AC power adapter HHP-CM01

The DC connector on my Omron has an outside diameter of 4.00mm.

For a sample of a potential type match... these tables can help on the ID.

You can for example, make up a barrel adapter, going from an M to a B, in an effort to fit some other junk drawer adapter.

But the problem of fitting adapters, it also depends on whether the original Omron was "fully specified" so you can get all the electrical details right. Four AA might be 6V, and you would suspect the needed adapter is 6V or higher. And the plug polarity (center "+" or center "-") is correct. The black plastic on some items, has a "raised legend" indicating some important parameters. It can be hard to see, unless you know it is there.

At the (defunct) Radio Shack, they kept a "Hydra" on the wall, a thing with fifteen cables on the end, and fifteen plugs, and customers were expected to measure their kit and determine the barrel size required (like the "B" above). That's the Adaptaplug idea. In some cases, the barrels are close enough in size, you can only narrow to the closed two plugs (one of the plugs was a bit on the tight fitting side).

Maybe a lot of common electronics at home, have "M" or "N" barrels, and a "B" would be a problem when reaching into the junk drawer. it will take some "craft" to fix (build an adapter for the adapter, or solder a "B" onto an existing cable end).

Adapter types are:

Regulated DC (phone adapters, USB chargers) Unregulated DC (my label maker, can tell because wall adapter is heavy chunk of copper) AC (Just a transformer, output proportional to mains voltage swings)

Then the barrel can be center "+" or center "-". And the AC has no polarity as such.

Some replacement wall adapters have a slide switch with canonical voltage values, and 5V and 6V and 12V can be available on those (a total of six values I think).

Always be very careful about polarity! Absolutely nothing has diode protection to prevent blowing stuff up. Never assume "if I make a wiring mistake, the gadget front end is protected". Nothing is "built" for DIY bodging. They have assumed you are using their adapter, and thus, no protection is needed. It's up to the user to be careful about what they connect, from the junk drawer.

The barrels are not a voltage declaration. They did not invent all these barrels so "yellow was 5V", "green is 6V". A barrel can have anything on it, 5V or 19V. This is one of the reasons you have to be so careful when playing this game. The DIY person is the "quality assurance", absolutely nothing about the barrels is helping us get this right by some magic.

Adapter Load current Working?

On a BP handheld, the pump motor is a significant load. The motor startup transient will be the "test" of the overcurrent design of your selected wall adapter. Batteries are a lot more tolerant of this motor startup behavior. A little extra current capability on the adapter, helps ensure the pump motor runs. Some wall adapters actually lie about their spec, and can produce an extra ampere for a few seconds (because the transient load characteristic is a known thing). But for most of the charger type adapters, those would precisely cut off at the stated max current flow level.

You may also notice, when a BP device is run on an adapter, the pump motor is "a lot more spiffy". The design is centered on the battery voltage dropping while the motor runs. Whereas a regulated adapter will keep the cuff pump running at high RPM. This is not particularly a concern -- just a warning to not be alarmed about the sound you hear. It could sound different on batteries, versus an adapter.

Paul

I have plenty of power supplies here with barrel adapters that deliver 54V for POE+ switches. They fit in lots of other devices.

However, if the product can use an external power supply and is genuinely CE or UKCA marked it will have a declaration of the rated input voltage and current or power together with the polarity of the connector.

John

First hit on Google

The label on the adapter in the image says 9v 600mA DC centre +ve

and in the same image it states 6v 1A which I think is correct.

It correlates with this cheap one from AliExpess for under £5 delivered.

The socket is marked DC 6V plus an indicator that the centre pin is +ve

This is a hobbyist solution.

The selection of "barrels", may include a B. Maybe the yellow one at the bottom is the right one.

One thing you have to be careful of, is the "insertable barrels" can be keyed, or not keyed. And it is the responsibility of the hobbyist to check that they plugged it in the right way to get center (+). The advert will never tell you which kind the product uses.

o o # This adaptaplug is un-keyed. You can plug it in wrong and ruin electronics!

o O # This one is keyed, and is only intended to plug in one way # Whether this is always center (+) I don't know.

You can make up adapters, by buying female and male items with soldertail connections on the end, and that would likely only be acquired from an online electronics dealer. They might have, say, a female M and a male B, and you would wire those together to make an adapter for some wall adapter which you already own with an M barrel on the end.

The adapter also needs to have enough current capability for the load. The BP meters have a pump inside, and the motor draws a bit of current when attempting to pump up the cuff. You would check the existing adapter for current, and select the same current or a higher current (which ensures there is sufficient capability for the job).

Paul

"This Product is no longer in stock" :-(

There are similar offerings this side of the pond but all I want is the actual barrel connector that I can use with one of the many 6V DC power supplies that I have in my box of many assorted, might-be-useful-oneday electrical thingies

I managed to buy a barrel connector on a SPOW (straight piece of wire)

If you do this often it's useful to have a set like this:

If 4.0x1.7mm is indeed the right size then premade cables are available:

Only the more common sizes are available in non-moulded hand assembly versions, so you may not be able to get a solder-yourself version in this size. In this case here's one:

Theo

The closest I can get right now, is a solder-tail 4mm

But the ones above are soldertail, and you can use whatever wire you have handy that will hold up. The remaining cord on the adapter to be re-used, could be the source of wire. Needs a multimeter for polarity test, because it's very easy to switch the two wires when working with barrels.

Paul