Monday, April 2, 2012

Pressure & Temperature Controller

I recently used one of the leading crowd sourcing sites to find an electrical engineer to design a controller unit for a planned upgrade to the rocker table. I realised after seeing the homepage on that I am indeed a late comer to the party as the number of projects completed is a touch over 1.5 million.

The project was to design the controller and PCB for a temperature and pressure controller unit that would interface with the recent microcontroller based, standalone computer kit that I put together called the Maximite. The controller needed to be able to take input from 4 temperature sensors and 2 vac pressure sensors and be able to switch 3 independent loads of up to 1 kw each (heat lamps, vac pump + 1). The Maximite will provide the intelligence for the controller as well as being able to log the temperature and pressure data.

I posted the project on Freelancer and within a matter of 1/2 hour bids started to come in on the project. The bids varied widely in price and presentation. I eventually awarded the project to an electrical engineer in the UK - Nik Staunton. It was an interesting experience as Nik's bid was higher than most of the other bids yet when his proposal came in it took almost no time to decide to award it to him. Its a very interesting thing about how we make such decisions. In this case I was looking to hire a supplier I have never met and will never meet, who I never heard of and through a site I have never used before. Part of process was actually working out how to select someone although the search was a subconscious one.

Its interesting the cues you take in when you think your asking 'who' but actually trying to answer 'how'. Like gazing into clouds our minds are able to construct a reality based on light and dark spots in fog and so too I found myself building solid pictures of the bidders based on the oddest cues, plus I have an underlying desire to take a risk out of respect for this brand new world of procurement. Then Nik's bid came in and was at the higher end of the bids but included a professional scope of work that demonstrated an understanding of the project and a familiar level of professionalism and it was then that I realised that Freelancer is not a brave new world its just a different way of the doing the same common sense thing I would do if I was hiring someone down the road - paying to minimise risk; minimise the risk of being electrocuted, the risk of getting a dud product, the risk of my $$ disappearing into the ether.

So to the credit of my 'Ah ha' moment Nik delivered the project  ahead of schedule and with supporting documentation, bill of materials and all the files that I needed to get the boards made.

A very good first experience and one that I plan on repeating.

As for the board, I found a local manufacturer who will make the bare boards ( no components) at $130 for 2 ( most of which is set up cost) - very reasonable for prototype boards. I'm yet to price the components.

If you are looking for a bespoke electronics project I can highly recommend Nik, as I've done online ( I promise no kick backs here just wanting to share my successes with others) or via

No comments :

Post a Comment