How to build a one-button recording device for interviews

If your looking for a digital voice recorder. I'd say just buy one. Buying a mass produced product is going to be cheaper than if you buy the single peices yourself. Also, they have been extensively tested and reliable. If you want a voice recorder with digital memory and USB you can buy a decent one with about 70hours of recording time for 35 dollars. If you want something cheaper they also have the minicassetes that go for about 10-20 dollars. Hopefully this helps, I dont want to discourage you from building one but buying one just sounds like the way to go.

Matt

Matt

Thank you for the response. You are probably right. Can you provide a source? Also, it occurs to me that the electronics package might be suitable for me to build into the physical format that I have in mind. How about a link to some suppliers of the digital devices you mention in the under $100 range. Thanks again.

Lonnie

A few years ago, I had a palm pilot, and that had an optional cover that had a built in recorder, it was exactly what you described. I would record up to 8 min. of sound, was so small it was the cover to my PDA, and if I turned it on, no one knew but me. I used it to take notes on the shop floor rather then pen and paper.

Hey Lonnie

I was actually going to give you the link. But then I remembered that CR4 is very diverse and people here are from around the world. If you live in the USA I would suggest a site like Circuit City. In any case, if you go onto a search engine you can find some that might be cheaper, though you have to watch out for some sites.

Matt

Really, just buy one. Unless you are developing a product that you can market a bizzillian of just buy it. Do what you do best and let Japan and China do what they do best (mass produce). Chances are for the time you would spend to do the project, at even a moderate fee rate, you could buy several with bells, whistles and a remote control and still have hours left over to do whatever it is that you do best. I have a Sony BM series with the Dragon speech recognition software and it has lots of extra stuff I will never use but to even do the basics of what it does would take me, by myself, years to do and it would not work as well. If it already exists, buy it. There is seldom just cause to "do it yourself" unless you just want a hobby.

Such a device already exist, and it's called a modern cellphone.

I use mine as a Dictaphone all the time to record memoes, meetings, and phone-conversations. it can record upto 3000 hours of mono speech-type audio as *.amr format, later to be edited and/or converted to *.wav or *.mp3 on my desktop, from it's slip-in 2 Gb flash memory card.

Even a "cheapo" model (Sony Ericsson J300i for about 60 $) has only 12 Mb Flash with "only" 8 hours of *.amr recording time.

My Sony ICD-P320 Recorder stores up to 32h 10m of recorded voice (LP mode), is easy-to-use, and weighs only a few ounces, and talks to my computer (they have lengthy discussions about cosmology way into the wee hours of the morning) over a USB cable. In spite of the fact that I despise Sony's heavy-handed tactics (rootkits anyone?), this little product had the best price/performance ratio in its price range. Here's more, if you'd like to read up on it: http://www.amazon.com/Sony-ICDP320-Digital-Recorder-conectivity/dp/B000EALQ3Q#moreAboutThisProduct . (btw, GlobalSpec/CR4, your editor doesn't work well under MacIntosh Safari, but under Mozilla on Linux and (ugh) WinDoze, it works great.) -e

I must admit that I agree with everything that has been posted so far and building something like this would be far more expensive than buying and existing system.

Having said that however for reference sake the way to go about this is to use a microcontroller. There are a myriad of models and manufacturers but it wouldn't be too difficult to find one that had everything you are talking about built in. The PICkit 2^® from Microchip is a starter package and has everything you need to build something to do what you described and you can purchase one over the net for around US$50.00. I purchase one a few months back and received it in 3 days and since I live in Australia that's pretty fast delivery.

A microcontroller would most certainly be the way to go and even if you don't end up building it you will learn a lot and have plenty of fun playing with one of these kits.

Masu writes: "I purchase one a few months back and received it in 3 days and since I live in Australia that's pretty fast delivery." ***** Jeeze, Masu, I'm going to order one - from Australia! Btw, how's your move coming along? Smoothly, I hope! -e (forgive the ugly format of this post. CR4's editor seems not to work well on MacIntosh/OS-X (Tiger) Safari. I'm writing from my girl's new Mac Mini. Gmail doesn't work as well on Safari either.)

Hi e,

Yea I was pretty amazed about the delivery time as well. I was expecting to wait for several weeks and was very surprised when in rocked up in 3 days. It's even better when you consider that I ordered 2 new cable TV boxes to replace the old analogue ones about the same time. The sales people said that if I installed them myself I could have the new boxes in 3 days otherwise it would take 4 to 6 weeks. Considering that they were going to start shutting down the analogue service in three weeks I elected to do the install myself. Well the three day local delivery took three weeks and then when the boxes arrived they sent the wrong boxes. When I rang the as told them the mistake they were very apologetic and said that they would send the correct boxes but it may take a week or so. Expecting it to take a further month I was surprised when the correct boxes arrived at 10:00 the next morning.

It really make you wonder if they were really trying in the first place doesn't it.

As for the move, not as good as hoped. I was due to fly out to Adelaide with the better half but came down sick shortly before we were due to leave. The end result is the other half is packing the house up by herself while I try and get this end ready for the arrival. The only minus with this idea is that she needs to pack up my workshop and you know how engineers hat to throw thing out. Big worry!!!

Oh well I suppose it's one way of getting rid of two decades worth of junk and I am getting out of the packing.

Thanks for the input everyone.

It looks to me like the quickest, cheapest way to do it is to splice the output from a decent broadcast quality mic into the front end of an inexpensive cell phone that uses a removeable memory chip and mount the whole thing in a little case with an on/of switch.

The most interesting and educational way to do it would be with a microcontroller kit as proposed by Masu. This really appeals to me the most I must admit.

Yuvalmate--My Nokia 5135 doesnt have any flash memory and I am not aware of any capability to use it as a recording device. Is this a common function of other cell phones?

Lonnie

Today's cellphone mikes are very probably of the Piezo type due to their required tiny size and high frequency handling.

The good news about it is that it's of the highest audio quality available, only compromised by the the audible quality of the compressed file of the given format. These are usually optimised for conversational clarity, with the smallest filesize possible. To replace studio or broadcast mikes they're not ideal, but for stenographic purposes these are more than fine.

If you want to obtain a full-range audio quality, you'd better try on of the available mp3 or mp4 flash-memory-thumb-players (some of which has a removable mem-card), which has a variable quality recording facility. P.S: These usually already have a dedicated one-press recording and stop button.

yuvalmate speculates: "Today's cellphone mikes are very probably of the Piezo type due to their required tiny size and high frequency handling."

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Most cellular phones contain electret mics. They're cheaper, have (or can have) great fidelity, and are more rugged than piezo types.

-e