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Archive for January 30th, 2019

DSO150: USB Battery Charger

Continuing the process of silk-purse-izing the DSO150, a batch of USB 1S lithium battery charger modules arrived from halfway around the planet. I drilled & filed a suitable hole / slot / aperture in one of the few remaining spots in the case, then stuck the PCB to the bottom with good foam tape:

DSO150 - USB charger - internal layout
DSO150 – USB charger – internal layout

Because the charger includes cell protection circuitry, I replaced the original protected 18650 cell with a bare cell sporting solder tabs. The cell should go directly to the charger board, but the switch disconnects the + wire; I’m unwilling to believe the charger won’t slowly and inexorably discharge the cell if I don’t use the DSO150 for a few months. It could happen.

A label makes the hole look almost professional:

DSO150 - USB charger - Micro-B jack
DSO150 – USB charger – Micro-B jack

Well, makes it look Good Enoughâ„¢, I suppose.

The power switch gets a label, too:

DSO150 - USB charger - battery switch
DSO150 – USB charger – battery switch

Flipping the switch ON lights up the scope from the battery.

The charger (sensibly) will not route power from the USB port to the scope without a battery, so you must plug in a USB source with the switch ON, then flip the switch OFF. I don’t know why you’d want to do that, but there you go.

Now it’s a real portable instrument, with all the inconvenience of managing a built-in lithium cell.

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