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by hampi
Mon Jun 09, 2014 8:09 pm
Forum: Advanced users
Topic: Raspbian Initscript, restart on death?
Replies: 2
Views: 987

Re: Raspbian Initscript, restart on death?

Maybe this helps

Code: Select all

/etc/init.d/skeleton
After running

Code: Select all

update-rc.d mydaemon defaults
you get new symbolic links to different run level directories under /etc/rc?.d/ .

If the daemon hangs for any reason the code needs to be rewritten.
by hampi
Mon Jun 09, 2014 12:43 pm
Forum: Advanced users
Topic: RTS/CTS connection?
Replies: 4
Views: 1347

Re: RTS/CTS connection?

RTS and CTS are, as far as I know, for hardware handshaking, but rarely used today since software handshaking is used instead. Normally you need to connect only RX, TX and GND. In case of problems you can swap the RX and TX from one of the connectors.
by hampi
Sun Jun 08, 2014 4:29 pm
Forum: Beginners
Topic: Auto shutdown on power failure
Replies: 5
Views: 4003

Re: Auto shutdown on power failure

One more to the list https://github.com/oh7bf/RaspiPwr12V How to supply the power in parallel from the battery and mains 12 V PSU is probably obvious to everybody? Basically the switching is done with two power diodes. More delicate question is then how the battery is charged since there are some ri...
by hampi
Thu Jun 05, 2014 5:01 pm
Forum: Troubleshooting
Topic: Pi won't boot, red LED on
Replies: 9
Views: 2486

Re: Pi won't boot, red LED on

I had an interesting experiment about one week ago http://www.raspberrypi.org/forums/viewtopic.php?f=28&t=77840 Basically I could get the RPiA to boot by keeping my finger pressed on SD card socket soldered contacts (not on the card itself). In radio circuits this kind of behaviour would not surpris...
by hampi
Thu Jun 05, 2014 4:29 pm
Forum: General discussion
Topic: My Raspberry Pi won't work
Replies: 6
Views: 827

Re: My Raspberry Pi won't work

MrEngman wrote:So what have you installed? NOOBS? or Rasbian?
Sounds like the initial reading of the SD card fails and thus no boot whatever the RPi system is on the SD card.
by hampi
Mon Jun 02, 2014 4:49 pm
Forum: Advanced users
Topic: measure own voltage through testpoints?
Replies: 8
Views: 2318

Re: measure own voltage through testpoints?

The voltage should be well constant if you are using a proper power supply. However if I would do a circuit like that I would probably use my own PiPIC https://github.com/oh7bf/PiPIC to start with and to get something functional rapidly, and modify the daemon code https://github.com/oh7bf/Tmp102d fo...
by hampi
Mon Jun 02, 2014 12:15 pm
Forum: Beginners
Topic: Assembly Language
Replies: 22
Views: 3784

Re: Assembly Language

A really good programmer can look at the output of a disassembler and see the original 'c' code. Even the assembly code is often made by copy-and-paste of code segments once you have figured out how the elementary things can be done in the machine language and how to present the data in the memory ...
by hampi
Fri May 30, 2014 11:10 am
Forum: General discussion
Topic: Alternative power storage solutions
Replies: 40
Views: 5246

Re: Alternative power storage solutions

What you really need is a solar updraft tower. See the wiki for details

http://en.wikipedia.org/wiki/Solar_updraft_tower
by hampi
Wed May 28, 2014 11:26 am
Forum: General discussion
Topic: An idea for a light switch.
Replies: 11
Views: 1875

Re: An idea for a light switch.

Here is an example of modern LED lights available today http://www.led1.de . Some of these operate directly from 12 V or 24 V DC.
by hampi
Tue May 27, 2014 8:43 pm
Forum: Troubleshooting
Topic: dim ACT light
Replies: 8
Views: 2395

Re: dim ACT light

I was experimenting more the boot problem tonight. My "fix" seems to be to solder a 3 cm long insulated wire both to pin 5 (SCLK) and pin 7 (DATA0). These wires are then twisted together. The RPiA seems to boot with these wires, but without them no boot. The reason behind all this might be a subtle ...
by hampi
Tue May 27, 2014 11:39 am
Forum: General discussion
Topic: An idea for a light switch.
Replies: 11
Views: 1875

Re: An idea for a light switch.

Maybe low voltage LED lights would do? I have an advanced DIY project for that

https://github.com/oh7bf/RasPiPwrSwitch/wiki

but you can make use of only part of the project if doing the complete thing is too much for your time and skills.
by hampi
Sun May 25, 2014 8:44 pm
Forum: Troubleshooting
Topic: dim ACT light
Replies: 8
Views: 2395

Re: dim ACT light

Some interesting results. If I connect the logic analyser (Saleae 20 MHz model) to the SD card slot soledered pins 3 (GND), 5 (SCLK) and 7 (MISO) the boot does happen in my RPiA with 8GB Transcend 10 card. Then after removal of the logic analyser wires no boot anymore. I have no idea if my simple lo...
by hampi
Sun May 25, 2014 6:45 pm
Forum: Troubleshooting
Topic: dim ACT light
Replies: 8
Views: 2395

