Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Camera tilt solenoid

Fri Jan 27, 2017 6:24 pm

Hi all,

I'm trying to design a mast-top camera based on the Waveshare RPi IR-Cut Camera (minus the IR LED modules). This obviously needs to go inside a waterproof enclosure, and I would like to be able to change the tilt angle remotely. It's fine if this is just between two positions, e;g. 50 degrees downward tilt and 10 degrees downward tilt - size and simplicity are more important considerations. Thus I am thinking a solenoid actuated platform might be a good option, since this could be made much smaller than the commonly used servo driven ones, and would only need a single pin to operate. But I'm struggling to find any examples of this, or suitable hardware - does anyone here have any helpful pointers perhaps? Maybe time to get a 3D printer?

RareHare
Posts: 88
Joined: Thu Jun 20, 2013 7:17 pm

Re: Camera tilt solenoid

Sat Feb 04, 2017 8:31 pm

Do you really only want two angles-of-view, or did you actually want more, but chose two angles because you would have been happy with that?
Last edited by RareHare on Fri Feb 10, 2017 5:54 pm, edited 1 time in total.

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Mon Feb 06, 2017 4:07 pm

RareHare wrote:Do you really only want two angles-of-view, or did you actually want more, but chose two angles because you would have been happy with that?
Many thanks for your reply! I only really want two angles; I've done some testing in Blender - a brilliant tool for this kind of thing since it allows you to model the camera FOV very accurately - this is how I reached the 50 and 10 degree values. A 50 degree "down" and a 10 degree "forward" tilt angle will cover the area I want to monitor with a bit of overlap; tilting further down would not show anything of interest, and tilting further up would just show more sky... That said, the primary concern is not the precise angles, but size; I want to keep the enclosure as small as possible.
Last edited by Lomax on Fri Feb 10, 2017 1:01 am, edited 2 times in total.

PiGraham
Posts: 3577
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Camera tilt solenoid

Mon Feb 06, 2017 4:25 pm

Lomax wrote:Thus I am thinking a solenoid actuated platform might be a good option, since this could be made much smaller than the commonly used servo driven ones, and would only need a single pin to operate.
I'm sure you could do this with a single 9g servo, which is tiny and also requires only one pin to control and it can be driven directly from any GPIO pin, which you can't do with a solenoid.

Image

It will most likely take significantly less current to operate than a solenoid.
Even if you do only need two tilt angles you will be able to set what those two angles are with software.

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Mon Feb 06, 2017 5:00 pm

PiGraham wrote:I'm sure you could do this with a single 9g servo, which is tiny and also requires only one pin to control and it can be driven directly from any GPIO pin, which you can't do with a solenoid.
Golly, that's a tiny servo! Thanks for the tip! That said, a solenoid could be even smaller still :) I don't mind the electrical complications of driving a solenoid, that bit is super simple, what I'm struggling with is the mechanical aspects - both when it comes to the tilting platform, and the enclosure.

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Mon Feb 06, 2017 5:09 pm

One thing that is quite appealing with using servo(s) is that it might be possible to build a camera which can rotate around the Z axis as well, allowing me too look "backwards" (or "aftwards" as it were) as well. The current plan is to have two cameras up the mast to achieve this; a single one which can cover all angles would of course be much simpler (and cheaper!). I have no idea how I would mount such a beast to the mast though.

PiGraham
Posts: 3577
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Camera tilt solenoid

Mon Feb 06, 2017 5:38 pm

Lomax wrote:
PiGraham wrote:I'm sure you could do this with a single 9g servo, which is tiny and also requires only one pin to control and it can be driven directly from any GPIO pin, which you can't do with a solenoid.
Golly, that's a tiny servo! Thanks for the tip! That said, a solenoid could be even smaller still :) I don't mind the electrical complications of driving a solenoid, that bit is super simple, what I'm struggling with is the mechanical aspects - both when it comes to the tilting platform, and the enclosure.

It could be mechanically simple. Just a pivot one end and a wire push-rod the other.
Another benefit of servos is you can get smoother motion, less shock to the camera and chassis.

