Longer battery life and cheaper solar for Bird Monitors coming

The intention of this article is to give you a little bit of insight into what's coming up for the Bird Monitor and into our development process.

Currently the Bird Monitor will run on mains power, solar, or it will last about a week on it's own battery. We have tried using a power bank to extend the life of the bird monitor on a battery. A power bank is just a bigger battery and people commonly use them to charge their phones when they are travelling. Unfortunately, modern power banks have a feature where they turn themselves off when the attached phone is fully charged. You can typically start charging again by unplugging the phone and plugging it in again. This means that when we put a power pack into our Bird Monitor, once the phone hits 100% charge the power bank turns off and we get no benefit.

The solution to this dilemma was to find some way to electronically unplug and plug in the Bird Monitor. Enter Ewen Fraser. Ewen is an experienced Christchurch electronics engineer who heard about the Cacophony Project and expressed an interest in helping. We gave him this problem and after a couple of iterations he came up with an elegant design that draws very little current (~1.2uA), is low cost, small, and most importantly, does the job. This tiny circuit disconnects and reconnects the Bird Monitor once per day (it's actually configurable) and tops the phone up. This should mean that from a 20Ah power bank the bird monitor should last for almost 3 months.

Ewen thought we should call this a Cacophenabler. I think this is a cool name but also a good example of why you don't let engineers name things. We're trying use pronounceable names after Katheryn Ryan wouldn't attempt to say Cacophonometer. Given that, as an engineer myself I'm not in a good position to come up with an alternative. Any suggestions?

The other benefit we expect to get from this device is the ability to use smaller and therefor cheaper solar panels. The solar panels need to be able to work in low light, through the winter months. Having 3 months of battery capacity could get us through the winter months, even if the solar panels produced nothing. Ewen is now experimenting with smaller solar panels.

So, to be clear none of this is available now, but it is an indication of what is coming. It's also a great example of the open source project attracting competent people who donate their time. Thank you Ewen. If you are interested in contributing or know someone then check out how you can help with the Cacophony Project


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