General question: Best method for Wheelchair backup camera
micheal_wolfe wrote 01/23/2020 at 15:23 • 0 pointsI am working on a backup camera for my nephew who is wheelchair bound.
I have tried several avenues and each has drawbacks:
- Endoscope - I can't seem to find any that plugs directly into an iPhone (Android no problem, but he currently has iPhone)
- Raspberry PI TFT over GPIO - Having issues getting the image on to the TFT (using Adafruit's camera drivers)
- Raspberry PI TFT over HDMI - (on order)
- Raspberry PI with iPhone - Bluetooth has low bandwidth (but is a possibility) and WiFi requires some logistical juggling to deal with being available both on network and when mobile. (I started with Nils Pickert's project "Rear view camera for electric wheelchair", but went to a python streaming solution for less delay)
I am really just looking for ideas. I think I am too close to this. It just needs to be mobile, low(ish) power, and would be nice if it could work with the iPhone without isolating it from the local WiFi.
Thank you for any comments.
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just go with a small camera for a quadcopter and a small display. these can be purchased extremely inexpensively and are pretty durable. the focus length can be adjusted by turning the lens and they are powered from very simple batteries.
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Some of these quad racing FPV systems are very cheap and have receivers that plug into the phone with an OTG cable. The android store is full of app to view.
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ESP32Eye BLE + wifi is cheap and easy to use. This is an open source design which I have customized with success.
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I'd look at aftermarket automotive solutions. Those cameras already have a the proper lens, to get a wide angle view. Combine this with a small LCD display. Add a simple on/off switch to save power when not in use.
Keep it as simple as possible.
Maybe even a mirror is all that's needed.
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Thanks, I considered both of those solutions, it is preferred to reuse the phone as the view port. The reason is that space on the front of the chair is at a premium. The phone has multiple uses. I use the 270 degree pi cam so the view angle is not a problem.
I did purchase the car backup cam, but I am really in the same boat with the limited space at the front of the chair.
I really agree with keeping it simple, that's why I posted, but the user case is kind of driving me to the phone. I was investigating the TFT angle as an alternative for someone else as well. I that case a back up cam is a better solution.
Thanks for taking the time.
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No problem.
The downside I see with the phone solution, would be that it would take some time to start the "App" and connect to the camera. Would waiting 10-20 seconds before being able to reverse, be acceptable to your nephew?
Another idea. Some dashcams also have WiFi, and can be viewable from your phone. Same for goes for GoPro. Both aren't that power hungry. You'd have to look at how usable the apps for them are, though.
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Actually I have the app running on the WifI networks (just haven't done the work to get it to work without one) and it starts up nearly instantly from a desktop safari short cut.
Only one minor issue. Safari hangs inexplicably fetching the stream 1/2 the time. Server side app (python) reports that the browser never makes a stream element request after loading the landing page. I'm just using <img src=URL>. However, the same html works fine in Chrome on iOS, buuut Apple won't let you create desktop browser shortcuts for non-Safari browsers. So very much moving him to Android ;)
I think I am nearly finished with the Pi/Wifi/browser solution. It's overkill but gives him what he wants. Just wish I could figure out what Safari hates about that HTML so much.
I had considered the WiFi camera approach, but could not figure out how to deal with the mobile problem.
Thanks again for taking the time to talk through this. When I get a working version I will upload it all here and see if I can iterate a better solution.
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I'd try using the `video` element instead of the `img` element.
If that doesn't work add some javascript to reload the page if the "image" isn't loaded in, say, 2 seconds. Let me know if you need any help with that.
Last option is to have a separate page for the homescreen-shortcut that in turn opens the correct page in Chrome ( googlechrome://example.local/stream/). Or only use chrome for the reverse cam and Safari/Firefox for browsing, and always have the stream page open in chrome.
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