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by achrn
Thu Feb 20, 2020 6:01 pm
Forum: General discussion
Topic: framebuffer_depth=24 breaks X
Replies: 2
Views: 134

framebuffer_depth=24 breaks X

It seems that framebuffer_depth=24 in /boot/config.txt breaks X (quite conclusively - it decides there are no screens available and refuses to run) in the 13/02/2020 raspbian buster. That's just taken me about five hours to track down. Is this a known issue? Will it be fixed? Or is it the way it is ...
by achrn
Tue Feb 18, 2020 10:29 am
Forum: General discussion
Topic: Powering Pi Zero with AA batteries
Replies: 25
Views: 708

Re: Powering Pi Zero with AA batteries

Definitely go for a buck converter that are recommended for SBC projects: https://www.adafruit.com/product/2190 https://www.piborg.org/power-1137/battborg That adafruit one is a buck-boost, so significantly less efficient than a buck converter, and it's only good for 1A and costs 10 USD. The piborg...
by achrn
Mon Feb 17, 2020 10:22 pm
Forum: General discussion
Topic: Powering Pi Zero with AA batteries
Replies: 25
Views: 708

Re: Powering Pi Zero with AA batteries

Easiest way is to use 6xAA and one of these: http://www.astounding.org.uk/ian/raspi-ups/UBEC.jpg

Search ebay for 'Hobbywing 3A UBEC'. About £5 if you buy one already in the country. Cheaper from China. Four cells won't quite be enough though, so you want six or preferably eight cells.
by achrn
Sun Nov 03, 2019 7:38 am
Forum: General discussion
Topic: Recover root password, NOT!! reset password
Replies: 20
Views: 2679

Re: Recover root password, NOT!! reset password

How do I RECOVER the root password? I can NOT reset it as the whole system uses the same root password so it won't work. What does this mean? What 'whole system'? If you mean the whole of the Pi, that's fine - most (if not all) of it will get the same password from the same place, so you change it ...
by achrn
Thu Oct 24, 2019 1:45 pm
Forum: General discussion
Topic: Trying to measure current going into Raspberry Pi
Replies: 6
Views: 638

Re: Trying to measure current going into Raspberry Pi

If you are tinkering a lot like me, I can alternatively recommend such a module: https://www.ebay.com/itm/DC50V-5A-Digital-Constant-Volt-Programmable-Power-Supply-Module-DPS5005/253214845194 I use to power it from a salvaged laptop PS adapter delivering 19V/4A. (you may also use two in series if yo...
by achrn
Tue Oct 15, 2019 11:01 am
Forum: General discussion
Topic: Raspberry Pi Solar-Powered: Great OnLine Tool
Replies: 8
Views: 660

Re: Raspberry Pi Solar-Powered: Great OnLine Tool

Leisure batteries (sold for caravans, for example) are a better buy for this purpose. Are they not less common and hence more expensive at same capacity? Less common yes. More expensive for the stated nominal capacity, yes. The point is they are less expensive for the useful capacity, because you'l...
by achrn
Thu Aug 15, 2019 12:22 pm
Forum: General discussion
Topic: PoE Power
Replies: 2
Views: 188

Re: PoE Power

A full standards-compliant PoE injector won't send power to a device that isn't standards-compliant (or nearly so), so in that case nothing bad. A passive injector that just imposes voltage on the wires regardless, I don't know - there are still lots of variables. The voltage is clearly a variable (...
by achrn
Tue Jul 30, 2019 2:12 pm
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 945
Views: 127972

Re: Raspberry Pi 4 Thread - general discussion

I could add all that up for you, but I think you are smart enough to see its surly not free. Why not claim you need to buy a house to keep the Pi in so you can use it when it's raining? That would make about as much sense as the claims you're making, and then you could say that a Pi costs hundreds ...
by achrn
Fri Jul 05, 2019 12:03 pm
Forum: General discussion
Topic: RP4 without ESD protection shipped
Replies: 15
Views: 985

