At a time when its approval rating is struggling to break 16 percent, Congress has a desperate need to prove it's accomplishing something. To that end, all manner of tools have been created in recent years to connect voters with lawmakers. It's like the Holy Grail of civic engagement: Letting Americans participate in the process of legislating helps generate sympathy for those bickerers on Capitol Hill — or something.

Now there's another entrant in this space: Capitol Bells, an iPhone app that lets constituents "vote" on legislation alongside their representatives. Unlike other attempts at bringing transparency to the legislative sausage factory, this one works in real time. And crucially, it could prove as useful to lawmakers as to voters.

(Ted Henderson/Capitol Bells)

Ted Henderson is the developer behind the project. Until January, Henderson was a staffer for Rep. Dale Kildee, a Michigan Democrat. When his boss retired this year, Henderson spent the next seven months coding an app to help new staffers become accustomed to Congress's unique buzzer system that indicates when votes are happening.

"When a vote happens," said Henderson, "there are a series of buzzes and lights in different patterns according to what's going on. You have to understand what the patterns are to say, 'Oh, is that a recess call or a quorum call?"

By installing a radio receiver close by to tap into that signal and translate it, Henderson physically linked his app to the buzzer system. Whenever it goes off, it triggers a notification in the app.

At first, that's all it really did. As an app built by a staffer, for staffers, there wasn't a need for much more. But last week, Henderson built in a feature that allowed users to associate themselves with a particular district, and to cast "votes" on the same legislation that their congressional representatives were voting on.

"Five or six days ago, all the users were Hill users," Henderson told me. "Now over half are members of the general public."

Even those new users are mostly based in Washington. Still, the developer is focused on a bigger goal: Aggregating a district's unofficial voting patterns and correlating them with a member's actual voting record. Eventually, lawmakers will be able to gauge how well they're representing their most engaged constituents by looking at differences in the last 20 or 30 votes, said Henderson.

Capitol Bells already has admirers in Congress. House Minority Whip Steny Hoyer (D-Md.) and Rep. Jared Polis (D-Colo.) have both endorsed the app in recent days.

"My staff and I use Capitol Bells to make sure that I don't miss important votes," said Polis. "I'm excited that now Capitol Bells will be offering another way for my constituents to communicate with me and other members of Congress about their views on legislation in real time, as votes are happening."

Having buy-in from actual Congress members could make all the difference for Capitol Bells. Other tools, like, operate on an upvote system where the most popular bills rise to the top of the site. In other words, it's a good triage system. But the information that this provides to lawmakers isn't nearly as specific to their needs as what Capitol Bells provides. It's not broken down by state or district, and it doesn't tell you whether voters want the bill passed or killed.

"When the bell goes off, everyone stops what they're doing," said Henderson. "Looking at [existing] Congress apps, I was kind of surprised. Nobody had that basic function of, 'there's a vote happening.'"

So he built it.

Update: I've gotten a few readers asking whether Henderson plans to support Android phones anytime soon. The answer is yes. In fact, the developer's launched a crowdfunding campaign to raise money for it. With 17 days left to go, Henderson is 13 percent of the way to his goal. He said he wants to launch the Android app in time for Congress to return from summer recess on Sept. 9.

I've also gotten new information from Henderson about his user demographics. While DC is still in the top five districts for number of "voters" using the app, TX-25 has the most "by far." Other districts in which Capitol Bells is popular include TX-31, WA-10 and CA-24.