Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
I conjured a “test fixture” from a clamp, copper sheet, and copper tape snippets:
Baofeng battery – test setup
Which produced interesting results:
Baofeng BL-5 3800 mAh packs – Ah – 2019-05
The 250 mA load = 15 hour rate seemed reasonable to simulate radios spending most of their time in power-save mode, but the packs still delivered only 2.8 A·h.
The packs also claim an unnaturally precise 28.12 W·h, but they’re still underperformers at 20 W·h:
Baofeng BL-5 3800 mAh packs – 2019-05
Anyhow, I can run the radios for a week without (worrying about) running out of juice during a ride.
A reader asked how the M20 camera mount on my bike works with respect to the camera’s clock; this description explains a few things missing from the original writeup.
SJCAM M20 Mount – Tour Easy side view
Do you have to set the time & date at start of every ride?
The internal clock shuts down about ten seconds after you pull the battery. If-and-only-if you swap batteries fast enough, it’ll keep time forever. Screw up once and it snaps back to Epoch Zero.
“Car mode” automagically begins recording when USB power goes on, but the manual advises:
TIP: When using your camera as a dashcam, use a car charger cable and remove the internal battery to make sure it does not die out while you travel.
That’s because the M20 continues to run from its internal battery when USB power drops. After recording an hour of a parking lot or your garage wall, the battery dies and so does the clock.
Of course, without the internal battery, the clock dies ten seconds after you turn off the car.
The internal battery has many days of capacity with the camera turned off (whew!), so I conjured the case & PowerCore battery tray to handle our normal rides. The internal battery keeps the clock alive overnight and during the rain we’ve had for the last week, the PowerCore supplies juice during the ride, and I recharge the PowerCore every few weeks.
The M20 doesn’t draw charging current when I turn it on, but poking the PowerCore’s status button also turns on its outputs, whereupon the M20 decides it should begin charging and, bonus, draw power from the PowerCore during the entire ride. The M20 finishes charging while we ride, but the PowerCore continues supplying power and, when I turn the M20 off, the PowerCore sees no current draw and shuts itself off.
Only a geek could love a lashup like that, but it works around the M20’s broken clock and removes its battery maintenance hassle.
We’ll be tackling several long-delayed household projects during the next month. As a consequence, I won’t be doing my usual techie tinkering and will post shop notes only occasionally.
There’s not much to say about scraping, priming, and repainting, other than that it’s an ugly job which must get done!
Turkey on patio rail
If only we could train the turkeys to scrape the rail …
The config/hostname.conf file (found under /system/sdcard/when the camera is running) file defines the camera’s name:
Cam4
That file overrides the contents of the usual etc/hostname.conf file, somewhat to my surprise, which remains the default Ingenic-uc1_1.
The bin/hostname utility returns the hostname:
[root@Cam4 ~]# which hostname
/bin/hostname
[root@Cam4 ~]# hostname
Cam4
You can automagically get the hostname in the on-screen display by modifying the OSD formatting variable in config/osd.conf:
OSD="$(/bin/hostname) %Y-%m-%d %H:%M:%S"
Which works because the main OSD script sources the config file to set the variable:
Xiaomi Dafang – 15-04-2019_13.26.18
It’s also helpful (at least for my purposes) to add the hostname to the image filenames. A one-line tweak in the scripts/detectionOn.sh script does the trick:
The ESR02 reports one as a 4.8 µF capacitor, the other as a “defective part” with a 4 kΩ resistance. Having a cap fail by turning into a resistor is surprising; I’m more surprised it didn’t simply burn up.