If you are thinking of pan and tilt something like this might suit:

Image

https://shop.pimoroni.com/products/adaf ... 7QodWn8BeA

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Mon Feb 06, 2017 6:07 pm

PiGraham wrote:It could be mechanically simple. Just a pivot one end and a wire push-rod the other.
Another benefit of servos is you can get smoother motion, less shock to the camera and chassis.

If you are thinking of pan and tilt something like this might suit:
Thanks, that's very cool - but also yuuuge! There's no way I could put something that big up there; not only would it look ridiculous, it would also be a massive wind-catcher. Also: it would be not be possible to get a 360 view since the mast will be blocking the line of sight for a considerable portion of the circle...

I'm looking for a low-profile, inconspicuous, streamlined solution, and I still think two independent cameras with tilt solenoids is the way to go. Smooth, shock free motion is not a requirement. If anyone knows of a suitable platform for this, or any similar builds, I would love to hear about it!

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Mon Feb 06, 2017 6:40 pm

I have just ordered one of the Waveshare "RPi IR-Cut" cameras, and will try to cobble something together. Will be interesting just to see how it performs in day/night conditions, and easier to come up with design for the housing and tilt platform with the actual device to hand.

User avatar
Gavinmc42
Posts: 3633
Joined: Wed Aug 28, 2013 3:31 am

Re: Camera tilt solenoid

Tue Feb 07, 2017 1:13 am

You could use brushless camera gimbal motors.
This one is ugly but has the smallest brushless motors.
https://www.rcgroups.com/forums/showthr ... ess-gimbal

You could use the motors from CDrom drives.
These usually have plastic ferrite magnets but these wont rust/corrode like super magnets do.
So instead of just two tilt positions you could have a stabilized camera.
Roll and pitch compensation.
To keep the weight low, put the motors at the bottom of the mast and use cable/string drive.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

PiGraham
Posts: 3577
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Camera tilt solenoid

Tue Feb 07, 2017 8:33 am

Lomax wrote:
PiGraham wrote:It could be mechanically simple. Just a pivot one end and a wire push-rod the other.
Another benefit of servos is you can get smoother motion, less shock to the camera and chassis.

If you are thinking of pan and tilt something like this might suit:
Thanks, that's very cool - but also yuuuge! There's no way I could put something that big up there; not only would it look ridiculous, it would also be a massive wind-catcher. Also: it would be not be possible to get a 360 view since the mast will be blocking the line of sight for a considerable portion of the circle...

I'm looking for a low-profile, inconspicuous, streamlined solution, and I still think two independent cameras with tilt solenoids is the way to go. Smooth, shock free motion is not a requirement. If anyone knows of a suitable platform for this, or any similar builds, I would love to hear about it!
"Huge" is highly relative. I suspect you have misjudged the size. The whole thing stands 67mm high, not much more that the height of two of those "tiny" servos that it's built around. If you only need tilt you could just use the top platform which is hardly bigger than the servo it sits on and that gives you a simple mechanical solution in a minimal size.

As for streamlined, you could house it in a short length of transparent Perspex pipe, a clear plastic food container or perhaps a wood and overhead transparency construction.

Base: 37mm x 33mm x 3mm / 1.5" x 1.3" x 0.1"
Mounting Hole Distances: 30mm x 26mm / 1.2" x 1"
Standing Height (zero tilt): 67mm / 2.6"
Top Platform: 38mm x 36mm / 1.5"x 1.4"
Weight: 37g

https://www.adafruit.com/product/1967

Anyway, these small mechanisms might give you some ideas for your own design. Using the servo shaft as the pivot bearing keeps things simple and compact.

If you wanted something ready built with streamlined enclosure you might be able to use a "dome camera" housing, but they will probably be much too large for you. Still, they might be worth a look as some have pan-tilt built in, either manual or motorised, and some are designed for pole mounting.

Another thought for keeping the camera head small would be to move the tilt platform with a bowden cable (a cable in a tube, like a bike brake cable. Then the relatively big actuator could be hidden and just a thin cable runs up the mast. Look at radio control model sites for that sort of thing. It can be very small and lightweight.

Anyway, good luck with the project. I'd be interested to see pictures of whatever you come up with.
Last edited by PiGraham on Tue Feb 07, 2017 9:35 am, edited 1 time in total.

User avatar
Gavinmc42
Posts: 3633
Joined: Wed Aug 28, 2013 3:31 am

Re: Camera tilt solenoid

Tue Feb 07, 2017 9:04 am

To keep it really small use this camera.
https://www.adafruit.com/products/1937

Cable drive inside a hollow mast.
Model airplane bowden cables, you can get plastic inside plastic versions
http://www.rcworld.co.uk/acatalog/Bowde ... nakes.html.
Low friction is the two cable pull/pull method.
But those tiny servos are really tiny, 2grams.
https://hobbyking.com/en_us/hk-282a-sin ... 08sec.html

Try to avoid any metal bits unless they are stainless or brass/bronze.
Salt air will corrode most metals.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Tue Feb 07, 2017 5:07 pm

Thanks guys, some really great tips there! I have been thinking about the tiny "spy camera", but I know nothing about its optical properties, other than the resolution (which is high enough). One of the benefits of the Waveshare IR-Cut camera is that it takes standard M12 lenses - in fact I've already ordered a decent 1.8mm f/2.5 replacement (with no IR filter). I'm also excited about the IR capability of this camera - I'm hoping you'd be able to see warm objects at quite some distance at night, and by "objects" I mean things like (big) ships, and maybe even people in the water (man overboard!). I just need to make sure that whatever "glass" I put in front of the lens is completely transparent to IR...

As for the tilt mechanism, I'm slightly warming to @PiGraham's suggestion to use a servo - I found this tiny servo from E-flite, which at just 17.5 x 6.4 x 21.8mm fits quite well alongside the camera module. I've placed the components into a quick Blend and animated the tilt angle of the camera module:

Image

By placing the servo horizontally above the camera module the footprint is kept to a minimum, and it will all fit within a 4cm wide by 5cm deep by 6cm tall footprint - just about small enough for my needs! I'm struggling a bit to figure out how to link it to the tilting platform (link arm omitted from the animation), though Blender is a great help for visualising the mechanics. Suggestions very welcome! The PCB visible behind the camera module is a Petit Studio HDMI Adapter, which allows you to use standard (shielded) HDMI cables between the Pi and the camera (note that this does not convert the camera signal to HDMI - it merely allows you to use a HDMI cable for the connection) - the adapters also provide connection for an additional four pin signals, which will be useful for controlling and powering the servo. The adapter board is fixed; only the camera tilts - this is so that the HDMI connection can be waterproofed (read: siliconed in place). The flex cable connecting the two boards should provide enough, well, "flex".

Let me know what you guys think!
Last edited by Lomax on Tue Feb 07, 2017 8:56 pm, edited 1 time in total.

PiGraham
Posts: 3577
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Camera tilt solenoid

Tue Feb 07, 2017 5:20 pm

Lomax wrote:I'm also excited about the IR capability of this camera - I'm hoping you'd be able to see warm objects at quite some distance at night, and by "objects" I mean things like (big) ships, and maybe even people in the water (man overboard!). I just need to make sure that whatever "glass" I put in front of the lens is completely transparent to IR...
Sorry but that won't be possible. The NOIR camera is not a thermal camera. It's just sensitive to near IR wavelengths a bit past visible deep red. It will see "black bodies" if they are hot enough, but that's around 200 °C (e.g. a soldering iron).
People and vehicles won't show as glowing objects. Typically you use the camera with IR illuminators to light up a scene with light that the human eye can't see (although looking directly at IR LEDs you will see a faint glow), and that's as limited in range as any other light source.

PiGraham
Posts: 3577
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Camera tilt solenoid

Tue Feb 07, 2017 5:23 pm

Lomax wrote: I'm struggling a bit to figure out how to link it to the tilting platform (link arm omitted from the animation), though Blender is a great help for visualising the mechanics. Suggestions very welcome!
Following the principle of the pan-tilt kit, you could mount the servo by it's horn and attach the camera board to the servo body. That gives you motorised hinged platform.

