Analogue Electronics – a Surprising Way to Extend Battery Life

Today we look at one of the Project Priorities Perspectives in action. This was a case where performance was the most important factor and so minimising cost or time to market was a lower priority in the this Electronics Manufacture project. In this case the PCB and electronics were Manufactured In Australia.

 

We were developing a wireless Data Logger product. We selected 802.15.4 as the wireless protocol but did not need the interoperability of ZigBee. A key issue here was Battery Life. One use of the product was as a device left in the field and collected after 1 to 6 months. The actual time interval depended on the use. Since we have the client’s permission we can share details of the project and the product with you.

 

The product is a Corrosion Protection Data Logger and the client is Borgtech. The first version is the Borgtech CPL2 and it is on the market today.

 

Some key product features made it a little tricky as an Electronics Design Project:

  • inputs must withstand lightning strike impulses. This equated to 5KV for 2 seconds according to the local standards!
  • wireless connection for both convenience and also as an OH&S safety measure
  • 6 months battery life
  • 60dB rejection of mains frequencies at 50Hz and 60Hz
  • 10MOhm input impedance
  • a good profit margin

Don’t worry if you don’t understand what all the details mean, I wanted to show how we used the process to identify the best approach rather than go further into millivolts and microwatts.

 

Technically, this project was quite a challenge. And a classic niche marketing example as well. My initial approach was to minimise the production component cost and look at ways to meet the other objectives. But it didn’t take long to realise that battery life was going to be the hardest challenge here. I was able to use digital signal processing techniques (software) to meet the mains frequency rejection but the power requirements meant we were never going to get 6 months battery life and the radio side also contributed to that problem. I’ll concentrate on the filtering problem.

Analogue Electronics to the rescue

Normally we have been removing electronics components and replacing them with software to save on product cost. But this time, the priority was performance and not cost. So I added components instead. Below is a schematic representing the front end of the product.

schematic

Analogue Electronics Schematic

For those interested, this is a twin T filter. It is a notch filter that takes out specific frequencies. If you want more details then post a comment and I’ll add them.

 

The great thing about this is that it doesn’t use any Battery Power. Unlike the software solution which uses the whole power budget on its own. So from the batteries perspective, it is FREE! It did cost some design effort and did add some production cost but the battery got off lightly.

 

So here is how the priorities played out for this project. To get the performance, it cost a bit more and took a bit longer. The outcome was the right product at an acceptable price point and in a market with growing demand. Powerful stuff.

 

Now we did have to do a lot of other stuff to deliver this product so that it met every one of the design objectives. It also delivered on the client’s expectations and met the cost target too. It helped a lot that Borgtech understood their market and were able to guide us when making the decisions about priorities.

 

In practice, we make decision like the one above every day. Going left at the right time when everyone else is going right can deliver outstanding results. Marc Dussault refers to this as antimimeticisomorphism.

 

Next I want to look at going the opposite way to the path we took for this project. This is a case where cost is king and performance must be good enough but is not the primary priority.

 

Ray Keefe has been developing high quality and market leading electronics products in Australia for nearly 30 years. For more information go to his LinkedIn profile. This post is Copyright © Successful Endeavours Pty Ltd.

Project Priorities Perspective – Time and Performance versus Cost

This continues our review of the Project Priorities Perspective. See the Project Priorities Perspective post for the concept behind this.

 

This is the easiest of the the trade offs to appreciate. If you want it quickly and it has to be good, then you are going to pay more for it. This doesn’t mean you shouldn’t shop around for the best price you can get, it just means that all things being equal, the cost for this trade off will tend to be higher.

 

There are several ways this pans out:

  • you can buy in technology or expertise to save time or improve performance
  • you can use less tooling or automation to decrease the time to market
  • you can hire more experienced or qualified staff
  • you can use a more expensive technology
  • you can partner with another business to spread the workload

There is overlap between these possibilities and several may be required to achieve what you are aiming for.

 

Here is the visual representation for this scenario:

projectpriorityperspectivelogofb

Project Priorities Perspective

Now cost is a complicated trade off because there are many contributors to cost and their impact is felt in different phases of the project. For instance:

  • buying in technologies tends to happen up front and is an early cost contributor
  • creation and tooling costs are amortised over the production and so dissipate slowly
  • staffing costs also happen up front
  • production unit costs can be reduced by tooling and automation
  • reducing tooling and automation increases rework
  • tooling and automation cost up front and increase time to the first production unit
  • short cutting development effort can increase production and warranty costs
  • component costs can be reduced with creation or tooling costs
  • warranty and maintenance costs happen after production
  • maintenance costs can continue on past the selling life of the product
  • more expensive technologies can be better proven and so quicker to implement
  • more expensive technologies can provide better performance in the same development timeframe
  • another business can reduce your time to market but you will share some of the profit with them
  • being late to market can eliminate the profit all together, the ultimate cost

And estimating costs can be difficult. Particularly downstream costs like market entry delay and ongoing maintenance and support costs. See our recent post on Strategies To Be More Profitable for a more detailed look at the contributors to the Total Cost Of Ownership of a product.

 

But in general, selecting the right technology, the right team and the right supply chain will give you the greatest likelihood of getting to where you want to be, when you need to be there.

 

So who are you going to partner with to ensure your next product comes to market on time and on specification?

 

Next up we will look at getting to market faster while reducing cost.

 

Ray Keefe has been developing high quality and market leading electronics products in Australia for nearly 30 years. For more information go to his LinkedIn profile. This post is Copyright © Successful Endeavours Pty Ltd.

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