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Raspberry Pi project – a milestone

After updating the humidity correction factors and clearing the log, I’ve now got a month’s worth of temperature and humidity data in the logs.

You can see that the upstairs temperature was much higher at the beginning of the period.  (click on the image to see the full size version)  That’s because I was there and was running electric heaters upstairs.  The temperature began to fall while I was getting ready to head home and turned them off – they are unplugged when I’m not there.  Seems smart to not risk an electrical problem and a fire when there’s no need for heating.

You can also see the daily temperature swings, more pronounced on some days than others.  The swings are larger when the sun is out, as you would expect.  The downstairs swings are not as big, because the windows have blinds (and there are only 2 windows downstairs vs 5 windows upstairs) so solar heating has less of a chance to warm things up downstairs.

The humidity is still higher than expected – I’ll need to recheck the sensors with the hygrometer and see if the numbers are still close.  Even if I wind up making a change to the humidity correction factors I don’t plan to restart logging.

Yes, it’s pretty cold inside right now.  That’s what happens when the only heat is a portable electric heater.

I’m sure you won’t be surprised by this, but I also made a couple of tweaks to the heat and cold alert functions in the python logger script.  When a heat or cold alert is rescinded, the email message includes the amount of time the alert was in effect.  Just a little more polish to the project.

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New sight time

The sight on my Bowtech Fuel compound bow is decent, and the fiber optic pins are pretty bright.  It isn’t a high end sight – it works fine, but is missing a few upgrades that a higher-end sight will have.  Where this sight falls down is in the adjustments.  You loosen a allen-head cap screw and move the scope right or left, up or down for windage and elevation, respectively.  The sight pins adjust in the same way.  There aren’t any markings to indicate how far you’ve actually moved it, so getting it sighted in is a bit of a guessing game.

I decided to see what other sights were available on the used market.  Good quality new sights are upwards of $200, so going used seemed the best choice.  I found a good deal on a Sword Maximus Pro sight on the archerytalk classified section, which has micro click adjustments for windage and elevation.  The price was fair so I picked it up.  When it got here, I was impressed with the construction quality – it’s just a solid and well thought out sight with a nice light for the fibers.  What was missing were instructions for adjusting the 3 axes.  Not really a surprise for a used sight – most folks don’t keep the instructions once a part is installed – some folks never read the instructions at all (Pot, this is the kettle.  You’re black.).

So I emailed the company and they don’t have a manual available.  Odd.  I would have thought a manual would be a common thing to include with any bow sight, but apparently not.  I was able to get some advice from folks that have the same sight, and once I had a point in the right direction the adjustments made sense.

The sight is mounted and leveled, next is to get it sighted in.  The sight is a 5 pin sight, but one pin is not installed.  so I’ll sight it in for 10-20-30-40 yards.  10 and 20 yards can be adjusted at the indoor range at the archery shop, 30 and 40 yards will need to be done outside.

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Restoring a classic Hoyt recurve

I decided to treat the Hoyt as a restoration project.  The history of this bow and the success archers had with it were the driving influence.

The limbs need nothing, but the riser needs some attention.  Since it’s a target bow, a brightly colored riser is the norm, and this originally came in black, white, blue, and red.  I think a metallic red would look great with the ivory colored limbs.  I reached out to Duane, a magician with paint who has painted and touched up several bikes for me.  I sent him a photo of the riser and told him what I had in mind.  He agreed to do the painting, and he already had some very nice red paint, a dark Mercedes red metallic.  Perfect.  I packed and shipped the riser to him.  It will probably take 3-4 weeks before I have it back and that’s fine.  I trust him to work his magic and I have no doubt of the quality of the result.

We’ve emailed back and forth about what can be painted and what needs to be masked off, so I think we’ve got that sorted out.  I have an arrow rest and a plunger ready to go on, and that’s enough to get started.  I’ll get the nocking points set up and then see how well I can shoot it.  I’m not expecting miracles here, I’m just learning.  Given that constraint, I’ll go slowly and make adjustments as needed.  Eventually I’ll (hopefully) be able to shoot it reasonably well.

Once I have the riser back from Duane, I’ll take some photos of it and of the assembled and strung bow.  Stay tuned.  If the shooting sessions go reasonably well, there might even be some photos of arrows in the target.  If they’re missing, well, then you’ll know how much work I have to do.

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Raspberry Pi project – tweaks

My temperature monitoring project has been running very well, especially since I corrected the humidity sensor readings by applying a correction factor.  And the upstairs temperatures did drop below freezing a couple of days ago, so the tasks of shutting off the pump, draining the plumbing, and adding antifreeze in the traps were absolutely worthwhile.

But I decided that it would be nice to know when some threshold temperatures were reached without checking the web page.  I added code to the python3 logger script to write a file when a cold or heat threshold was reached.  It also sends an alert email message when this happens.  The web page that displays the temperature and humidity graphs looks for this file and indicates that a threshold has been crossed for cold or hot temperatures.

It seems the DHT22 sensors can waver back and forth a few tenths of a degree, and if that happens right at one of your threshold values, you will get an annoying collection of emails.  To address this, I implemented a buffer mechanism.  Now, the heat/cold alert will only happen when the temperature crosses the threshold and stays there for 3 consecutive checks.  Since I’m logging the values every 5 minutes, that means the temperature must remain either above (heat) or below (cold) for at least 10 minutes before an alert is sent.  When the temperature rises above the cold threshold, it must remain above the threshold for 3 consecutive checks before the alert is rescinded.  Rescinding a heat threshold works the same way.

I also added some code to rescind any existing cold or heat alerts when the logging daemon is restarted.  Since you can edit the threshold temperatures, it seems reasonable to start clean.  If an alert should be issued, it will take just a few minutes to get past the buffer mechanism.

So far this is working well.  On my next trip up there, I’ll recheck the sensors using the hygrometer and see if any alterations to the correction factors are needed.  If they are, it’s a trivial change to make.

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Branching out

The compound bow kind-of equates to a modern bicycle in my mind, while recurve and longbows seem to be the bow version of classic bicycles.  If you’ve followed my bike builds, you know that I like classic steel bikes.  So it shouldn’t be a complete surprise that I would look for a recurve bow.

And I found one, a Hoyt Pro Medalist takedown bow, a TD/2 model.  This bow was made between 1976 and 1980 so it definitely qualifies as a classic.  In it’s day, this bow won literally everything there was to win in archery – from Olympic gold medals to World championships.  The asking price was reasonable, so I picked it up.

The grip was cracked, which is not unusual for these older bows.  The riser is cast magnesium and the grip slips onto the riser from the belly side of the bow (the side of the bow that is closest to your belly while shooting).  Finding a grip proved difficult (as in a complete lack of success) and then a post on archerytalk suggested that I look for a riser that had a grip on it that would fit the Hoyt.  I’ve been known to buy a complete bicycle to obtain some parts that are not available separately, so this seemed like a reasonable thing to do.  I found one and despite some shipping delays, it arrived in fine shape.  The grip is a tight fit on the Hoyt riser so I didn’t force it – I certainly don’t want to crack this grip knowing how difficult they are to find.

The rest and plunger that came with it were ok, but not great.  I figured out which rest and plunger would be good replacements and ordered them.

The limbs are 30# (30 pound pull) on a 24″ riser, so they’re a good weight to start with on a recurve journey.  They’re in excellent condition, no nicks or obvious wear.  Because this is an older bow, the recommended string material is Dacron.  The modern string materials are too harsh for these older limb without tip reinforcements so I ordered a new string made from Dacron.

Once the string arrived, I strung the bow and shot a few arrows into my target.  This is a completely different game to the compound bow.  Definitely a challenge to shoot well, but I like challenges.

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Video security system – a problem

I’ve installed the two indoor cameras, and unfortunately there’s a problem with the upstairs camera.  This is what the image looks like right before it goes completely black.  The IR emitters aren’t working.  So at night, the image is completely black.  Not terribly useful.

I used the reset link on the camera’s web page, but that’s a software reset, not a hardware reset.  I’m sorry to say that didn’t resolve the problem.

I contacted Amcrest, and explained my problem.  The response suggested that I would need to do a hardware reset, since the software reset didn’t help.  To do that you need to disassemble the camera so that you can access the motherboard, and press a switch on the motherboard.  That will reset the login password, IP address, and video stream configuration.  A nuisance for sure, but maybe it will resolve the problem.  Honestly, I have my doubts – and can I trust a camera that required a hardware reset to restore proper functionality?  When will the next hardware reset be required – a week or a month later?  I had him send me an email with the hardware reset instructions – disassembling the camera voids the warranty, so I wanted some way to demonstrate that I took it apart at their direction should there be a future problem with it.

I’m 5 hours away from the cabin, so I don’t just run up there to try every resolution immediately.  I’ll try the hardware reset on my next trip.  If it works, great – but as I said earlier – it will still be suspect.  If not, I have a plan B.

I’ll connect both uninstalled cameras to the POE switch with patch cables and make sure that they work properly and that the IR emitters are behaving.  I hope that both remaining cameras work properly and I’ll pick one and replace the upstairs camera with it.  I’ll need to reset the IP address, which is easy enough, and verify the video stream parameters as well.  Then I’ll have both indoor cameras working properly, and I can install the remaining good camera in it’s place on the roof soffit.  The bad one will be sent back for a replacement under warranty.  It’s not a difficult install, mounting the camera is pretty easy.  Running the cat6 cable is a little more involved but again not too bad.  Since I borrowed a cable tester from a friend (thanks Bob) I can make sure that the cable connectors are properly crimped on and that the cable is good.  Then I plug it into the POE switch and set it up in ZM.

I’ll leave this camera in Monitor mode for now, since it’s an outdoor camera I’ll need to set up detection zones and ignore zones to try and minimize false positives.  I don’t expect this will be a set-it-and-forget-it process, I think I’ll spend some time tweaking this before it’s reliable.

I’m curious what will show up when I change the mode to Modect and start recording events.