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Tue Feb 07, 2017 6:34 pm

PiGraham wrote:Sorry but that won't be possible. The NOIR camera is not a thermal camera.
Doh! I actually knew all that - not sure what I was thinking... :)
PiGraham wrote:Following the principle of the pan-tilt kit, you could mount the servo by it's horn and attach the camera board to the servo body. That gives you motorised hinged platform.
Interesting idea, I'll explore this option in Blender! One problem I immediately see though, is that this configuration would add considerably to the enclosure depth - the most critical dimension imo. I'm wondering if a curved piece of acrylic/plexi-glass in front of the lens will introduce optical distortions:
waveshare-rpi-ir-cut-camera-tilt-housing_02.jpg
waveshare-rpi-ir-cut-camera-tilt-housing_02.jpg (30.43 KiB) Viewed 3212 times
waveshare-rpi-ir-cut-camera-tilt-housing_01.jpg
waveshare-rpi-ir-cut-camera-tilt-housing_01.jpg (28.56 KiB) Viewed 3212 times
This enclosure has a 39mm wide, 42mm deep and 48mm high footprint.

RareHare
Posts: 88
Joined: Thu Jun 20, 2013 7:17 pm

Re: Camera tilt solenoid

Fri Feb 10, 2017 5:56 pm

What type of cable are you planning to use between the computer and the camera?

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Sat Feb 11, 2017 7:53 pm

RareHare wrote:What type of cable are you planning to use between the computer and the camera?
At the moment I'm using the HDMI adapters from Petit Studios, which work very well indeed with a 2M cheapo HDMI cable I had lying around. I've seen reports that even a 5M cable works without issues, which is more than I need. I am however interested to know if anyone makes an FPC DIP15 breakout board for soldered connections instead, since it's going to be difficult to waterproof the HDMI connector entry. This would also give me more freedom wrt the positioning of the FPC adapter board; since the HDMI connector must point downwards I am forced to put it behind the camera board, which adds ~10mm depth to the enclosure - I would rather place it below or above, since enclosure height is a much less critical dimension. This is what the internal layout looks like now:

camera_layout.jpg
camera_layout.jpg (30.88 KiB) Viewed 2781 times

Lomax
Posts: 188
Joined: Wed May 20, 2015 9:43 pm

Re: Camera tilt solenoid

Sun Feb 12, 2017 5:12 am

Couple of renders of how the housing will look. Final dimensions are 46mm W x 55mm D X 54mm H. The mechanism should allow for 0 to 60 degrees of tilt. Housing made from laser cut 3mm white acrylic, window from cast 1mm clear acrylic. Anyone know of a good (and cheap) laser cutting facility in the UK?
Attachments
housing_60_degrees_tilt.jpg
housing_60_degrees_tilt.jpg (19.97 KiB) Viewed 2718 times
housing_0_degrees_tilt.jpg
housing_0_degrees_tilt.jpg (19.86 KiB) Viewed 2718 times

User avatar
Gavinmc42
Posts: 3633
Joined: Wed Aug 28, 2013 3:31 am

Re: Camera tilt solenoid

Sun Feb 12, 2017 6:18 am

Anyone know of a good (and cheap) laser cutting facility in the UK?
Seem to remember Pimoroni started the Pi laser cutting industry.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

PiGraham
Posts: 3577
Joined: Fri Jun 07, 2013 12:37 pm
Location: Waterlooville

Re: Camera tilt solenoid

Sun Feb 12, 2017 10:57 am

Lomax wrote:Couple of renders of how the housing will look. Final dimensions are 46mm W x 55mm D X 54mm H. The mechanism should allow for 0 to 60 degrees of tilt. Housing made from laser cut 3mm white acrylic, window from cast 1mm clear acrylic. Anyone know of a good (and cheap) laser cutting facility in the UK?
You could try contacting your local makerspace.
There are bureau companies that do that. You could also try plastic supply companies and companies that sell acrylic signs.

Return to “Camera board”