Re: dim ACT light

@hampi if the card isn't properly connected the same thing happens, try booting with your finger on the back of the card and see if that helps. Thanks for the reply. I tried that already a few times. Checked also the SD card dimensions with a calliper. I can not spot any mechanical problem in my ca...
by hampi
Sun May 25, 2014 4:09 pm
Forum: Troubleshooting
Topic: dim ACT light
Replies: 8
Views: 2395

Re: dim ACT light

I have a similar problem with my RPiA now. It was working for about one month, but now no boot any more. I have three different 8GB SD cards: Transcend 4, Transcend 10 and Lexar 6. They have the Rasbian Wheezy from January 2014 and the Wheezy from September 2013 on the Transcend 4. All of these card...
by hampi
Fri May 23, 2014 2:58 pm
Forum: Other projects
Topic: Yet Another PIC Programmer for the Raspberry Pi
Replies: 21
Views: 8088

Re: Yet Another PIC Programmer for the Raspberry Pi

One more PIC programmer

http://holdenc.altervista.org/rpp/

http://mujweb.cz/tlc/rpp/

and my PCB for it

https://github.com/oh7bf/PiPIC/tree/master/RaspiPICprog

The programmer code is plain C if you like the unix command line interface.
by hampi
Tue May 20, 2014 3:35 pm
Forum: General discussion
Topic: Raspberry Pi shelf life
Replies: 4
Views: 1033

Re: Raspberry Pi shelf life

Soldering of the components is probably lead free now. Maybe tin whiskers could appear on the solderings after some ten years or more? Or this has been solved already?
by hampi
Mon May 19, 2014 11:26 am
Forum: Other projects
Topic: doing the math on solar
Replies: 3
Views: 872

Re: doing the math on solar

I agree that real life can be quite complicated and is rarely described by one simple equation. So there are two possible approaches depending on how big investment the solar operation is likely to be. If you think it is going to be expensive for your budget, then do careful calculations and build a...
by hampi
Sun May 18, 2014 8:23 am
Forum: Beginners
Topic: cooling
Replies: 12
Views: 1593

Re: cooling

Usually the heat sink and optional cooling fan is in the power supply, since that generates some heat depending on the efficiency of the design. Power FETs used for switching might need a heat sink too depending on Rds of the FET and current that is switched. I have these DIY projects in my github i...
by hampi
Mon May 12, 2014 1:03 pm
Forum: General discussion
Topic: Question about running programs when Pi starts up
Replies: 4
Views: 747

Re: Question about running programs when Pi starts up

Daemon coding is not that difficult though needs some care and most of all comprehensible log files.
by hampi
Wed May 07, 2014 9:30 pm
Forum: Advanced users
Topic: Any point to a 2A power supply, given the 1.1A fuse?
Replies: 21
Views: 4236

Re: Any point to a 2A power supply, given the 1.1A fuse?

Well if you want to blow the 1.1 A fuse you need a power supply that can put in a current that is clearly more than 1.1 A. I think a 2 A power supply is a good choise for that.
by hampi
Wed May 07, 2014 5:58 pm
Forum: Advanced users
Topic: Raspberry pi "safe" shutdown
Replies: 6
Views: 2728

Re: Raspberry pi "safe" shutdown

Maybe you can create a script /etc/init.d/ups-monitor and use that to signal poweroff to your hw. My pipicpowerd tries to do something like that, but I am not expert on this field either. In other words it seems to work for me, but that is not a proof that the solution is correct nor that it works ...
by hampi
Tue May 06, 2014 9:03 pm
Forum: General discussion
Topic: Should i get a Raspberry Pi
Replies: 5
Views: 1396

Re: Should i get a Raspberry Pi

Raspberry Pi is addictive. Think twice.
by hampi
Mon May 05, 2014 3:02 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: accessing i2c without i2c-tools
Replies: 6
Views: 2018

Re: accessing i2c without i2c-tools

I know that there are a lot of similar project (for example webiopi), but the goal is building something from beginning and from myself with the purpose of learning something. I do not want to spoil your fun, but I have a small "draft" version of a daemon reading tmp102 with i2c https://github.com/...
by hampi
Sat May 03, 2014 3:46 pm
Forum: Automation, sensing and robotics
Topic: lm2576-5 circuit failing with 13v output
Replies: 4
Views: 3828

Re: lm2576-5 circuit failing with 13v output

These DIY circuits need to be tested before use. You need to have a fuse between 13 V power source and the LM2576. When you connect the power first thing to do is to measure the output voltage. Then you should connect the supply to a load resistor 2 - 5 ohms/25 W and check the output voltage again. ...
by hampi
Fri May 02, 2014 9:03 pm
Forum: Troubleshooting
Topic: Exploding Pi
Replies: 28
Views: 6679

Re: Exploding Pi

ultimatepi wrote:You will have to get a new pi and a power supply.
That is cheap. I would worry more if the house had burned with the RPi. That is by the way one reason why I prefer to switch off appliances before I leave the house.

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