How I Built an Apartment Buzzer for Multiple Roommates | Hacker News Reader

How I Built an Apartment Buzzer for Multiple Roommates

daniellemorrill.com

132 pointsdanielle1735 comments

full disclosure - I work on Twilio, which I used for this

I love Twilio, let me count the ways. Doing flow control of an online or offline process from a phone is awesomely powerful. (Particularly cell phones.)

Here's a related example which I'm busy coding today: I wanted people to be able to record custom appointment reminders, but (following many years of supporting non-technical users) think microphones and MP3 encoding are probably beyond their ken. So instead, when you click "Send Mary Smith a custom reminder" on the site, it pops up a lightbox saying "Call 555-123-1234 and type in the code 1234", and when you do so the phone will say "Leave your custom message for Mary Smith's appointment on June 16th from 5:00 PM to 5:30 PM after the beep." Then, after doing so, your lightbox automatically closes and you get visual indication of success.

Bonus points: registering new numbers in Twilio is so cheap that I can trivially afford to give every customer their own call-in number, and tell them to put it on speed dial. Then I can use the same basic pattern for any number of tasks.

You've still got the user interface backwards — you shouldn't have to present a dialog with a phone number for the user to dial, your app should simply call the user when they click a button.

Amazon does this as a confirmation step when you sign up for AWS, and most of the interactions in Google Voice are based on this model.

Awesome idea. Do you have a link to this? Would be cool to see it.

http://www.appointmentreminder.org for the service. Should launch publicly in July. I will disavow all knowledge of comments about forthcoming features should priorities change during development ;)

This is really cool! When I was in the roommate situation, we just posted buzzer codes composed of dots & dashes next to each name.

I love how the top story on Hacker News reminds me that I owe Danielle an e-mail after TC Disrupt to get myself a Twilio t-shirt. :) waves at Danielle

waves shipment goes Wednesday, make sure to get your address to me before then

Since they're using Twillo, it now costs $0.03 to enter your apartment plus $1 per month for the phone number.

Food for thought. Does anyone know if Twillo does sub-one-minute billing?

Nope, Twilio doesn't do fractional billing.

I can report back on how much it costs me to run this thing after a month. With 5 people coming and going average of 2 times per day each, I expect it is going to come out to around $0.30 per day x 30 days plus the $1/mo for the phone number -- so roughly $10/month... we'll see how close my guess is

Wow, that's extremely cool. I remember checking Twilio out before, but I didn't quite get what the use case might be for it. This example has managed to flick on a light switch in my head, and I see that with a platform like this you could build some amazing applications. I will be playing with it more in the future.

full disclosure - i work on Twilio, which I used for this

Danielle- hopefully it's just a coincidence, however I emailed you exactly this idea (and outlined the implementation almost exactly like you just did) about a year ago (our email conversation about it began on 7/7/2009; we met prior to that at the GigaOM VIP party).

I hope that it's not a coincidence. A pretty neat idea was provided for nothing a year ago and has been doing nothing but sitting around in the two of your heads. Danielle brushed the dust off, executed, and shared the results.

What did you do with it?

I'd say this is a timely example of the "Ideas are worthless. Execution is everything." mantra from just the other day.

That frequently regurgitated phrase means that execution matters more than an idea for a business, not that ideas are literally worthless and therefore undeserving of attribution.

Do you normally send people ideas you hope they won't implement?

I was a really early Twilio adopter, and was having issues with it (since it wasn't nearly as good as it is now). I emailed her a support question, and she asked me what I was doing:

"I'd be interested to talk with your more about what you're looking to do with sendDigits/DTMF tones on incoming calls, this might be something we should consider adding in the future."

So, I outlined my entire system to her. I have no problem with someone using my idea- however, she was answering a private support issue that I (a paying customer) had, and I was helping her by providing her with more information about what I was doing with her system.

Then, she posted it on her blog without crediting me. Implementing the idea isn't bad; posting a private support thread as your own idea on your own blog, however, is.

I'm sorry I had no idea I was ripping you off, I appreciate that you're a Twilio early adopter. Like you mentioned, I handle customer support for Twilio and hear about countless ideas, feature requests, etc. everyday. There's no way I could remember who came up with what, and multiple people run similar ideas by me all the time.

