unit is different! The new mower (manufacture date October 2019) has a different style of self propel unit when compared to the three units that had failed on it in the past. The old unit had a gearbox on the drive shaft and the motor body stuck upwards at a 90 degree angle. The new unit has the motor body above but parallel (horizontal) to the drive shaft. I don’t know if the old unit had a fan, but the new unit has a fan clearly visible.

Older Self Propel Unit

 

New Self Propel Unit

Objectively, the new self propel drive unit doesn’t look as impressive as the older unit, but given the number of failures I have had with the old style, I’m excited to have something change (and hopefully improve). From a performance standpoint, the new self propel unit works just as well as the old style, so there is no loss in performance. I just hope that it will have more longevity than the older units.

I suspect that the size of my yard (which is large enough that it takes me two 7.5 AH batteries to mow it in the fall/winter, and up to four 7.5 AH battery charges in the heat of summer) may be the reason the self propel unit’s are failing. I suspect I’m putting a lot more “miles” on the SP unit than most Ego owners, plus they seem to be failing in the heat of the summer. I’m not sure if that is due to heat related problems, or if it’s due to the grass growing more in the summer.

Ego Battery degradation over time (2 year mark)

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I’ve been tracking how much power it takes to charge my Ego batteries since I purchased them. I’m using this as a stand in for how much capacity they retain over time. You should know that I have a large lawn (in Florida) and cycle these batteries at least once a week (more in the summer) so these batteries are getting more of a workout than if you had a small city lot that you could mow a few times before charging the battery.

I have two 7.5 AH batteries (one bought before the other). They took 410 watt hours to recharge when new. After one year of usage, the remaining capacity was (78% 320 w/h and 82% 340 w/h) on the two batteries. My older battery has two years of use, and has 70% of it’s original capacity (290 w/h).   So it looks like they drop between 18 and 22% of their capacity the first year, and an additional 8% the 2nd year for a total loss of 30% of their capacity after the 2nd year of usage. [The batteries have a 3 year warranty.]

30% capacity loss in 2 years

Update: See my new post at the 3 year mark for the 2014 battery (and 2 year mark for the 2018 battery).

Alpicool C15 12 volt car fridge / freezer review

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I bought an Alpicool C15 model compressor/refrigerant based car refrigerator/freezer for a project. They also have a C20 model which is exactly the same but has a “bump up” in the lid for 20 liters of capacity. I paid $145 with a coupon, and I’ve seen them retail around $190. Here is my Amazon Affiliate   link: https://amzn.to/2rwJvD2

Quick summary of the review video above:   15L interior capacity, can get the interior down to at least -12C, chills four 12oz cans to 3.5C in 4.5 hours, freezes 2 lbs of water in 12 hours, draws up to 50 watts continuous when the compressor is running (never goes above 150 watts on startup so can be ran by my Ego Nexus Escape). It averages 13 watts draw over a 24 hour period at 0 deg C without opening the lid (310 watt/hrs in a day). When set to -20 deg C it draws an average of 25.4 watts per hour (610 watt/hrs in a day).

The amount of insulation is relatively minimal (especially if you are using it as a freezer) but the internal volume / total surface area is small enough that it really doesn’t take up that much power as a refrigerator. Its all plastic construction and friction fit lid is cheap (reflecting the price I paid) but serviceable.   My unit was damaged in shipping and had some plastic break off the side, but still functioned fine. As I plan on voiding the warranty and most of the exterior case in my project, I didn’t mind, but a normal customer would have shipped it back to Amazon for a replacement.

Video on how to use the control panel (including converting the display to Fahrenheit) is here:

Ego Nexus Escape – What I wish I knew before buying

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I bought the Ego Nexus escape because Ego gave me a $25 off coupon and I have a lot of Ego batteries from my yard equiptment. I wouldn’t pay full price for it.

 

The Nexus escape is a   small 150 watt (max) SQUARE WAVE inverter that plugs into the top of Ego Arc Lithium batteries, that also provides 2 USB charging ports. Ego Nexus Escape (PAD1500) Amazon (Affiliate) link: https://amzn.to/2Z6qKBn

Great for charging USB devices, or powering small loads where the square wave power isn’t an issue (motors on fans buzz, but most power supplies such as for laptops, routers, etc work fine). The 150 watt inverter will shut down if the load ever goes above 150 watts, as it has zero surge capability over the listed 150 watts.

It will also go into a “low power shutdown” mode to save power if the draw is less than 4 watts, so it is not suitable for running very small loads unattended.

As a small 150 watt inverter, it is serviceable for most small loads, but I really wish it had either a modified sine wave or true sine wave output to make it compatible with more AC devices. Also, having a 300 watt surge capacity for a second or two would have made it much more usable.

Overall, I think the Ego Nexus Power Station is a much better (if much more expensive) product as it has a true sine wave power output, and a lot more capacity.

