A while ago I wanted to remove some pages from a PDF file. I was searching for tools to do that, but I didn’t find a solution. A few weeks ago I stumbled upon this blog post: Merge multiple PDF files into one file. There G33kgrrl describes a few of pdftk‘s functions. But it has quite a lot more functions. Read the manual to see what else it can do.
I hope I will remember this blog entry the next time I have to manipulate a PDF file
Today I wanted to download a few standards documents, about 15 PDF and ZIP files. But this stupid webserver always just sent between 100kB and 700kB, then it completely stopped sending data. This was annoying me. I wanted to look into these documents.
wget has a nice
--continue option. This way I can hit CTRL+C and continue. repeating this until I have the whole file. But this is too cumbersome when downloading many and/or big files. I wanted a completely automated way to do that. And there is one,
wget has many more options. Keep retrying forever and set the read timeout to 3 seconds:
wget --continue --tries=0 --read-timeout=3 URLS...
Tadaa! It downloads everything, problem solved
Today I fixed my battery light. I changed R15 to 39k, and for R14 I had used 33k since I didn’t have anything between 22k and 33k. The threshold voltage is now at most 7.3V so this rubbish wire can make a voltage drop of over 4V and it will still work. And just for testing I’ve put a 470uF cap instead of the 100nF for C5. I left this one inside, it makes a nice delay for the LDR just in case some stray light hits it. Here is the updated schema (more docs).
Now I’m happy with it. Except maybe I add a sleeping mode where it makes just enough light to see the walls, or adding a wire to the bathroom and putting a PIR sensor and an LED there, or …
Why use an Arduino? Why don’t you build your own PCB like I do?
This way you decide which AVR pin is used for what and how you layout your own PCB. And you can save a lot of money. On the other hand you have to invest some time to build it.
Today I finished version 2 of my battery light circuit: