Thursday, August 22, 2013

Larry's Hall Effect Project

Tuesday my friend, Larry - KB7KMO, came by for a visit and work in my shop.

Larry has been sailing around the world in his sailboat for that last few years. He returns to the Seattle area to see his grand kids and families. We try to get together at least once, each time he is in town.

For this visit, Larry had several projects that we worked on in the shop. He was in need of a way to monitor the output of his generator and/or other power sources that replenish his battery banks.

The Artwork and Toner Transfer
Ready to Etch
There are may commercial products that would work, but Larry wanted to try a custom solution. For this he has found several DIY projects that suggested Hall Effect devices to monitor current.

What was needed was a small DIY PCB to hold the Hall Effect device and the few other devices that provide the input for a monitor and display.

This PCB will be mounted on-or-near the power source. The Hall Effect device that Larry will be using is shown setting on the right edge of the PCB.

My previously used and blogged Toner Transfer PCB method was used to build the necessary remote boards. We used Inkscape to create the original artwork.

Larry Cutting the Reverse Side
Toner Transfer Image
Etching is simple; put the PCB in a ZipLoc Freezer Bag, with a small amount of Ferric Chloride, and then knead while under running hot water. For a 1 oz copper clad, the process takes about 4 minutes.

Larry at the Sink, kneading the bag while running Hot water
over it, which is filled with Etch and His board
The Cut boards,
Ready for Drilling
The Hall Effect device can handle a lot of current (+100 Amps) and therefore large pads were necessary. Additional copper strap will be used to increase the current handling abilities.

This is the first time I have tried making Toner Transfer PCB with large pads or Ground planes,  on my projects I normally avoid them by using cross hatch grid for the Ground Planes. Space for some small capacitors are also included for line conditioners at the remote.

Board Inspection
Larry will finish this project, when he returns to his boat, . . . somewhere on some distant, exotic tropical island paradise !