A Comcast customer who is dissatisfied with Internet speeds set up a Raspberry Pi to automatically tweet at Comcast each time speeds are much lower than advertised.

"I pay for 150Mbps down and 10Mbps up," Reddit user AlekseyP wrote over the weekend. "The Raspberry Pi runs a series of speed tests every hour and stores the data. Whenever the down[load] speed is below 50Mbps the Pi uses a Twitter API to send an automatic tweet to Comcast listing the speeds. I know some people might say I should not be complaining about 50Mbps down, but when they advertise 150 and I get 10-30 I am unsatisfied."

AlekseyP made the Twitter bot's code available on Pastebin. "I am by no means some fancy programmer so there is no need to point out that my code is ugly or could be better," the Redditor wrote. AlekseyP set the tweeting threshold at 50Mbps in part because the Raspberry Pi's Ethernet port tops out at 100Mbps.

The Twitter account controlled by the bot has tweeted speed test results 16 times in the past three months, often getting replies from Comcast customer service.

Speeds were at their worst on New Year's Day when they dropped to 2Mbps:

"Plenty of the drops were during hours when we were not home or everyone was asleep," AlekseyP wrote.

Of course, no consumer broadband service hits advertised speeds 100 percent of the time for all customers. Speeds are generally advertised as "up to" a certain Mbps. Comcast says on its website that "Actual speeds vary and are not guaranteed."

If AlekseyP's Raspberry Pi has been running hourly speed tests and only found lower-than 50Mbps speeds 16 times in three months, that would mean actual speeds are 50Mbps or above more than 99 percent of the time.

AlekseyP has rebuffed efforts by Comcast customer service to gather more information. "Comcast has noticed and every time I tweet they will reply asking for my account number and address... usually hours after the speeds have returned to normal values," AlekseyP wrote. "I have chosen not to provide them my account or address because I do not want to singled out as a customer; all their customers deserve the speeds they advertise, not just the ones who are able to call them out on their BS."

One Redditor who works as a field technician for Comcast posted a detailed reply to the thread, saying that a few things could cause speed drops, including radio frequency interference, a damaged cable, or a bad modem. Another Comcast employee, VP of Internet Services Jason Livingood, detailed some potential flaws in AlekseyP's testing methodology.

AlekseyP did write in a comment that performance has gotten better recently. "I set this up because I was frustrated during a period of constant drops and outages. It is a lot better now. We used not be able to stream Netflix and I would fail to connect to CSGO [Counter-Strike: Global Offensive] matches," AlekseyP wrote.

Comcast better than most ISPs in FCC test

The Federal Communications Commission evaluates whether Comcast and other large ISPs consistently deliver advertised speeds in its annual Measuring Broadband America study. The latest report, based on tests in September 2014, shows that Comcast's slower speed tiers (from 3Mbps to 50Mbps downloads) were on average delivering download speeds higher than advertised during peak usage hours.

At Comcast's 105Mbps tier, the cable company was delivering 94.6 percent of advertised speed during peak hours.

Average speed across all customers isn't the only important measure, because some subscribers could be getting much slower speeds without bringing the average down much. More than 90 percent of Comcast customers got at least 95 percent of advertised download speeds in the FCC measurements. A few percent got between 80 and 95 percent of advertised speeds, while about 5 percent were getting less than 80 percent of advertised speeds. In this measure, Comcast outperformed most ISPs:

Despite that, there are a decent number of Comcast customers who pay for higher speeds but aren't consistently getting them, as the report showed that Comcast often struggled to match advertised speeds for 105Mbps customers: