Wednesday, 28 January 2009

FieldCam - A Solar Powered 3G Wireless Webcam!

Of course, the first thing to do when you buy a field is to set up a webcam in it so you can see what's going on - well, maybe that's not the norm, but it seemed like a fun project and a great way to bring the field "alive" for the family. The final plan is to have a digital frame on the wall in the kitchen, which updates with the latest picture from the field, but first we have to get some pictures somehow.

So, where to begin. The field has no power, and obviously no internet...

Power can be solved to a degree with batteries and solar panels, and I've done some playing around with those before so it seems an obvious place to start. For size and cost reasons I picked up a 12Ah battery from Maplin (about £30), and a 15W panel (and 5A charge controller) from ebay (about £70). I found some figures to suggest that a 15W panel should provide 6Ah of power on a sunny day, so that seemed to fit well with the battery at least. Of course, bigger would definitely prove to be better in both cases, but these should do for now.

One of the decisions I made early on was to conserve power and bandwidth by turning the whole system on every so often, taking a photo, sending it, then powering down. I had a breakthrough here when I discovered the REUK site, a great resource for bits for renewable energy projects.
The guy who runs the site, Neil, also builds custom circuits and very quickly created a module for me which would power-up every hour, check that the voltage of the battery was 12v or above and if so, flip a relay to provide power to the rest of the system. After 15 minutes the relay opens again, and the system powers- down. If the voltage is less than 12v then we just skip that cycle, and give the battery another hour to build up charge. 15 minutes was chosen for reasons that made sense at the time, but actually is far longer than the system needs to be on. I've since asked Neil to re-program the chip on the board to only stay on for 5 minutes - which should give me more photos per day before the battery goes flat.

Internet access is provided by a 3G USB modem - on a Pay-as-you-go plan from 3, for just £10 a month.  I did some tests using a laptop in the field (field tests?!) and found that 3 gave me much better results than O2, which barely worked, and I also liked the lack of commitment in a PAYG plan - so 3 it is.

The USB modem is plugged into a clever little router that 3 sell for about £70 - the Huawei D100 - this can be configured to auto-dial the internet through the USB modem. It also has a network port and a WiFi network built-in.

There was a little wrinkle in that the D100 has a soft-switch, which needs to be pressed after the unit is powered before it will turn on. That foxed me for a while, but then I opened the unit up and soldered some flying leads around the soft-switch. Quickly shorting those together did the same job as pressing the switch (obviously I guess, but I needed to check). Now all I needed to do was automate this shorting process after power is applied to the D100. A quick email to Neil at REUK, resulted in a solution in the post the next day. This module waits 2 seconds after it is powered up, then closes a relay for 0.5 second then goes to sleep, with the relay open. I wired this into the D100 supply and the flying leads around the switch, and sure enough - my modified D100 automatically goes online after it gets powered up without me needing to press the "soft" power button. My rough measurements suggest that the D100 draws about 200mA when its up and running - with 3G and WiFi turned on. That seems good to me.

The final part of the solution is the camera, which needs to be outdoor-proof, IP capable, and be able to schedule a send of a photo preferably by email.
I chose the Y-Cam Black and its weatherproof shell, for about £150 all told. This is one bit of the solution that I think might be over-specified - the Y-Cam Black has night vision, which might be cool so we can see the field at night. And it has WiFi, which I first thought I needed but actually don't use, preferring a wired network connection straight into the router. The biggest issue I have with the Y-Cam  (aside from its bulky ugliness) is its current use, which I measured at about 300mA - and that is with WiFi off and in the day time, so the night vision LEDs are turned off. On the upside, it turns on and finds a network without any fuss, and can be scheduled to take and send a photo to an email address, so it does the job. I will look out for another cheaper and hopefully less hungry camera for this project though, as I can always make use the Y-Cam at home.

So, to recap - the FieldCam has a battery which is topped up by a solar panel. Every hour it powers up, checks the battery level and if that is ok (over 12v), flips a relay to provide power to a mobile internet router and a camera. The camera in turn is set to take a photo and send it to an email address (through the router) some time later. Then it all switches off and hopefully charges up a bit and the cycle starts again.

