PINNED - Cushions

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Re: PINNED - Cushions

Postby Burgerman » 23 Feb 2021, 09:45

Its worse... Most cushions are 1024 sensors. Rohos one is 1380 sensors. And costs 10s of thousands of dollars.
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Re: PINNED - Cushions

Postby ex-Gooserider » 02 Mar 2021, 04:16

Burgerman wrote:Its worse... Most cushions are 1024 sensors. Rohos one is 1380 sensors. And costs 10s of thousands of dollars.


I was guessing conservatively at the number of sensors... But not all that far off really...

Given your numbers, and assuming a square mat, that would be 32^2 sensors on most, and 37+^2 sensors on the Roho... In approximate numbers, if sticking with the assumption of a 20"^2 mat, then it would be about 1/2 to 3/4" between sensors (probably some metric equivalent...) or a bit wider if the mat was bigger....

Either way, my guess is that nearly all the cost is in the mat, as the electronics in the rest of the unit looked to be mostly off the shelf hardware and some relatively standard software.... I would also guess that the software is doing at least some level of interpolation between adjacent sensors in order to get more 'virtual' points on the pretty butt pictures.

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Re: PINNED - Cushions

Postby Tomkilmore » 11 Mar 2021, 21:54

https://www.otstores.co.uk/p/systam_pol ... tegory/463

Hayley moved from a roho to the above cushion approx 3 months ago, after many years of a recurring pressure injury on her ischium, it looks like this cushion has sorted it. Very similar to the roho but with much thinner membrane. No more sweating in pain or limiting time up to 3 or 4 hours a day...amazing.
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Re: PINNED - Cushions

Postby Irving » 11 Mar 2021, 23:03

ex-Gooserider wrote:
Burgerman wrote:Its worse... Most cushions are 1024 sensors. Rohos one is 1380 sensors. And costs 10s of thousands of dollars.


I was guessing conservatively at the number of sensors... But not all that far off really...

Given your numbers, and assuming a square mat, that would be 32^2 sensors on most, and 37+^2 sensors on the Roho... In approximate numbers, if sticking with the assumption of a 20"^2 mat, then it would be about 1/2 to 3/4" between sensors (probably some metric equivalent...) or a bit wider if the mat was bigger....

Either way, my guess is that nearly all the cost is in the mat, as the electronics in the rest of the unit looked to be mostly off the shelf hardware and some relatively standard software.... I would also guess that the software is doing at least some level of interpolation between adjacent sensors in order to get more 'virtual' points on the pretty butt pictures.

ex-Gooserider

A colleague of mine is researching printable 3D pressure sensors (both normal and shear force) using graphene compounds and conductive elements embedded in 3D printed deformable silicon rubber structures. He reckons it should be possible to 'print' a pressure sensor mat approx 50cm x 50cm x 1.5cm containing sense elements on, say, a 4mm grid, giving a 128 x 128 array (16384 points). Since they are simply resistive devices a simple analog multiplexer and differential A2D converter 8-channel setup could easily scan the array several times a second.

Maybe sometime later this year or early next...
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Re: PINNED - Cushions

Postby ex-Gooserider » 16 Mar 2021, 03:20

Sounds like a good item if it makes it from the lab to the production floor (the problem with a lot of research is that it doesn't) However it seems unlikely to be something one can print on a typical hobby level printer due to the mix of materials....

Hope his research works!

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Re: PINNED - Cushions

Postby Chairman » 03 Apr 2021, 17:20

Varilite Evolution for me. Sat on most cushions over the 38 years of chairdom and can't get on with the Jay variants. I have a couple here to use temporarily on other chairs and the gel does nothing for me in terms of comfort. The Varilite is great and can be adjusted simply by a valve. If you're sitting on it too high just let out the air until you're satisfied, if you want the air back in, lift up and have someone to open the valve and it re-inflates. I've never had a Varilite puncture and they last years, in fact I can still sit on my cushion of 10 years and not notice it's age.

I wouldn't entertain a Roho based on the fact it's like jelly under your rump and transferring is unnecessarily difficult. Adjusting your position is made way more difficult if you can move. Rohos were always meant for those that can't move or lift themselves.
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Re: PINNED - Cushions

Postby Seajays » 03 Apr 2021, 18:26

I have sat on a Roho for 22 years with np problems , You must only get a Roho Quadro so the cells are locked . I am a double above the knee amp and have no problem to transfer
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Re: PINNED - Cushions

Postby Burgerman » 03 Apr 2021, 19:18

You must be better at it than me! I cannot transfer without a fight on the two quadros I have here. I always knew they offered the best pressure ulcer prevention based on looking at both the way they work and on hundreds of others pressure maps at my spinal injuries unit.

But as an active user the stability and ease of transfers on the Jay gel cushions mattered. As did the zero maintainance. And worry about bottoming out, or pnctures. So now I have decided that I am sick of being on a bed with pressure ulcers reccuring and so have no choice but to use roho, and a patient lift which is a royal pain in the backside (not literally). Note that NON of this has anything to do with comfort but pressure ulcer prevention or healing. So if you dont NEED a roho, esp if active, then a Jay2 or a jay fusion etc are better and almost as good with pressure. But if you have no choice, a roho it has to be...

Also, Varilite Evolution maps for pressure on most users slightly worse than jay2 and considerably worse than roho for peak pressure on the ischeals. It might well be more comfortable. But its almost garanteed worse for ulcer prevention than a roho. I know that from looking at dozens of comparisons as above. So I never tried one.

I might add that the least comfortable cushion for those that were testing it (spinal injuries unit plus others) that could actually feel it (I cant) was the best one for low pressure on the ischeal tuberosities. It was similar to this: https://www.permobil.com/en-us/products ... ct-cushion
Only more extreme. So comfort and peak pressure on the important bits do not always align.

The advantage of the deep roho's is that they can get you due to high levels of air immersion, to below 27mmHg across your backside. With no peaks above 32mmHg. Since its air infated the pressure is the same everywhere. Its not higher where immersed deeper. Not many other cushions can achieve this. This is the pressure that closes the blood flow in capilliaries. Hence my fancy pressure gauge/pump on the previous page. It allows me to be 100% sure that it is at the lowest pressure possible daily or weekly without bottoming out safely without doing further difficult hand tests. Remember that the barometer changes over a day or so. And so does the pressure in that cushion. The difference between capilliary closed and open can be 1mmhg variation.

If you are not struggling with ulcers this isnt important.
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Re: PINNED - Cushions

Postby Chairman » 03 Apr 2021, 20:52

Burgerman wrote:
Also, Varilite Evolution maps for pressure on most users slightly worse than jay2 and considerably worse than roho for peak pressure on the ischeals. It might well be more comfortable. But its almost garanteed worse for ulcer prevention than a roho. I know that from looking at dozens of comparisons as above. So I never tried one.

We are all built differently so maps to me are just that, maps. As far as I am concerned I have never had a pressure sore nor once needed to resort to bedrest in 38 years. There are many variables to this of course and I got out of a manual 'static' sitting chair full time enough years ago to give my body a rest and allow for weight relocation via tilt and recline which I believe has helped no end. Age dictates too that we cannot sit in one position most of the day except for the occasional lift without extreme pressure on one area, eventually something has to give.

Rohos are not for active paras or tetras, they might well help AFTER the sore but will also reduce activity which is equally important to recovery and loss of movement prevention. The object is to prevent sores in the first place and your Jay2 clearly failed you, mapping or no mapping which I am not surprised at having tried them.

Compatibility cannot be decided either comparing different injuries/conditions. A paraplegic transfers differently to a tetraplegic (if they transfer at all independently) to a double above the knee amputee.
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Re: PINNED - Cushions

Postby snaker » 04 Apr 2021, 04:00

I am fighting a sore. I bought a Vicair and it did not help, then I bought a Roho. After ordering, I recognized that Roho cushion was not quadro and I thought I wasted my money. It arrived 2 months ago and I tried it. It is really good in preventing pressure sore. I only use it when going outdoors, the sitting time is usually 5-6 hours but the sore only get wet a little. After the sore occurs, I always sweat a lot. But sitting on that Roho, I do not sweat. Although it is not a quadro but sitting is fairly comfortable and stable.
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Re: PINNED - Cushions

Postby Burgerman » 04 Apr 2021, 07:49

They work. Because they are one of the only cushions that allow a less than 27mmHg pressure across the most submerged (and all) bits. If sized and set correctly. This is critical. And cant be reached by any other type of cushion.

