Drionic Modifications:
Say No to Batteries!
February 19, 2001
Last Update: January 21, 2003
by Carolyn Lamoureux

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Drionic uses a proprietary 9-volt dry cell battery ("LG" cell) which resembles a J-type battery used in many pagers, but J-cells are 6-volts and are about two-thirds the size. The LG cells are not available for purchase anywhere except from the manufacturer of Drionic, General Medical Co. They are pricy in the long-run ($7.00 for a pair, with a minimum $12.00 purchase plus $5.00 shipping in the U.S.) and have a finite lifespan (the manufacturer estimates about 6-7 hours). Some Drionic users have modified their units to use standard alkaline 9-volt batteries which are readily available, but there is still the need to replace them from time to time.

For the cost of replacement batteries (and a little bit of time to do the one-time modification), I have adapted my Drionic units to use power supplied from a pair of 9 VDC, 300-500 mA AC-to-DC transformers. The modification does not render the "LG" batteries unusable, so you can still use batteries (e.g., for when you travel), or "over-ride" them when the transformers are plugged in.

Tools and Parts List

The modification required the purchase of the following:

  • 2x 9VDC DC wall transformers (center negative)
  • 2x 2.1mm DC power jacks (switched) - has 3 poles
  • wire (about 1 ft total), 20-24 guage
  • solder, soldering iron, wire cutters/strippers

    The first two items can be purchased at most electronics/hobbyist stores. For the transformer, buy the lowest current rating you can find (typically about 300 mA) as these are typically lower-priced. The available current doesn't really matter (the Drionic device only draws about 20-30 mA, so anything over is simply not consumed). I personally used 500 mA transformers because I couldn't find anything lower at the time. I purchased them from a company in Calgary, Canada, called MRO Electronics: the transformers were CA$7.20/ea, or ~US$4.80/ea (PN 68-950-1), and the jacks were $1.15/ea, or ~US$0.77/ea (PN 31-134-1).
    [02/05/02: Due to popular request, I've identified comparable parts from Radio Shack, although I haven't actually gone out and bought the stuff, so keep in mind this is my best guess. For the transformers you can try RS#273-1767 (US$9.99/ea), and for the switched jack, try RS#910-0902 (US$1.79/ea). Wire is very generic, but since I've been asked: try RS#278-1222 (US$4.49 for 3 spools), which will give you way more wire than you'll need for this project.]
    [01/21/03: I've received numerous e-mails from people indicating that Radio Shack no longer carries the switched 2.1mm power jack, and wondering where a substitute item could be found. Again, I have not ordered the components myself, so I am just going by the available online data, but you can mail-order all sorts of stuff from Digi-Key (www.digi-key.ca in Canada, or www.digi-key.com for U.S.) or Jameco Electronics (www.jameco.com)... for the 2.1mm DC jack, try DK P/N CP-5-ND or JE P/N 151589. A substitute for the 9VDC transformer is JE P/N 134025 or 170270.]


  • 1. A hole for mounting the jack (in my case, 1/2" diam.) has been drilled into both Drionic devices as shown. I didn't have a 1/2" drill bit, so I drilled a smaller hole and widened it using a Dremel tool.

    2. This is a view of the holes when the Drionic units are turned upside-down with the cover removed.

    3. The 2.1 mm DC power jack is now mounted, with bottom view of one unit, and front view of the other. The nut which holds the jack in place is tightened to secure it in place.

    4. It is difficult to describe the power jack in layman's terms, but if you can read a schematic diagram, this figure illustrates (A) the Drionic unit prior to modification (jack is separate), (B) the modified Drionic with the jack wired in (notice the battery can still provide current to the Drionic circuit board, and (C) the unit with the external DC adapter plugged in to provide power (cutting off and conserving battery-supplied power). Determining which of the three terminals is which on the power jack might be a bit tricky unless you have a continuity tester or multi-meter. The center post is easily identified by its central placement (and slightly larger rivet) on the wafer which the three terminals are mounted. If you have a continuity tester, simply plug the external DC adapter into the jack (without plugging adapter into a power source) and test for continuity between the terminal and the outside barrel of the adapter.

    5. Here I've identified the red wire from the battery to the circuit board, and de-soldered it at the circuit board end (taking note of where it was). I then soldered this wire to a terminal on the jack (per diagram in #4 above). If you don't have a soldering iron available, another way is to snip the red wire about halfway between the circuit board and the battery, and then stripping about 1/4" at the end of the plastic sheath. You can then splice a wire to extend the wire from the battery, and tie it to a terminal on the jack.

    6. Next, I soldered a new red wire to the circuit board (where the former red wire was) at one end, and the other end was soldered onto the other terminal of the jack. Again, you can splice a new wire onto the end of the cut wire (hanging off the circuit board) and extend it to the power jack.

    7. Finally, I soldered a new black wire between the center terminal of the jack and the negative terminal of either the battery or the circuit board (I've wired it up to the circuit board).

    8. Test your unit out: Without any adapter plugged into the Drionic device, the battery (assuming it's not dead) should provide power to the unit (green LED illuminated). When the AC/DC adapter is plugged into the Drionic unit (but NOT into an AC outlet), the green LED should go out. Once the adapter is plugged into an electrical outlet, the LED should again illuminate, indicating it is getting external power.

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