Skip to main content

K4221C Photo Cell Adjustment

I just replaced a K4221 Photocell with a new one.

The old photo cell failed in the "on" position, which is actually a great failure mode - I use the photocell to control indoor and outdoor lighting, and for safety reasons its important that it works.  So the lights being stuck "on" is a decent failure mode.

But the photocell was stuck on for, um, many years.  I didn't really notice that there was a photocell, and was just accepting that the lights were on 24x365.

Now with the photocell, my lights will be on roughly 16 hours a day. That saves a third off of my lighting bill.  In the scheme of things it will only save me a couple hundred bucks, but hey, rather I get it than OPEC.

My photocell has a tough job.  It is to turn on necessary indoor and outdoor lighting when it starts to get dark outside.  But the challenge is that the photocell is positioned so it receives a lot of artificial light from the urban street, and it is unreasonably complex for me to move it.

My goal is to get it to trigger the lights acceptably, and that means have it be "on" when it needs to be "on".

In the worst case, I can just disable it.  I can just leave the lights on 24x365 and be done with it.  And that might be the solution I go with.  But for now, I'll fiddle with it.

I oriented the sensor so it faces away from direct lights, in hope that will help.  I also used the metal shutter and some handy electrical tape in order to shield the sensor as much as possible.

The fortunate part of it all is that I can adjust the sensor from the ground.  There is no need for me to climb ladders or other nonsense.

I figure it will take a few weeks to get it just right.

Popular posts from this blog

Fixing a SodaStream Jet, part 1: Disassembly Guide

I've had my SodaStream Jet for years, and once in a while something has gone wrong. Disassembly is the first step to repair.  Start with this article to see how to disassemble the SodaStream, and then once you have that down, scroll through my other articles to see how I repaired specfic SodaStream problems. SodaStream Jet Disassembly Guide Tools Required Flat head screwdriver Phillips head screwdriver 1. Remove the Carbonator.  Duh. 2. Remove the black panel lever The front big black tilt lever needs to be removed first. Removing this panel is tricky, but it isn't impossible. Looking up at the bottom of the black panel, there are two tabs, one on the left and one on the right. These tabs fully secure the panel in place. The trick is to use a flat-head screwdriver under the plastic to gently lever the tabs out of the way.  Note in the pictures how I approach these tabs with my screwdriver.  I usually release the left side first, and then I release ...
Read more

Fixing a SodaStream Jet, Repair #2 - Broken Fill Button

My Soda Stream Jet's fill button broke, which means I can not longer carbonate water by pressing the pushbutton. This caused all sorts of grief in my household. Here is how I managed to repair my Jet to give it another 10 years of life (hopefully). First, a look at the button The fill button on the top of the SodaStream is actually a simple lever. Pressing down on the button moves a pin that does the actual work of pressing open the Carbonator's valve. Unfortunately, the axis point is fairly thin and can see a lot of stress. That's where my Soda Stream button cracked. [ I think the usage tip here is "don't over-press the button like a gorilla, it doesn't do anything but put high stress on the button."] Cracked levering point of the button The Pesky Lever Retaining Pin The Fix It was pretty easy for me to replace the button: Take off the back of the Soda Stream and remove the carbonator. Push out the the button lever's steel retaining pin. This takes qu...
Read more

Macintosh: Upgrading an eMac

It's been a long time since I wrote this article, but the fact remains: The good old eMac can still be useful if you take the simple steps to keep it as good as it can be.  All can run Tiger, and most can run Leopard - great operating systems for their day with a bit of useful life.  This article describes the procedure I used to upgrade my old eMac, including: Replacing the internal hard disk with a large capacity drive. Increasing the memory for performance Upgrading the operating system Here I'm upgrading a 700 MHz eMac, but the procedure and tasks for upgrading other eMac models should be almost identical. Upgrading versus Replacing My sister's eMac is of the 700 mhz variety, with 256 MB of memory. The machine seemed to be getting "slower", and the original 40 GB disk was becoming jammed packed with photos and iTunes, and within a few months she'd be out of disk space. There were two options to address the problems: upgrade the eMac, or go o...
Read more

Using a Garmin eTrex with a Macintosh or Linux

The Garmin eTrex series consists of decent, full featured handheld GPS units. The cheaper monochrome eTrex models have a basic RS-232 serial interface, and the color eTrex models sport USB connectivity. In this article I'll talk about my experience with connecting both USB and serial port versions of the eTrex series to my Mac and to my Linux-based PC. I personally use the Garmin Vista HCx GPS now, but the other Garmins in the eTrex series, including the inexpensive but well specified Garmin eTrex Venture should work the same way. Dealing with the eTrex Series with USB Most of the eTrex units with a color screen have a USB port on the back. Happily, this USB port uses a common USB connector, so it is easy to physically connect a USB eTrex to a Mac or a PC running Linux. The USB Port on an eTrex I have found two pieces of software perfect for use with a USB eTrex, without the need for special drivers: GPSBabel+ and Google Earth . The Mac version of the freeware program ...
Read more

Installing a CarPlay radio in a Honda CRV

I ended up buying a 2013 Honda CRV and decided to replace the stock radio/CD player with an upgraded unit.  This was far easier and cheaper than I imagined, but the hardest part was selecting a unit to buy  This article covers how I made my choice.   The basic form factor for my CRV head unit Selecting a Unit The Car I have a 2013 CR/V, which is the same series of all of the CR/Vs from model year 2012 through 2016. Therefore it was important to find a radio unit that fits this model. The CRV has steering wheel radio controls, and I wanted to use them.  This uses a technology called CAN-Bus, which is kind of like USB for cars.  Therefore, a CAN-Bus capability would be able to leverage all these steering wheel features.  In addition, the CRV has a backup camera that would be nice to tie into. And of course I wanted to leverage the existing speakers and USB port. Form Factor I wanted a unit that had a big display, and I wanted a unit that was easy to purchas...
Read more

Old Apple gear that keeps on ticking

I've been dealing with Apple computer gear for a long time, as have my friends and family. Here is a list of the old gear that me and/or my friends have in active service.   Note that this gear is in real service, and isn't treated as museum pieces or as part of a retro-computing hobby. 2008: Apple Airport Express, draft-N, first generation 2009: Apple MacBook, late 2009 (utility use only) 2010: Apple iPod nano, 6th generation 2013: Apple Airport Extreme AC 2015: Apple TV HD (4th generation) The big winner here is the Airport Express, which is modern enough to do its job, and it just keeps on going.  The device that my friend runs has been in operation for more than 125000 hours.  It received its most recent firmware update on 28 August 2018, 10+ years after its initial release. In terms of security: it has no open, unpatched CVE vulnerability reports.  Many generations of other routers have come and go while this one keeps going.
Read more

Other Posts

Show more