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Rekindling an old interest

I was over at my friend Greg’s house and he was shooting a new crossbow.  It’s a very nice one – fast, accurate and fun to shoot.  Greg is a very good shot with it. and I acquitted myself pretty well.  I’ve been wanting to learn to shoot a bow for a long time, and I’ve never actually taken a step towards learning.  Those few minutes shooting a crossbow at Greg’s brought back my interest in learning to shoot a bow.

I registered at archerytalk.com and started looking at used bows in the classified forum.  I found a couple that looked decent, and read some reviews to see if there were any problems with the bows.  I decided to make an offer on a Bowtech Fuel package that included a sight, rest, stabilizer, soft case, and some arrows with field points.  We agreed on a price and I sent a check.  He received the check, and a few days later shipped everything to me.  I got it and it was just as nice as he had described.

Being a complete noob at archery, I decided the smart thing to do was to get the bow checked out at a local shop and have it set up for me.  Greg and I went to Herndon Archery in Herndon, KY.  He looked it over and said the strings looked almost new, and the brace height was right at the spec.  He put it on the drawboard and said the cam timing was perfect, and the draw weight was between 38 and 39 pounds.  He gave me a release and an arrow and had me draw the bow.  He said the draw length needed to be lengthened to be a better fit for me.  On this bow the draw length can be set by moving a module.  He lengthened the draw length by an inch, and had me draw the bow again.  It felt better to me and he said it looked better to him as well.

He gave me some hints about foot position, bow hand position, and some suggestions about finding my own anchor position.  Now to see if I can actually hit the target with a bow.

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The first few shots

Greg has a target at his house, with a nice backstop behind it.  Not knowing what to expect with the first few shots, a backstop seemed like a pretty good thing to have.

I started at 10 yards.  The first few shots all hit the target.  Not too bad if I’m honest, and I was a little surprised.  Tried a few more shots at 10 yards and the group looked halfway decent.

I moved back to 20 yards and tried a few more shots.  These were a little low, but the left-right alignment was pretty good.  Wound up shooting about 20 shots at the 20 yard distance and the grouping was decent.

Moved back to 30 yards, and the group is definitely low.  Greg thought the bottom pin might be set for 25 yards, so I moved up 5 yards.  Now the arrows are grouping all around the center.  Not the best group, but not scar-me-for-life ugly.

It was fun.  I think it will take practice to become a good shot, but if I pay attention to the little details I can become a better shot.  I need to pick up some new arrows.  The wrist release I bought from Herndon Archery is working well for me, and the target is fine for practicing.

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Raspberry Pi project – some conclusions

After making the changes discussed earlier and monitoring the values and the graphs of those values, I can draw some conclusions about the interior conditions at the cabin.

First, conditions downstairs are more stable than the upstairs, both temperature and humidity do not fluctuate nearly as much as they do upstairs.  Makes sense as there are only two small windows downstairs, while the upstairs has five windows.

Second, it is cooler upstairs than downstairs – but a larger difference than I would have expected.  It is 4-5 degrees cooler upstairs, and more humid by 4-5 percent.  Some of the humidity difference is attributable to the temperature difference, but not all of it.  Solar heating during the day does warm the upstairs more than the downstairs – presuming that the sun can supply the solar energy.  On cloudy days, you’re on your own.

But my main interest was to see how close to freezing it gets inside, with no heat source to maintain a set temperature.  I can’t risk frozen pipes, so I drain the water system and put RV antifreeze in the traps and the toilets.  Maybe I’ve been wasting time and RV antifreeze when it isn’t really needed, but now I have a reasonably reliable way to monitor the situation.

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Raspberry Pi project – correction factors

As I mentioned earlier, I was suspect of the humidity values returned by the DHT22 sensors.  So I used a hygrometer to get a separate reading – not that the hygrometer is perfect, but my experience over the past couple of weeks was that it agreed with another hygrometer, the temperature and humidity were consistent, and believable for cool winter conditions.

I placed the hygrometer close to the sensors and gave it a couple of hours to settle in.  The temperature matched within a degree, so that’s great.  Not so great on the humidity side, I applied a correction factor of -16 to get the reported values in the ballpark.  Now the sensors are both reporting values that match the hygrometer within a percent.  A significant improvement.

To move one of the sensors upstairs, I took some cat6 cable and soldered the twisted pairs together to make a 4 conductor cable.  One conductor won’t be used with the DHT22 sensors, but I will need it for the BME280 sensors when I swap them.  I ran the cable upstairs, which took a lot longer than it took to type this sentence.  It’s a long story, don’t ask.  Connected everything up and booted the pi.

Upstairs temperature was fine, but the humidity value (again) was off the charts.  So I decided to try the +5v pin instead of the +3.3v pin on the pi for the upstairs sensor, as the connecting wire is now about 15 feet long.  The humidity value came back to reality and has stayed that way for a few days now.

I’ll leave the DHT22 sensors in place for now and see how they behave.  I am definitely going to swap the sensors, but there are higher priority tasks to do, especially since the current sensors seem to be behaving for now.