The final part of the assembly was a big waterproof box to put it in, which again came from ebay - I think its real job is to keep extension leads dry when you plug your Christmas lights in - but it was the right size and a reasonable price.

Here's all the kit in the box - ready for deployment. The battery is easy to spot, then the two blue relays on the custom mmodules. The D100 router is underneath to the right, and the camera and solar panel are out of the box, not in shot.

The plan is to leave this gear in a field and have it send photos to me while its unattended, so I've got to worry a little bit about making it and its parts robust and secure. I did this by making a sort of wooden sledge, which has the advatange that I can carry it, but its quite big and awkward to carry very far.

The picture here shows the sled in my garden, prior to deployment. The waterproof box sits on an old decking tile, underneath the solar panel. A strut goes across the lid of the box, so a screwdriver is needed to get inside and see what's going on. Hopefully this will prove enough to discourage any casual walkers who stumbles across the set-up!


  1. I am very impressed with your design. I have a new vineyard in Walla Walla Washington, USA and would like to deploy a similar device at my location.
    Does your device continue to perform as intended? Have you found any similar commercial solutions?

  2. Hi,

    Thanks for the kind words - its all still working surprisingly well!

    Now the weather here is getting greyer I'm seeing the battery run out earlier in the day and the photos stop coming, but then it starts up again the next day as soon as it charges up again. We haven't seen a lot of wildlife, but have seen some spectacular sunsets, and the odd rabbit and hare. Its also been wonderful to have the field pictures in the kitchen, and makes sure we don't forget we own it!


  3. Hi Iain, loving the project. Is there any chance you can upload a wiring diagram?



  4. Hi Iain, This is indeed outstanding. You have turned around a pain point and created a very elegant solution.
    I am writing from India and I plan to engage in agriculture activities in a remote village in India (obviously with no electricity or communication).. As a first step, I would like to capture these images and have them saved to a disc as opposed to transmitting them and yes all of which needs to be solar powered. I am really not tech saavy and I am hoping you could provide some pointers on how to do that. I might need to save images for 30 days at a time..

  5. I am considering a similar system for monitoring a Peregrine falcon nest on a cliff and need to put the system on a calendar/clock as I only need it to work for a brief period a couple of times per week from April - July. Any thoughts on what kind of circuit one could use for that?

  6. Hi,

    Been a bit behind on replies - sorry!

    @simon: don't really have a wiring diagram, sorry

    @Anand: you can probably find a camera that will save to SD card or similar? Something from the security industry maybe?

    @JHealy: Sounds like a great project - you could probably do something similar to my design, the key is to not have the camera on when you don't need it taking photos, hence my "master timer" which powers the camera up and down. You could also try one of the new MiFi access points, they may use less current than the box I use, so would need smaller battery and panel.


  7. Hi (@anand), you could also build the solution around a pico motherboard.

  8. Hi Iain,

    I work for Y-cam Solutions, and I just wanted to say. Wow! Thank you for using our cameras and in such a wonderful way. I've been looking through your photo stream and there are some great shoots :). I would love to talk to you about your application so if you would like to please contact me at victoria (at), be great to hear from you.



  9. Kudos to all the developers! You did a great job!
    mesa security systems

  10. Greetings Lain,
    Read your system with great interest as we have a farm that has remote livestock waterers that occasionally freeze in winter and would benefit from this kind of monitoring. Is your system still satisfactory for you? Have you considered a commercial application for people with little time and low tech skills, such as myself, who would be interested in a turn key version.
    Sincerely impressed, Philip

  11. I am looking for this exact solution for my field. Would you be willing to build me a unit? And we buy it direct from you including the extra cost of your tune and energy?

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  13. FieldCam - A Solar Powered 3G Wireless Webcam! ...

  14. what is this module " module waits 2 seconds after it is powered up, then closes a relay for 0.5 second then goes to sleep"