Repurpose smartphone as oscilloscope camera.

I'm looking at making a scope camera out of a smartphone. I have an old Tek 422 and I want hack one of those bluetooth camera remotes and connect it t o the gate output of the scope. I've been looking at smartphones on ebay an d some of the cheap used ones are locked. How disabled is a locked cellphon e? I understand I can't connect to the phone network but what other functio nality is disabled? Specifically can I run the camera through bluetooth?

Thanks

Reply to
Wanderer
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There's probably already an app for some smart phones - If you can find an old Gameboy; Many years ago, Elektor magazine published a scope card project that goes in the game slot.

Reply to
Benderthe.evilrobot

"Locked" may, or may not, mean that the only supported (or permitted) way to install new applications, is to do so from the original cellular-network provider's own application store/repository. I don't think this is all that common but I'm pretty sure it occurs. Whether anything else is disabled if the phone doesn't have service, is going to depend on the phone, former cellular provider, and whatever business and contractual and technical restrictions were originally in place. Some phones might be totally unusable (completely locked out), others will be usable for everything but phone calls (and, here in the US, you'd probably still be able to use the phone to make a 911 call if there's a compatible cellular network within reach).

Whether you'll be able to control the camera via BlueTooth is a question that's very likely to be specific to the camera model, the version of the resident software, and the specific camera-control application that's installed and running.

Even if you can control it, you shouldn't count on a really rapid "shutter release" when the BlueTooth remote signal "fires". The camera may insist on doing another focus-and-exposure calibration cycle before it actually fires, and you may miss one or more trace-scans on the 'scope before the exposure takes place. This, also, is likely to be camera-model-specific.

So, I'd recommend asking the seller what functions are available, or locked out, before you bid/buy.

Reply to
Dave Platt

Instead of buying an old smartphone, buy an old iPod Touch. 4th gen was the first gen to have both front and rear cameras, Bluetooth, and WiFi.

No cellular connection so no "locking" issues to worry about.

Probably pick up a used 4th gen for around $30-50

Reply to
bitrex

Usually modern Android smartphones that aren't signed up to a provider work fully-featured with WiFi, Bluetooth, the app store, etc.

Just can't download anything over the cellular network or receive calls/dial out (other than 911.)

My girlfriend uses her previous Android phone as a workout music player now via WiFi, it works fine.

Reply to
bitrex

Doesn't that mean you have to use Apple software to read the pictures? Sod that for a game of soldiers.

I have a couple of smartphones without SIM cards, one Windows/Nokia, the other Android. The Windows one is mostly on my bike as a video recorder, and sometimes in the car as a satnav - maps are free. The Android phone takes timelapse photos of a nearby development. Both just plug in to the PC and look like disk drives, couldn't be simpler.

For phone calls, I uses a non smart phone. A battery charge lasts a couple of weeks.

Cheers

--
Clive
Reply to
Clive Arthur

Nah, they just get dumped to a folder on the device in JPG format and you can pull them off onto a PC as you would if they were on an SD card or USB stick, same as any smartphone.

The iOS software can be set so any photos taken are automatically uploaded to your Dropbox in JPG format as well.

Reply to
bitrex

I can't recall if it's the same on Apple devices, but on Android smartphones the default is that all pix taken with the camera end up in a top-level folder called "DCIM"

Reply to
bitrex

Great. That's what I hoped.

Reply to
Wanderer

Most modern smartphones have 3 or 4 connector headphone jacks because they're designed to accept headphones with volume controls / buttons on the leads.

It would probably be faster to send the trigger input in that way than over Bluetooth; I'm sure someone has written some kind of app or something to let you trigger the camera shutter from the headphone buttons...

Reply to
bitrex

I know there are a lot of issues that will need to be dealt with starting with getting -5v pulse to trigger one of these.

formatting link

Reply to
Wanderer

I mean -0.5 volts.

Reply to
Wanderer

Thanks, I didn't know that. I won an iPod touch (no camera) some years ago and was mightily pissed-off to find that I couldn't just copy .mp3 files to it, so it remained virtually unused. I assumed that applied to pictures too.

