[ShelaVenna]

The level of suction is important but it’s not as important as a sensor. If your pump just pumps continuously, the pressure will increase continuously. Maybe there’s a theoretical maximum I don’t know about because I’m absolutely not a physicist or an engineer, but I know for a fact that any vacuum pump, no matter how weak, will eventually create pressure far outside the safe zone if it pumps continuously without releasing. You need a “smart” pump, meaning a pump with a sensor that will tell it to turn off when the pressure rises above the target range, and back on again when it drops below the target range. There are a few people who made their own programmable smart pumps, but I’ll be honest, I found them on penis pumping forums back when I tried looking into this a long, long, time ago. I don’t have a penis, but I figured that wasn’t relevant lol. I have no idea where to find those posts now, and I don’t think I ever found an actual guide about how to build one. I quickly realized it was probably too difficult a project for someone with absolutely no experience with building electronics. If you think you can figure out how to build one, there may be some kind of guide out there, probably buried deep in a penis pumping forum’s archives, so you’ll have to swim through a sea of dick pics to get to it. On the other hand, James98, who is already in this thread, has built at least 2 smart breast pumps. I have a feeling the reason he’s never posted a guide is because it’s very complicated and would lead to a flood of questions from people who have never even used a power tool. I don’t wanna speak for him though, let alone volunteer him to do anything he didn’t agree to. 

I forgot to mention that you can safely use a pump that has no sensor, as long as it continuously turns on and off in short bursts, and has a very low pressure setting. Nursing pumps work this way, but they’re not designed to run continuously for hours. There may be a way to get around that limitation and force a nursing pump to run for much longer periods, hopefully without causing the machine to seriously overheat, but I have no idea.

Btw, I’m assuming you already read that a wound vac can be used, and you’re just looking for a cheaper alternative. If not, go to the thread called “Evebra finally available”, and check out the wound vac mentioned there. Not all wound vacs will work for our purposes, but that one will, and it’s apparently a pretty damn sturdy workhorse. People who have used it seem to love it. It’s called the Deroyal Pro II, and there should be some available on Ebay. Don’t feel bad about haggling with the seller a little, within reason, and keep in mind that a lot of sellers will send you a discount if you wishlist an item but don’t immediately purchase. I haven’t tried the Deroyal pump myself because I already own an ancient Brava smartbox pump. They’re basically impossible to find nowadays. I lucked out and bought what was probably one of the last ones ever posted online. I personally wouldn’t even bother trying to find another, but I guess it wouldn’t hurt to try, just don’t hold your breath.

[James98]

The level of suction is important but it’s not as important as a sensor.

I have not seen a pump advertised as having a sensor. BB pumps have settings, but it just changes the number of seconds it pumps before releasing.

I have been working on building one, and it turns out to not be as easy as I thought. I had hoped to sell them for $300, but now I think I will have to charge significantly more. Main problem has been to reduce sensor noise, that is the reading bounces  around too much and it takes careful design to make it stable and accurate. Currently varies about +/-1kPa which is probably good enough.

[ShelaVenna]

Sorry. I thought the pumps you built had sensors. Interesting. Like I said, pumps that don’t have sensors, but that cycle on and off quickly, releasing pressure, can also work. I hope that made sense. I know I tend to use the wrong terminology. If you can make a pump that cycles on and off and can pump for many, many hours at a time, you’ll be filling the same niche as the Evebra. The Evebra pump is extremely unreliable according to people that have tried it, so there’s definitely room for a better alternative. I know you seem to favor higher pressure pumping, but that style of pumping doesn’t really require a machine, and not many people will be willing to invest a lot of money in something they don’t need. People who choose to pump for many, many hours a day would benefit the most from an electric pump, and be more motivated to spend a lot of money on it. Of course, you don’t have to do any of this. I know this is just a hobby for you, and if you’re not interested in making that style of pump, don’t feel bad.

[James98]

Sorry. I thought the pumps you built had sensors. ... I know this is just a hobby for you, and if you’re not interested in making that style of pump, don’t feel bad.

You are right that this is just a part time hobby atm. But I have only made one prototype prior, and it does have a pressure sensor and an electric motor. I am currently working on my second one with a smaller motor, it will still go to high pressures, just takes longer. But the whole point is my design has many user settings, so you decide how much pressure you want. Also my latest version allows setting and viewing pressure in kPa, in-Hg, and cm-Hg. In Manual mode it will maintain the pressure you set until you turn it off. In Automatic mode it cycles. To be clear, in Manual mode it will pump to the set pressure and turn off. If there is leakage and after some time the pressure drops, the motor will run briefly to bring the pressure back up. If you want to, you could set it to low pressure and have it on all night. I will have to perform endurance tests to find out if this smaller motor holds up.

[ShelaVenna]

That’s great to hear, James. There will always be interested potential buyers here, IMO. It would be hard to make a smart pump worse than what Evebra is currently selling. If you start selling, I will definitely recommend that people get in contact with you.

[tara zish]

I know for a fact that any vacuum pump, no matter how weak, will eventually create pressure far outside the safe zone if it pumps continuously without releasing. You need a “smart” pump, meaning a pump with a sensor that will tell it to turn off when the pressure rises above the target range, and back on again when it drops below the target range.

Thank you for your explanation. It's very interesting and I understand a lot better now, so I really appreciate your input. It seems that my original idea would be quite easy to implement, and would definitely work, but just wouldn't be safe.

[Bella J]

It would be hard to make a smart pump worse than what Evebra is currently selling.

As a newcomer, I wondered what your criticisms were of the Evebra.

[ShelaVenna]

They’re other people’s criticisms. I’ve never even owned an Evebra. I owned a Brava at one point, an almost identical system. I liked Brava, but the pump is delicate. Apparently the Evebra pump is even worse, because it breaks constantly and has to be replaced. Several people have posted about their experiences with the Evebra pump on here. Evebra does seem to be a pretty respectable company at least. So far they’ve been replacing the pumps quickly without blaming the customers or being difficult. That’s not good enough though, because taking breaks from pumping can set back your progress by a lot. Hopefully they’ll be able to get better quality pumps soon. If they don’t, I can’t recommend buying from them, unless you’re comfortable with buying and using a different pump while you wait for Evebra to send you a new one. On the other hand, you might be able to just suck the air out, and use an airlock or a simple clip to seal the tubing. That method has never worked for me though, even in combination with the Brava cups (very similar to the Evebra cups) that are much, much better at holding a seal than other styles of cup. IME, the cups always lose suction as I move around slightly in my sleep, and without a bra to hold the cups in place, and a “smart” pump that kicks back on when it senses a loss of suction, they just fall off. I’ve tried putting a bra over the cups too, but that didn’t help maintain suction. It just stopped them falling and possibly cracking. I hope that made sense.

If you’re interested in the Evebra, it MIGHT be worth it to buy a set of airlock Noogleberry cups, tubing, their silicone padding rings (their foam rings suck), and a massively oversized zip-front sports bra instead. You can just suck the air out by mouth. That method didn’t work for me, like I said, but it has worked for other people, and it’s by far the cheapest way to vacuum pump while sleeping.

[blueheart]

It seems that my original idea would be quite easy to implement, and would definitely work, but just wouldn't be safe.

If you just wanted something for little cost it's not difficult to put together a homemade setup which would do the job. It's been done before that someone made a pump even including domes for no more than $15. But in your case you want a Brava-Evebra type device which is something else entirely. That's the problem here, that you want something which would work with very low pressure for a long time without you having to operate it.

[tara zish]

Yes that's exactly what I wanted, so I could use it whilst I was sleeping. Hours of pumping just isn't practical for me otherwise. As I said earlier, it would be easy to do and could be done at minimal cost, but unfortunately as I now understand it wouldn't be safe. Since safety is the paramount concern that's brought my project to an end, but I've learnt a lot from this thread so I've still gained from my time here.