Re: RP4 without ESD protection shipped

Ignoring ESD is not professional, it just a stupid way to invest a lot of time to find strange errors. So, when you read "It uses a specially conductive material to prevent ESD damage" and "The boxes have a conductive coating", you understood that to mean "we just ignored ESD"? Presumably you've te...
by achrn
Thu Jun 27, 2019 11:47 am
Forum: General discussion
Topic: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case
Replies: 66
Views: 24790

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

I'm actually pretty worried about the Flirc Case. I pre-ordered the new case for the rPi4 and I'm not sure it's going to be enough. ... I'm not sure if the extra mass is going to be enough by itself. But, I'm not a hardware engineer, so I don't really know. It's not the mass that helps, it's the su...
by achrn
Sat May 04, 2019 8:19 pm
Forum: General discussion
Topic: Power fans to cool Rpo 3B+
Replies: 6
Views: 476

Re: Power fans to cool Rpo 3B+

I have read in several places that's a bad idea to plug a fan to the rpi pins (at least directly). How could I power those fans? I guess I need an extra power supply for them. You can't run a (useful) fan on the actual GPIO pins directly, but there are power pins in among the other header pins on t...
by achrn
Fri Apr 26, 2019 3:05 pm
Forum: General discussion
Topic: Will Arduino nano and RPI get Damaged on Supplying 5V 3A DC?
Replies: 29
Views: 1569

Re: Will Arduino nano and RPI get Damaged on Supplying 5V 3A DC?

I happen to have a bunch of 5v 4A power supplies, so this is what I typically use, even for just a Pi alone. Ok, So I can Provide it 5.1V and 3 or 4A. Can you Please Show me your schematic for making 5V 4A Power Supply? He says he has a bunch of 4A power supplies, not that he made his own power sup...
by achrn
Thu Apr 25, 2019 12:39 pm
Forum: General discussion
Topic: resolv.conf automatically deleted from etc in raspberry pi 3
Replies: 6
Views: 374

Re: resolv.conf automatically deleted from etc in raspberry pi 3

Files looking OK until the system reboots and then either disappearing or reverting to a previous version is a bad SD card, in my experience. It doesn't have to be fake - genuine but faulty will do it too. I've had this a few times (I had one Pi that was prone to making cards do it, but I've scrappe...
by achrn
Thu Mar 28, 2019 2:09 pm
Forum: General discussion
Topic: How long will it stay on with a external battery?
Replies: 33
Views: 1966

Re: How long will it stay on with a external battery?

20100 / 500 = 40.2 hours You're assuming this battery outputs 5V. If it doesn't, your trivial calculation is clear, simple and wrong. OP: We need more detail, like: 1: Do you really mean battery, or do you mean powerbank? 2: If battery, what chemistry and what voltage (or how many cells)? 3: Is it ...
by achrn
Sun Mar 10, 2019 5:26 pm
Forum: General discussion
Topic: LiPo Battery Voltage Drops
Replies: 7
Views: 537

Re: LiPo Battery Voltage Drops

If you're trying to draw 0.7A, you'll be taking 0.7 x 5.2 / 3.2 / 0.85 = 1.3A from the battery (if we assume an 85% efficiency) I was hoping to get some math for my setup. Since I would like to read up on the theory (I am quite uneducated in electronics), could you point me to some sources? A switc...
by achrn
Sun Mar 10, 2019 8:17 am
Forum: General discussion
Topic: LiPo Battery Voltage Drops
Replies: 7
Views: 537

Re: LiPo Battery Voltage Drops

This setup draws around 0.7V, Is that supposed to be 0.7A? If I only connect the RasPi without Display the system boots up, drawing around 0.2A. Where? From the battery, or from the powerboost? Presumably from the powerboost (ie into the Pi) , so (given that you've told us it's dipping below 3.2V) ...
by achrn
Sat Mar 09, 2019 2:45 pm
Forum: General discussion
Topic: Under voltage detected - revisited
Replies: 26
Views: 1995