The problem with any types of foam is that they increase pressure the deeper your backside pushes into them. With all air, and no foam at all, the pressure on the bits of your backside that are submerged is exactly the same on the bits that are not. And in getting all of your backside below 27mmHg this is critical.

That pressure in the air cushion, is equal everywhere. So if you are sunk deeply into the cushion so that only 20mm or less remains - pressure is low enough that it does not close off the capilliaries in your skin even at the deepest parts. JUST. A fraction too much air in a roho and thats not the case. Its very critical to a couple of mmHg. So be sure you are sat very deeply into the cushion. This is the reason I bought that pressure monitor attached to the pump. I can get around 1 to 2 mmHg below that critical point. With around 10 to 15mm remaining before bottoming out. This magical pressure where no skin damage occurs is around 27mmhg. Anything below that and you are curing a sore. And not making it worse. This isnt possible with any other type of cushion.

Also theres this. Which is from gooserider,

One of the things I have heard about Roho's is that it is absolutely critical that the size of the cushion match the size of the butt that is sat upon it...

If the cushion is bigger than the butt, all the air moves to the un-sat-on cells and the sitter bottoms out unless very high pressures are used...

If the cushion is smaller than the butt there is no place for the air to go, so you end up w/ higher pressures in the cushion, while the excess butt droops over the edges...

The cushion needs a 'Goldilocks' style fit that is "just right"....

ex-Gooserider


Which is absolutely true. The little gauge I use shows this when experimenting on my two 19 inch x 20.5 cushions with my petite (small bum) female freind, and my somewhat well built relation. When at that 15mm hand gap point, they both need MORE pressure than I do. Meaning above that 27mmHg point.
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Re: PINNED - Cushions

Postby Sfischer11 » 26 Apr 2021, 18:50

Hi there,

The ROHO Hybrid Select Cushion is new and made with a combination of foam and air. It uses the ISOFLO Memory Control for the dual zone overlay and the removable IT air insert.
Here is a direct link to this item - https://hub.permobil.com/roho-hybrid-select

EDIT - Burgerman
I removed the two commertial spam links and instead linked to the cushion by the manufacturer. Because I dont like spammers. But the cushion looks interesting all the same.
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Re: PINNED - Cushions

Postby ex-Gooserider » 27 Apr 2021, 01:50

One idea that I'm sort of surprised isn't offered (unless maybe it was tried and didn't work) is one that has been offered for years to campers for sleep mattresses...

The big name was "Thermarest" but there were a lot of other brands doing the same thing... Basically they had a pad of fairly soft and spongy foam inside an air bladder... The foam gave the bladder a certain amount of shape, and also made it partly self inflating, but also limited how much the air could move around. This kept the sleeper from squishing the air out of the way and touching down, and also kept the air from circulating cold from the ground up to the sleeping bag. At the same time it was easier to pack as you could let the air out and squish the foam down much more than a plain foam pad would let you do.

It also claimed to give some support if it turned into a snake and went "HISS" in the night.... I used one when camping at motorcycle rallies for years and never had any problems with mine, so couldn't say whether that part worked or not.

Seems like it would be an interesting design for a chair cushion in that it might solve the problem that Roho's have of the air shifting around when trying to transfer or do pressure relief...

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Re: PINNED - Cushions

Postby Burgerman » 27 Apr 2021, 06:53

This kept the sleeper from squishing the air out of the way and touching down


Then thats the very thing that a roho it attempting successfully to prevent That would be the point where the deepest immersed bits, the isheal tuberorities need to have the same pressure - preferably less than around 30mm mercury, as thats the approx point that closes capilliaries and stops blood/oxygenation. Adding any extra load (the foam) increases this. Its actually very difficult to achieve this 30mmhg level even on a roho. It must be sized perfectly and an average human, and very careful setup. I made a gadget to read this as you inflate or deflate the cushion.

Being fat, with a relatively skinny boney backside, I cannot achieve that. The best I can manage is 36mmhg with only 10mm approx in the hand test... If I increase that to 15mm (just a 5mm hieght increase) the gauge reads 43mmhg. MUCH worse. Remember that this is air pressure so its the same pressure everywhere inside that cushion. The deeply immersed parts do not see higher pressure at all. Thats why rohos work. Addding ANY foam defeats this.

Inside an air cusion that is all seperate partly filled rubber cells, with no single surface tension like your air bed, the same ass presure is seen everywhere. Same as if a seating mapping (unafordable device is used). But now not needed. Add foam and the deepest immersed bony parts will read higher than the rest of your ass... A definite no no.
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Re: PINNED - Cushions

Postby Frank » 02 May 2021, 10:47

https://www.youtube.com/watch?v=IdcdkLjFt0w&ab_channel=SpinLife

In this video they explain “what is dry floatation?” They say when the Isoflow valve is closed to achieve position and stability, its therapeutic effect is compromised (becomes less effective). So if you need to achieve the lowest pressure you have to leave the Isoflow valve open.
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Re: PINNED - Cushions

Postby Burgerman » 02 May 2021, 11:40

Theres 2 ways to look at that. If you want the lowest cushion pressure then you have to keep deflating it to lower the pressure. Until theres only say 10mm of gap between the lowest part of you and the base. Now this gap is small. You do this while say in your "normal" position. All the air is at the same pressure throughout the cushion. And so closing the valve has no affect of the pressure at all. Its the same 30mmHg everywhere if thats the lowest you can achieve.

Now, with valve closed, you lean left as I do when watering plants for e.g. The gap in the laft side gets a little smalley, but thats only because the air cant move. So pressure temporarily increases on the left isheal bone. But it doesent bottom out.

In order to get the same safe gap when I lean left to water the plant with the valve open, then I need to have a 25mm gap between ass and base to start with. And that means that the pressure might need to start at 45 instead of 30... So I dont think they are correct. It all depends on ACCURATE initial setup. Including testing while leaning. In other words you can start with a lower pressure in the first place if you lock the air in place with a valve.
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Re: PINNED - Cushions

Postby Burgerman » 04 May 2021, 01:15

This is what I use to determine pressure as I sit in the chair. I madeit from ebay parts. It allows me to increase or decrease the pressure and watch it change as I release air ir pump more in.

Because of extensive "plastic bag with hand in it" testing on multiple days with 3 different carers, and averaging the results I can say that when I have 10 to 12mm between me and the chairs base, at my ischeal tuberosity bones, the pressure is 36mmHg when my arms are on the armrests. (42 with then lifted.).

So that now I can check myself, get it exactly right, as often as I want. On my own. With no plastic bag/hand testing.

With a smaller gap, say 5mm I can't test. Fingers are thicker! But you wouldnt want to. With a bigger gap, say 20 to 25mm, the presure is a lot higher. Approx 44 to 46mmHg. So aiming for a 10 to 15mm gap makes a lot if difference. Remember these are MY figures for my backside on my cushion. You will need to determine your own from the hand tests.

You cannot do this without a quality pump. The one supplies isnt good enough. And you need a couple of adjustable valves, a T, and a quick release "fuel" connector so that it works as an airtight swivel to allow easy use of the cushions on/off valve. Test with the ISO valve on the cusion open. Lock it when finished and yourself in the correct position.
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Re: PINNED - Cushions

Postby Frank » 04 May 2021, 09:50

In this video somebody refitted a Smart Check to a Roho cushion, I don’t know if it is useful?
https://www.youtube.com/watch?v=4gxef3D ... l=C.Hamish
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Re: PINNED - Cushions

Postby Burgerman » 04 May 2021, 12:39

It could be if you aready have one. But 4 things. The smartcheck doesent tell you the range of pressures that it deems OK. And it must be very large as even lifting an arm make a pretty big difference. It also doesent tell you the actual pressure. And so you dont know if its well above or a safer below 25 to 35mmHg. And its way more expensive too. And I dont think many would want to cut their cushion...

This way you dont have to.
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Re: PINNED - Cushions

Postby Burgerman » 05 May 2021, 06:35

I could for e.g. sit a user on a cushion. Your own, your size, your ass, your weight for e.g. And then very carefully, increase or reduce pressure so that you have 10mm gap (the plastic bag/finger test as explained by Roho), to determine exactly what pressure this is (above ambient atmospheric). This manometer can do comparitive and direct measurement. The atmospheric pressure makes a difference an it varies. So after doing this test half a dozen times, on different days you end up with a RANGE of figures as you dont always sit the same exact way.

So you would remove any pressure readings that were obviously too high or too low due to error measuring with the fingers. That leaves a bunch of quite similar central figures. Average these figures. This might give say 32mmHg pressure.

I could now send you away with a figure of 32mmHg written down for correct pressure with arms on armrests and correct footplate position, ISO valve open.
That is the pressure that allows the lowest possible pressure for YOU against your backside, on YOUR cushion at your current weight. Adding more increases capilliary pressure and = sores. Allowing less will allow that 10mm to decrease and you may bottom out. And once seated correctly, level, get a carer to slide that ISO valve closed. As that allows the 10mm finger gap to be safe even when leaned over left/right.

In this way you should never need to redo the finger test gap, and can adjust the pressure back to your 32mmHg to ensure the best safest pressure/gap at any time. Maybe once a week. Just remember to OPEN the ISO valve each time. And re-close it later.
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Re: PINNED - Cushions

Postby Frank » 10 May 2021, 13:34

BM, I refer to the picture where I marked in blue. Are these adjustable valves? Can you please explain how they work? Where can you buy it? Thank you.
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Re: PINNED - Cushions

Postby Burgerman » 10 May 2021, 14:37

EBay 4mm valves used for aquarium stuff. Cheap. The tube is also 4mm aquarium. The part that goes onto the cushion is silicone 8mm.
The connector near the cushion is a fuel disconnect for motorcycles, from eBay. One half 8mm the other 4mm. So that it spins freely when attaching to the cushion on/off valve.

Be sure you get a GOOD pump or the air will escape slowly as you try to read the pressure after hand test. Mine's the 3rd different one I tried. I also added silicone grease to the pump.

The small valve near the pump ringed in blue, allows the pressure in the cushion to be lowered.
The one near the gauge is only cracked open a fraction. So as to smooth out the pressure changes as you move on, or pump up the cushion.

You may note that there are two long tubes joined by a T. The pump joins at the cushion end so that the pulses of pressure dont go directly into the gauge. As that may damage it - so it must go all the way up the other tube... The Small valve at the gauge also helps prevent this happening.
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Re: PINNED - Cushions

Postby fishinjunky » 12 May 2021, 12:46

I was recently part of a zoom group with a company developing a really interesting alternating air cushion. the group consisted of other wheelchair users that like me constantly deal with pressure sores. We were able to give our input on what we want in a cushion. its not in development yet but when it is it will be very affordable and will help prevent pressure sores dramatically. Here is the website

http://wavetherapeuticsinc.com
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Re: PINNED - Cushions

Postby Burgerman » 12 May 2021, 13:31

I bought/made a cushion(s) very similar to that a year back. It worked quite well. Theres a thread here with pics somewhere. But still I think the roho works better IF configured correctly.
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Re: PINNED - Cushions

Postby fishinjunky » 12 May 2021, 14:46

Burgerman wrote:I bought/made a cushion(s) very similar to that a year back. It worked quite well. Theres a thread here with pics somewhere. But still I think the roho works better IF configured correctly.


thats cool. I also agree with you on ROHO ive been using them for years but I was over inflating causing sores. once I realized I was making the ROHO to firm I started letting more air out and I healed up in no time. I like ROHO alot now
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Re: PINNED - Cushions

Postby hobie1dog » 12 May 2021, 19:31

Burgerman wrote:I bought/made a cushion(s) very similar to that a year back. It worked quite well. Theres a thread here with pics somewhere. But still I think the roho works better IF configured correctly.


viewtopic.php?f=2&t=8081&start=60
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Re: PINNED - Cushions

Postby fishinjunky » 14 May 2021, 13:59

Burgerman wrote:This is what I use to determine pressure as I sit in the chair. I madeit from ebay parts. It allows me to increase or decrease the pressure and watch it change as I release air ir pump more in.

Because of extensive "plastic bag with hand in it" testing on multiple days with 3 different carers, and averaging the results I can say that when I have 10 to 12mm between me and the chairs base, at my ischeal tuberosity bones, the pressure is 36mmHg when my arms are on the armrests. (42 with then lifted.).

So that now I can check myself, get it exactly right, as often as I want. On my own. With no plastic bag/hand testing.

With a smaller gap, say 5mm I can't test. Fingers are thicker! But you wouldnt want to. With a bigger gap, say 20 to 25mm, the presure is a lot higher. Approx 44 to 46mmHg. So aiming for a 10 to 15mm gap makes a lot if difference. Remember these are MY figures for my backside on my cushion. You will need to determine your own from the hand tests.

You cannot do this without a quality pump. The one supplies isnt good enough. And you need a couple of adjustable valves, a T, and a quick release "fuel" connector so that it works as an airtight swivel to allow easy use of the cushions on/off valve. Test with the ISO valve on the cusion open. Lock it when finished and yourself in the correct position.


I wish this was commercially available to purchase. Im not sure if I could get it assembled correctly but I would really like to buy one. I have a couple ROHO smart check devices but they are really useless. If you ever decide to take a commission to build one I would pay in advance.
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Re: PINNED - Cushions

Postby Burgerman » 14 May 2021, 14:29

Its plug and play. I can give you all the links...
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Re: PINNED - Cushions

Postby fishinjunky » 15 May 2021, 23:54

Burgerman wrote:Its plug and play. I can give you all the links...


Thanks that would be awesome
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Re: PINNED - Cushions

Postby Burgerman » 16 May 2021, 05:43

UPDATED!!! and refined after use.

Gauge no batteries... https://www.amazon.co.uk/gp/product/B01 ... UTF8&psc=1

Pump. https://www.amazon.co.uk/gp/product/B08 ... UTF8&psc=1

SW0789ID6 https://www.ebay.co.uk/itm/164492914906
+
M789ID4 https://www.ebay.co.uk/itm/164492914906

Tube plus fittings https://www.ebay.co.uk/itm/114426037677

BIG photo download/file.php?id=15573&mode=view

Valves https://www.ebay.co.uk/itm/264957842401 These need a little silicone grease on threads to stop them slowly leaking.

You need short bit of soft tube to fit onto roho. Its 6 or 6.5mm ID and I forget which so use existing bit, or order 6mm and 7mm just in case here. You may need to shop around. https://www.ebay.co.uk/itm/402693510356 for e.g.
This stuff varies. The correct size is already on your roho pump. You can use that.

You also need some small cable ties, heatshrink, or velcro strap to make it neat... Or insulation tape but that comes unstuck over time. I used heatshrink with care! With my picture above it will all become self explanitory. Not the cropped one!

Then waste a set of batteries and learn how the meter works. Learn everything it does. Learn how to turn on backlight. Learn how to set to DIFFERENCE rather than absolute, and learn how to zero it. So you can do it from memory easily. And then you are good to go.
Turn backlight on.
Set it to mmHg.
Set to Differential pressure (or zero it every time). Or the atmospheric pressure variation day to day will mess up the reults.

Make a lot of notes, on different days after setting with the hand test as low as you dare to go. Keep and date the figures you end up with. Helpers are very variable! Average the figures. Test with arms lifted seperately. And arms on arm tops seperately. It makes a huge difference. After a week you should have enough to get a good average - correct - pressure without the hand test.


EDIT:
My pump leaks air and pressure falls over time... So allows the pressure to fall slowly while you are doing a hand test. So:
https://www.ebay.co.uk/itm/283318275086
Cure, fit one of these directly after the pump. 3.8 to 4.8mm - I ordered 3 different ones to find out!

Or, These work too. https://www.ebay.co.uk/itm/183568499099

NOT - https://www.ebay.co.uk/itm/265108250161
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