I built this to scratch my own itch and its also a really simple use case to illustrate the ability to control real world devices with DTMF tones. Some Twilio projects I had in mind when I built this include Buzzeromatic.com, which is also powered by Twilio and costs $1.95/month and had a very public launch. Sunlight Labs also did a door hack with Twilio and an arduino that I thought was pretty sweet.

What I think is important is that what I've built doesn't have any UI or anything like that, just a really stripped down version and I'm not looking to make it into some paid service. You could certainly take these guts and turn them into a kickass product, but these <100 lines of PHP are not the defensible secret sauce.

The ability to use DTMF tones with Twilio has been around for awhile, I got the tone generator from a Get Satisfction thread that's about a year old: http://getsatisfaction.com/twilio/topics/dtmf_tone_generatio...

Sorry, I didn't mean to pick a fight, I just knew we talked about the exact same implementation a long time ago :)

Keep up the great work with Twilio- I use it on as many of my projects (such as http://getdoorman.com, my commercial door buzzer app and http://pleasecallmyphone.com) as I can.

This idea is too obvious to stake any sort of claim. And once you've decided to do it, there aren't many variations on the theme.

Basically anyone who has programmed with VoIP and has a callbox has thought about or done this. E.g., I did this years ago using a VoIP server that I wrote -- silly prompt sounds and all.

Furthermore, companies like Twilio are seldom surprised by applications of their platform; they likely had to come up with tons of examples for investors when they raised money.

Ok, next time could you indicate that you use a restricted service in you headline so those of us who can't get Twillo can skip reading about it?

One could always just use a Twilio equivalence in your country. Twilio might look easy, but it's just as easy rolling your own with something like Adhearsion. Just sign up for some cheap origination/termination services and you're ready to roll your own twilio service. I use iCall for origination & VoipJet for termination here in the US; my asterisk & adhearsion stack runs on a small cloud server at rackspacecloud.

Any other disclosures I should add about my startup? Oh, you have to pay for the API too... OMFGBBQAFKBFF4EVA

we are working on international support, stay tuned

International support isn't the issue, the issue is that you won't let non-americans sign up.

And yes, I am running a vendetta against discriminatory start-ups. The internet doesn't care about borders and if you do, you don't deserve to be on it.

The internet

time to write a blog post about this... these "vendettas" from people outside the U.S. against startups that won't let you sign up so annoying. Maybe you should channel all that energy towards convincing your own country to make it easier for us to operate businesses within your borders... the limited resources of a startup have to be carefully spent, and thinking about foreign exchange, taxes, and laws (especially on stuff like telecom) is not a small undertaking

Oh, the awesome possibilities you can create with Twilio API. =)

Archive of twilio contests, looking at these can be useful to generate new or related ideas. http://contests.twilio.com/archives.html

What are the chances that Twillo will take an Uzi to it's API users ?

http://twitter.com/cdixon/status/14636556473

Considering that Twilio is purely a platform company (even more so than Amazon Web Services, since they primarily have an online store to run), this seems very unlikely if not entirely impossible.

I would be surprised if you said otherwise, considering you're a Twilio employee.

hey progrium they do disclosures around here, stop coding and update your profile =)

Nice usage!

At my place, I have a group ("Gate") set up in Google Voice which forwards the number to my cell phone and if I can't access my phone, then the custom voicemail that caller hears is the DTMF key ("9" in my case) sound and so if I am not able to get the phone, it will automatically buzz them in.

So anyone who dials your apartment gets through the gate?

This is a bit late.. but yes, anyone who dials me (and if I do not answer the call will be able to enter). If I do answer the call, I can just end it without pressing "9" to make sure they cannot get in. Since my T-mobile connection is spotty, I would rather not have my guests stuck outside and am willing to take the risk (although a persistent criminal would be able to enter the complex anyway).

No, only the people dialing from numbers he's added to his "Gate" group in GV.

The way these systems usually work, the call comes FROM the keypad/speakerphone at the gate, TO your home number. That's how it can recognize the DTMF and open the gate.

If the call were coming FROM his friends mobiles, TO Google Voice, how would the gate intercept the DTMF? Note that he says the group includes "the number," not "the numbers."

The original article states that it is possible to set up a system this way, such that anyone who calls gets in, but it is insecure.

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