Re: Under voltage detected - revisited

Anyhow, I still don't understand the purpose of diode D1 on the expansion board. It may very well be drawn wrong. That block is just input filter and protection for the board, specifically D1 is so if you connect your power supply backwards (relatively easy to do with screw terminals), you won't da...
by achrn
Fri Mar 08, 2019 9:19 pm
Forum: General discussion
Topic: Under voltage detected - revisited
Replies: 26
Views: 1995

Re: Under voltage detected - revisited

take the Pi off the board, connect a (say) 10 ohm resistor between pins 2 and 6 on the board GPIO jumper (just poke the resistor wires in the holes) and measure the voltage across the resistor. It will be drawing 0.5A but should still give you 5V. It occurs to me that I should point out (in case it...
by achrn
Fri Mar 08, 2019 4:09 pm
Forum: General discussion
Topic: Under voltage detected - revisited
Replies: 26
Views: 1995

Re: Under voltage detected - revisited

Possibly the schematic is not quite true, and the board is putting the 5V supply to the board through D1 before passing it to the Pi, so your Pi is actually getting 5.02V minus a diode drop. I am not seeing that. I think you are looking at it backwards. To me it looks like you plug the Pi into this...
by achrn
Fri Mar 08, 2019 12:40 pm
Forum: General discussion
Topic: Under voltage detected - revisited
Replies: 26
Views: 1995

Re: Under voltage detected - revisited

Because the 5V are fed through the rpi 5V pins and not trough its USB port, I'm not sure if it's the reason of the following messages: I don't believe it is. If anything, you'll get lower voltage by feeding to the usb than feeding to the GPIO header, since the latter bypasses some protection ciruci...
by achrn
Tue Mar 05, 2019 8:17 pm
Forum: General discussion
Topic: RPI 3 B+ running on Battery 200mAh
Replies: 21
Views: 1084

Re: RPI 3 B+ running on Battery 200mAh

I don't think I've seen a PP3 that can give you 600mAh at 200mA - you only get those sorts of capacities out of that sort of battery if you're drawing only 1 or 2 mA and/or only for an hour a day with long recoveries in between. (Indeed, the data sheet cited shows 2mA for 300 hrs (to 6V) = 600 mAh,...
by achrn
Tue Mar 05, 2019 4:08 pm
Forum: General discussion
Topic: RPI 3 B+ running on Battery 200mAh
Replies: 21
Views: 1084

Re: RPI 3 B+ running on Battery 200mAh

Well, I looked up the datasheet for my particular battery: https://d2ei442zrkqy2u.cloudfront.net/wp-content/uploads/2016/03/MN1604_6LP3146_US_CT1.pdf I didn't see where it talked about a maximum output current, but it does show a particular chart of interest to me at 200mA ( 1000mW ? ), because it ...
by achrn
Sun Mar 03, 2019 9:47 pm
Forum: General discussion
Topic: Weatherproof Enclosure...
Replies: 4
Views: 537

Re: Weatherproof Enclosure...

I had problems with a Pi in a plastic box in an ambient of a little over 50C. I've now done this: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=217627#p1431981 and it looks fairly promising, but I haven't had it in the high ambient conditions yet. Most of the Hammond cases can be had with ...
by achrn
Fri Mar 01, 2019 2:21 pm
Forum: General discussion
Topic: Layout of new official keyboard
Replies: 47
Views: 3251

Re: Layout of new official keyboard

>> Ah yes, I do like a keyboard with out the stupid redundant num pad. I've found that accountants like them - they can bash numbers in quicker than on the horizontal keys. But why do the rest of us get lumbered with them just because one teensy tiny part of the workforce wants them? In my company ...
by achrn
Fri Mar 01, 2019 10:14 am
Forum: General discussion
Topic: Operating 24/7
Replies: 15
Views: 2429

Re: Operating 24/7

Yes, 24/7 is fine. My first Pi has been running basically 24/7 since mid 2013 (though it generally doesn't get much more than a year uptime at a time, because it's on my central heating, and that occasionally gets switched off for things like boiler servicing - right now uptime is 127 days, that shu...

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