Wikipedia:Reference desk/Archives/Computing/2013 April 17

= April 17 =

Arduino clock coding
I'm trying to get a clock working on an Arduino Uno. I've double checked everything but I can't find what I've got wrong. The code I'm using is taken directly from here. For whatever reason though, the hours and minutes displays just count up to 23 and then reset to 00. They increment once per second. And the seconds display is constantly at 00. I have no idea what could be causing this odd behavior. Can anyone tell me what I'm doing wrong? Dismas |(talk) 02:46, 17 April 2013 (UTC)


 * I would double check that it is reading the set hour and minutes pins properly. I haven't read through all the code in detail, but it looks like what you see could be caused by the setHour function triggering every time through the loop. 38.111.64.107 (talk) 12:08, 17 April 2013 (UTC)

For installing Microsoft Security Essentials' latest update, what IS error 0x8004FF80?
I googled it to find unreplied-to topics about the code. Nothing gets me closer to figuring out how to get around the error so that I can successfully install the update.

I have a gut feeling that some malware caused me to no longer be able to find MSE in the first place, so when I went to download it and got the error, apparently the malware is preventing me from updating. Then it seems the malware cuts out all results showing viable solutions, but at least it can't prevent me from asking you on this refdesk. Thank you for your help. --70.179.161.230 (talk) 10:38, 17 April 2013 (UTC)


 * You may have some luck with this: []. I'm not seeing any definitive explanation of the error in my searching either, but a lot of people seem to be looking it up. The 0x8004 shows that it is a failure with a code specific to the component that created the error, so generic error lookup tools don't help. 38.111.64.107 (talk) 12:01, 17 April 2013 (UTC)

Help with Blender and backgrounds
As part of a short film I am working on, I need a scene with animated characters seeming to interact with a real scene, a background that I have filmed myself. I need some way of setting these characters over this background scene and moving them around in exactly the right way at the right time, however I cannot seem to find how to set a moving image as background or to have it render as part of the final output of the program. There are options within the program for this sort of thing, so I know it is possible, yet somehow whatever I try, I can't get the file into the program or set as the background. any idea what I might be doing wrong?

213.104.128.16 (talk) 15:03, 17 April 2013 (UTC)


 * Have you Googled for tutorials? E.g. this one came up when I Googled "blender background video." It seems more or less to do what you're asking for, no? With Blender, I find one often has to rely heavily on tutorials, because the documentation is obtuse if not non-existent. --Mr.98 (talk) 15:56, 17 April 2013 (UTC)

Find Raspberry Pi on network
Hi all. I'm try to establish a remote connection between my Raspberry Pi and laptop over a wired network that I am not the administrator of. Running "ip addr" on the Pi suggests a local IP allocation of "10.10.23.128/22". I have tried searching both that particular IP and the range from my laptop using nmap -- the particular IP is down; I find lots of other computers attached to the network over that range, but not the Pi. If I run "ip addr" from my laptop, I get 10.10.23.60/22 and it can find itself at that address (or it seems to, anyhow). Both can connect to the internet fine, so they must both be having no trouble accessing the network. What am I doing wrong? There's probably a really simple answer, but this all worked nicely on a different network that I am the administrator of :/ (It's possible that the administrator of this network is blocking requests somehow, but as I say, I can see other PCs attached to the network.) Thanks in advance, - Jarry1250 [Vacation needed] 19:34, 17 April 2013 (UTC)


 * It's possible that the ethernet switch is set to maintain multiple VLANs. It may be doing that based on physical port (network socket on the wall), on MAC address (e.g. untrusted or unknown MAC get put into a "guest" VLAN), or on any number of other reasons the network administrator may have chosen.  As you've already determined on your own network, a Raspberry PI running say Debian isn't substantively different from any other Linux machine (its MAC should begin B8:27:EB). You may have to talk to the switch administrator. -- Finlay McWalterჷTalk 19:53, 17 April 2013 (UTC)
 * The VLAN by MAC sounds plausible (the Pi's does indeed begin with B8:27:EB), thanks. If there are no other suggestions I guess I'll have to email.. - Jarry1250 [Vacation needed] 20:10, 17 April 2013 (UTC)


 * In particular, they may have rules that say "machines on physical ports A,B,C, and D are routers, servers, printers, etc. - so they can send to, and be sent to, by everyone; every other machine doesn't see any traffic other than from A,B,C, and D". That way they can stop normal clients seeing one another at all, so people don't inadvertently advertise services like file sharing to one another, mess the network up by accidentally running their own DHCP server, and one guest machine that's infected by a rootkit which tries to probe the localnet for more victims can't see anything but machines that are properly administered by someone who knows what they're doing.  If this is the case, all the machines your nmap scan will report should be these kinds of things, and not someone else's laptop. Filtering by physical port rather than MAC address is more robust (because it can't be spoofed). -- Finlay McWalterჷTalk 20:33, 17 April 2013 (UTC)
 * The 128 at the end of the ip is a bit worrying - perhaps it is on another subnet or you have it masked out in your subnet mask? Or perhaps 'over that range' covers this possibility. Dmcq (talk) 20:39, 17 April 2013 (UTC)
 * What's special about 128? The /22 part is CIDR notation, and both of these addresses are in the same CIDR subnet. -- Finlay McWalterჷTalk 20:57, 17 April 2013 (UTC)
 * Sorry yes I misunderstood. That seems a lot of devices and I was really just saying I would definitely expect the two devices to be on different network switches even if they are trying to make them look like they are all on the same subnet. Dmcq (talk) 00:02, 18 April 2013 (UTC)
 * Have come around to that they probably are implementing VLANs as the first responder said. Dmcq (talk) 10:10, 18 April 2013 (UTC)


 * Have you tried running "/sbin/ifconfig" on the Pi? You don't have to be admin to query ifconfig (but do to make any changes). That should list the address that it has been allocated by DHCP. -- CS Miller (talk) 20:11, 18 April 2013 (UTC)