Leon's Weblog

May 20, 2011

Designing an HTPC (part 2)

Filed under: Gadgets,Personal — Leon @ 11:18 am

This is the second part of the article on designing an HTPC. In part one, I described the hardware components and assembly steps that I used to build the device. Without the proper software and media, however, all you have is a pretty box that consumes power. In this part, I will revisit some of the design requirements that were discussed in part one and review the software that will make the magic happen. Although many of the tools listed are available for both Windows and Linux systems, I will describe the Windows editions (simply because getting the drives setup for all the hardware selected in part one can be a pain under Linux). Also, while the built in Windows Media Center may have some of the desired functionality it is often not the best choice available. (more…)

May 13, 2011

My Roomba

Filed under: Gadgets — Leon @ 1:46 pm

I have been using the Roomba 560 model for the past year and am generally pleased with its performance in my apartment. It took a few tweaks and adjustments at first but my Roomba and I have learned to get along quite nicely. The initial problems were solved by simply removing some obstacles on the floor and closing closet doors where the Roomba may enter and get stuck. The other solutions involved a bit more tinkering.

Cliff Sensors
I have a small dark area rug in the living room and the Roomba simply refused to clean it. It turns out that this is a common problem. The cliff sensors which are designed to prevent the vacuum from falling down the stairs are triggers by dark surfaces. I had to disable the sensors to fix this problem (this wasn’t a problem for me because I don’t have stairs). The options for disabling the sensors range from the elaborate but elegant solution of taking the sensor apart to turn it off to simply covering/taping up the 4 sensor externally with glossy white paper. I preferred the latter approach.

After a few months, the lighthouses (virtual wall) stoped working properly. Sometimes a lighthouse would unexpectedly turn into a virtual wall (stopping the Roomba from going into some rooms) and other times the lighthouse wouldn’t turn on or block the Roomba at all. I tried resetting all the virtual walls by taking out their batteries and turning off the Roomba (holding down the “Spot” and “Dock” button for at least 15 seconds) but that didn’t fix it. It turns out, the virtual walls like having fresh batteries to operate properly…

Battery Life
After about 6 months, the Roomba started acting a bit sluggish. It would need to go back to the base to re-charge before finishing cleaning the entire apartment. At one point a full charge would only last it about 30 minutes of operation. None of the resetting tricks worked so I called iRobot and was told that this is a known problem for this series. They sent me a new battery and a kit to upgrade the Roomba’s battery charging logic to prevent the problem from occurring again. So far so good. I was also told by customer service that this problem tended to happen when the Roomba was not used often enough (so the battery would overcharge).

Error 9
After about a year, the Roomba finally had to go on disability. It would erratically stop working and announce the dreaded “Error 9.” Roomba support documentation mentions that this error indicates that one of the bumper sensors is stuck or dirty. Unfortunately it can also indicate that the sensor burned out (as it was in my case). Luckily this is a common enough problem that some DIY engineers took to fixing it and one of them was nice enough to post a guide. This is a $2 fix if you do it yourself. (It looks like the guide no longer shows where to get the parts… I used Sparkfun.com)

Overall, I still think that maintaining the Roomba beats manually vacuuming and recommend it to anyone lazy enough to try.

Update 06/04/2013
After about 4 years of use, my Roomba has died once again. I called tech support, it was determined that the problem was again with the battery. Based on other user comments it seems like 2 years is the average lifespan of the Roomba battery so I guess this was to be expected. I ordered a new battery from iRobot and got a 15% discount as this was my first order of an iRobot accessory. I thought this was a good deal until I found a generic Roomba battery on Amazon for 1/3 of the OEM price. I would expect the generic battery to be of a lower capacity and quality (you get what you pay for) but it still makes more sense to replace a cheap generic battery every year than the expensive OEM model every 2 years.

The tech support guy tried to get me to upgrade to a newer model (at a slight discount) but I didn’t think it was worth it. Especially when you can upgrade the dust bin to the latest AeroVac model (with new brushes and filters) for only $70. I think it makes a big difference in the amount of dust that the Roomba picks up and make cleaning the vacuum a bit easier (single compartment bin). For some reason, this upgrade kit was only available in white in the iRobot store but I found the same 500 Series Upgrade Kit available in black on Amazon for the same price (with free shipping).

Finally, after messing around with glossy paper for a few months to cover up the cliff sensors (see above), I finally decided to take the cliff sensors apart to permanently disable them (see link above). Yes, this does void the warranty but the method demonstrated in the guide can always be undone and it really is much neater. After a while the paper taped over the sensors gets dirty and falls off requiring additional maintenance that I decided to avoid.

Update 06/05/2013
The Roomba had another operation today. After charging the Roomba directly from the external connecter (to charge a new battery), I noticed that the Roomba stopped charging when placed back on the base (with the external connector unplugged of course). It turns out that this charge connector on the Roomba has a tendency to break. The problem and fix is demonstrated here and here.

The problem is that the charge connector has a switch in it to detect when the Roomba is plugged in and this switch prevents charging from both the external connector and the home base at the same time. In fact, the Roomba won’t even return to the base station (i.e. dock) because it “thinks” that it is plugged in. Before going through the extreme measure of drilling the connector open to fix the switch (as illustrated in the fix above), simply try to use a thin screw driver and pull the flat metal lead towards the center pin of the connector (externally… opening no dis-assembly required). This may work for a while until the lead gets loose from vibration (at which point you may have to resort to the drastic measures illustrated… or order a replacement part on digikey.com for under a $1)