The Raspberry Pi Thread [3]

caperjack said:

can I pick your brain for some info , on a acer switch battery pack ..I have a non working switch and I took it apart and have the battery out of it ,actually 2 batteries rapped in plastic ,it has 6 wires coming from it ,2 red 2 black and 1 white and 1 yellow ,it ratings say 3.8v typ:5901 mah/22wh , min:5700mah/21.5wh

I'm thinking the white and yellow are maybe for charging the batterys ?
I was thinking I could maybe take the plug off and connect 2-red to each other and 2 black , and put I small plug on them that will connect to the 1000 powerboost board .think it will work ..

I would say (best guess) is the two big square pads on each battery are the battery terminals. One will be + and the other -. Put a voltmeter across those and see what voltage you get If they are charged you should see around 3.7 or 3.8V. The two yellow wires are likely a temperature sensor to stop the batteries from overheating during recharging. The two large pads will likely trace back to the red and black wires with an ohm meter. What the white and yellow are for I have no idea? See if they go to those other two yellow wires.

The one big caution mentioned with the PowerBoost is, "don't get your battery polarity backwards". If you do bad things will happen, you will more than likely let the magic blue smoke out and it won't work any more. They mention it because a select few of the aftermarket batteries reverse the polarity on the JST plug. Just to be different I guess?

One thing to check with that battery pack, before you hook up your power boost, is are they in series or parallel. They may be two 3.7V cells but wired in series to provide 7.5V to the tablet. That may be why there are all those wires in the cable. The white yellow charge at 3.7V but the red black supply 7.5V out. Put your volt meter on the red black wires and see what you get. Might even be some components on the other side of that board that you can't see, like the charge circuit. If so, you don't want that there between the battery and your power boost.

I did some more coding on my THP.py file lol. I now have two separate files. One for my portable weather clock and one for the one that stays in the house. All my fancy color changing text washes out in the bright sun. Blue and Red are really hard to see unless you right up close. I found a trick for that though. Blue in my code was (0, 0, b) b=255. I changed it to (a, a, b). If a=0 its blue, but if a=255 its white. I set the joystick up to change from one value to the other. I coded all my color values that way. Now if I click the joystick up, all the colors become white, nice and easy to read even in sunlight. Push the joystick down and I get my custom colors back for when I have my portable out on my deck in the shade of my gazebo. The one in the house I just left as it was. Up down just changes the brightness up down. I think I'm just going to go back to the low_light on off setup I had before. My current way of dimming the display messes up the colors a bit, especially yellow and green. Especially noticeable to me with my partial color blindness. I can't tell the green from yellow with it dimmed. I'm hoping the low_light settings retains the colors. We'll see later on today, just about to take ginger for our morning walk in the woods. =) Talk to you latter.

caperjack said:

good job, I'll never get the coding side of all this Pi stuff

I'm actually starting to enjoy tinkering with my python code. I've had a few WhyTF did it do that moments but I'm learning and it is getting easier to figure it out. I'm sure those skilled in python would look at my code a furl there brows, lol. I don't care though, it works and does what I want. I do most of the editing on my PC. Then test it, and fix it if necessary on the Pi. I just put the file on a thumb drive.

I gave up on trying to get my GPIO wired switch to work. I got the dremel out and made an access hole in my clear cover. now I can easily get a finger in there to access the sense hat joystick. I lost my stop the python file but don't shut down option. I'll just have to do that from a terminal window.
Stick up > low light off.
Stick down > low light on (LED matrix dimmed)
Stick right > all text white
Stick left > test in color mode.
Stick center press > shut down.

Finally got my hands on a couple of CR1220 batteries. Forgot to add them to my last order. The only place that sells them is The Source (aka Radio Shack) and they were out of stock last time I went looking. Bought the last two they had today. Now 3 of my 4 in use Pi's have working dedicated RTC modules. One DS1307 and two DS3231's.

I "think" I'm done messing with my sense hat weather clock python code. For now anyway. The latest file is in my sense hat public onedrive folder. https://1drv.ms/f/s!AjOYwiwlwDtpgUMsp2qnevKpGEHb the THPm file is modified to compensate for extra heat build up in my portable setup. Use the other THP.py file for a setup with no case and or good ventilation and air circulation.

caperjack said:

will give the THPm.py file a try tomorrow night ...

It just subtracts 3 from what the measured temp is. The displayed temp will be 3 degrees C lower than what the sensor measures. I compared what my caseless weather clock showed to what my portable showed. Then fudged it so they both showed the same. Not very technical but it works and its close enough. There is a line that says tc=(t-3) Change the 3 and you change the correction factor. The file with no "m" just shows t with no correction. I've seen some pretty wild formulas on the Pi forum that take into account the CPU temp etc. I'm not going to resort to that unless I have to. have plans to add a small 5v fan to my case and see if that fixes the heat buildup issue. I won't be able to order any more parts for a while though.