BEME ERod motor drive unit failures

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I have purchased three BEME Erod motorized drape systems (one in a previous house, and two in the current house). They have an infrared (IR) remote control that allows you to open and close the blinds at a push of the button, which is very useful if you have things in front of the blinds that make it hard to access the window, or if you just want to be able to open or close your blinds without getting out of bed.

Two of these units have worked flawlessly for several years. My third unit however has had two separate failures which I suspect may be due to poor quality parts.

The first issue crept up slowly, starting out as an intermittent delay in closing. The blind motor would make a “click” when you pressed the close button, but the motor would not engage for 20-60 seconds. Over time, the delay got longer and longer until eventually the blind refused to close. (Although the relay inside would still click when the button on the remote was pressed.)

Diagnosing this as a relay contact failure just from the sounds it made, I opened up the unit, found the part number on the relays, ordered replacements and (for good measure) replaced both relays. (I bought 5 of the relays, so I’m all stocked up for future relay failures.)
two blue relays on a circuit board.

When I had the unit open, I noticed that there was one extra red “re-work” wire on the circuit board, indicating that the PCB had a problem (either a trace left out of the design, or not correctly connected on the PCB during manufacture.) and had to be repaired at the time of manufacture. This is actually more common than you might expect on inexpensive consumer goods, and since the motor was working well with the new relays, I closed things back up.

Around six months later, one night with no prior warning, the motor failed to respond to the remote control completely. No clicking, so the problem probably wasn’t the relays.

Here was my diagnosis procedure:

  • I tried the remote on my other erod (despite the fact that the red light was lighting up when I pushed the buttons) to make sure the remote was working.
  • Because the motor unit was acting as if it was not receiving any power (completely dead), I took the power adapter and tested to make sure it was providing power by using it on my other (working) erod.
  • Now that I had determined that the problem was definitely with the motor unit, and not with the power supply or remote, I disassembled the motor unit.
  • I checked the fuse on the circuit board, as it is the first possible reason power might not get into the circuit, but it was fine. (Also, a small yellow LED on the circuit board was dimly illuminated when plugged in.)
  • I visually checked the capacitors to make sure that none of them were leaking.
  • Since I had a diode tester mode on my multimeter, I checked all the diodes (but didn’t really expect them to have failed….)
  • At this point, I noticed something funky on the circuit board. A small black component had one of it’s legs replaced by a resistor.   (You’ll probably have to zoom into the photo to see it.) Normally, if a resistor is called for in a circuit, it will have its own location on the circuit board. This resistor was definitely added in later in the manufacturing process, and was not part of the original circuit board design.   Since I hadn’t found anything else that would explain the failure, I felt that investigating this part was a good idea.

78L05 power regulator with a resistor replacing it's input leg

  • The part is a 78L05 linear power regulator, which steps the 12v input down to   5 volts suitable for powering the microchips that watch for the IR remote control signal and trigger the relays (via transistors).   The small yellow led was illuminating on the board when power was applied, so the 5 volt power rail should be working….but, the whole resistor leg looked dodgy to me. When I measured the voltage coming out of the 78L05 regulator, it was only 2.7 volts!   (Just enough to illuminate the LED dimly, but not enough to run the other ICs.) After looking up the spec sheet to make sure that it wasn’t a 3.3 volt regulator, and really was supposed to be outputting 5 volts, I knew that either the power regulator was faulty, or something farther into the circuit was drawing so much power that it was not able to provide the proper voltage.
  • I de-soldered the output leg of the power regulator from the rest of the circuit, and the output voltage went up to 5 volts, which hinted that the problem might be farther into the circuit. However, when I tested how much power the regulator could provide, it would only drive 17mA into a short! (A good regulator should provide 100 or 150 mA of power.)

  • I wasn’t sure if the resistor on the input leg was limiting the current that much, so I took the whole thing out and tried powering the regulator directly by bypassing the resistor, and it had the same low output current issue.
  • So, time for a new 78L05 power regulator. This is a VERY common 5 volt regulator, and I happened to have one in-stock, which I soldered back into the circuit. I considered leaving in the input resistor (520 ohm), but decided against it, as the original circuit schematic obviously didn’t have that part, and according to the spec sheet, a 78L05 should be able to go from 12v down to 5v without problems. I measured the idle current draw of the entire motor unit afterwards, and it was only 8 mA, so the voltage regulator is dissipating 12-5 = 7 volts at 8mA, or 0.056 watts (5.6 mWatt) continuously, which is trivial even without a heatsink.

My suspicion is that the factory substituted an “off-brand” (or even counterfeit) 78L05 power regulator which they knew would have trouble dropping 7 volts, so they put a resistor in front of it to drop some of the voltage/power external to the power regulator, but the cheap part still failed.   I’m hopeful that I have now replaced all of the parts that are likely to fail in this unit, and perhaps it will work well for me in the future.