Cheers

--
Clive
Reply to
Clive Arthur

d

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Apple does many strange things to protect music playing, but not for pictur es. Anyway, you can just get cheap Androids and not to worry about the App le lock. And other said, you can just mount it as USB disk, or "adb pull" it. I prefer "adb pull" because it always work. USB disk sometimes can be disabled in settings.

Reply to
edward.ming.lee

Or buy a digital oscilloscope!

--
John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

I used my old one to watch NetFlix in the gym (recently replaced it with a 7" tablet). The cell phone before that is serving as a I-Heart-Radio in the basement.

Reply to
krw

and I want hack one of those bluetooth camera remotes and connect it to the

gate output of the scope. I've been looking at smartphones on ebay and some

of the cheap used ones are locked. How disabled is a locked cellphone?

I understand I can't connect to the phone network but what other

functionality is disabled? Specifically can I run the camera through bluetooth?

As always, what you do is critically dependent on your EXACT requirements. If you have a stable trace, just push the button on the camera and be done with it. If not, your problem just got WAY more difficult.

If you only do this occasionally, try taking a video and post processing a frame out of it.

Back in the day, I put a USB webcam into a TEK scope camera housing. I used a transistor to "push" the shutter button triggered by the sweep gate output. Results were dismal. Getting a single shot trace capture was impossible at high sweep rates. There were too many delays in the system. The shutter open time didn't correspond with the scope display visible time.

With a smartphone, there are many automagic processes going on. The phone expects a stable scene and takes its time figuring out how to get the best picture. You don't have that time for a scope trace. For example, the exposure time might be conditioned on the amount of light. The scope trace is a tiny fraction of the total screen area. Depending on the algorithm, the exposure may be WAY off. More likely, there won't be anything to see but the phosphor persistence because the trace is long gone. Bluetooth makes it worse.

Wired selfie sticks use the headphone jack as input to trigger the shutter. That's probably the least variable option you have. Load a selfie stick app and see what happens. My selfie stick was bluetooth. I played with it and found that it worked great on some phones and not at all on others. I didn't try to capture a scope trace with it. I expect the result is still horrible in the general case. In specific slow trace cases, it might do what you want. Depends on the requirements. This may not work at all on an old phone. Probably needs some recent Android version.

If you have a repetitive sweep, you'll be "pressing" the shutter button hundreds of times per capture. The phone may object to that. If you have only one trace, the phone may object to capturing what you want. YMMV.

I wouldn't spend a lot of money on smart phones for this purpose. I don't think you'll be happy with the result.

Here's an experiment you can try. Connect a LED to the gate output. Use a red or green one. The white ones have phosphor and will obscure the time. Put the LED up near the scope screen and take a video of the scope at the highest frame rate for various sweep rates and repetitions. Copy the video to your computer and look at it a frame at a time. Compare the intensity of the LED to the "goodness" of the trace. That might give you some idea of how well the gate output might be able to control the shutter. I haven't tried that, so don't know what to expect.

Are we having fun yet?

Reply to
mike

That I can do this cheap is a prerequisite. Like this phone

Samsung Intercept M910 Android Phone Virgin-Mobile STEEL GRAY keyboard WiFi

Works, $9.99, Free shipping, 5hours left, no bids. Why? What's wrong with it. These old phones are selling cheap. Not good enough for modern social media, anymore?

Reply to
Wanderer

Beware the old operating system. May not be able to run the apps you might need to do what you want. I'd stick with Android 4.4 or better. You're probably gonna need a camera with closeup focus capability too.

Reply to
mike

On, you CAN copy '.mp3' files; the music player, though, has indexes by album, artist, genre, 'stars', etc., and you only get the benefit of those lookups if you put the '.mp3' into iTunes and let it fill the database. The 'play music' menus only look at the files through that database index.

Heck, I've put bootable OS onto an iPod. It's an external disk.

Reply to
whit3rd

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