Date   
Re: BITX6.1 BFO setting

kbtgw
 

Thanks guys, that is what I needed.
   Les,  K2TGW

Re: Elon Musk: Should Have 1000 Ventilators Next Week, + 250,000 N95 Masks For Hospitals Tomorrow — CleanTechnica Exclusive | CleanTechnica

Ken Hansen
 

Is there no better forum to share this information?

Ken, N2VIP

Mail

Christopher Miller
 

I actually agree. I was considering a Chinese hand held because it’s probably as expensive as the tuner and dummy load. But selfishly I want a proper hf setup.

KF4FTR

Elon Musk: Should Have 1000 Ventilators Next Week, + 250,000 N95 Masks For Hospitals Tomorrow — CleanTechnica Exclusive | CleanTechnica

Arv Evans
 

Re: Mail

_Dave_ AD0B
 

Neat letter

For emergencies I think. 2 meters is king. Really fills in some of the hf gap
--
73
Dave
ADOB
Raduino bracket and Ham_Made_Keys

Mail

Christopher Miller
 

I thought this would be interesting since I will be using a ubitx v3. If someone could send me a link to the wrap tuner with the led again I will be in your debt.

Re: BITX6.1 BFO setting

Evan Hand
 

There is an online video and webpage to show you have to both calibrate the frequency and to set the BFO:

https://www.youtube.com/watch?v=t6LGXhS4_O8&feature=youtu.be
https://www.hfsignals.com/index.php/bfo-tuning-aid/

As Barry stated, you can start with the 11.055 setting and then use the web page to fine-tune.

Hope this helps.
73
Evan
AC9TU

Re: BITX6.1 BFO setting

barry halterman
 

Basically it is personal preference on received audio. For the BFO setting, you can start at 11.055.5mhz  and go from there.
Barry
K3bo

On Mon, Mar 23, 2020, 1:45 PM kbtgw <k2tgw@...> wrote:
I may have changed the BFO setting on my BITX6.1.  Is there default value ?
   Les,  K2TGW  k2tgw@...

Re: Ventilator

Tom, wb6b
 

Hi,

While there is no substitute for professional level expertise to guide these projects, like Gordon's, for people interested in a taste of the issues involved in ventilators, here is a link. Balancing simplicity with safety looks like a major consideration.

It looks like there are many projects working to solve this and other upcoming critical needs. Different concepts to address different situations and how much support, clean compressed air lines O2 and such, to support the ventilators are available in the facility. 

https://www.youtube.com/watch?time_continue=15&v=gk_Qf-JAL84&feature=emb_logo

When some of these design come to deployable states, folks, like myself, who have a small assortment of electronic/computer parts could possibility construct a few for their local area, before parts are ordered, arrive and construction could be organized on a larger scale.

Tom, wb6b

Re: Ventilator

Jerry Gaffke
 

Have thought about this for all of 10 minutes.
A few things come to mind, perhaps already considered

My primary concern:  25psi will pop a lung.
Perhaps an extra fail-safe that senses pressure going into the lungs, 
shuts everything down and sounds an alarm if pressure goes too high?
Though scuba gear has proven reliable enough in this regard.

Likewise, that same pressure sensor can be used on exhale, sound an alarm if too high,
A diseased lung will likely be sending out more than just air,
which could plug a valve or tube.

As Bill Cromwell suggests, all valves (not just a sample) should be tested for gas leakage
with some sort of jig before installing them in a ventilator.
An inhale/exhale pressure detector should help detect failures during use.
I doubt there will be a spec on lawn sprinkler valves for gases.

And if operating valves below the spec voltage, then all should be tested to operate well
at the reduced voltage.  Test should be conducted at the expected worst case temperature.
I would consider boost mode switcher (better: buck-boost) that can be cut back to 12v (or less)
once the valve has been actuated, more or less as Gary and Gordon have suggested.

Operating from 12vdc seems ideal.  These need to operate where mains are not reliable. 
Keep power requirements to a minimum, may have a bunch of them operating off
a single vehicle battery.

Vet the software carefully, and keep egos in check if your stuff gets criticized.
Has to be perfect, which means best to keep it as simple as what does the job.
Perhaps a group of 5 coders take a vote on what passes?

Don't use $2 Nanos unless they all get carefully tested, reports in this forum
show that some getting shipped may mostly work, but suck 2x the current.
I'd tend to put the processor and power supply on a single auto-stuffed main board
to reduce interconnections, buying parts only from trusted distributors.
Though perhaps initial units have to use whatever is on hand, speed is essential.

Monitor current into the finshed board when qualifying, many faults show up as excessive current. 

Needs to be well protected, so must have a cheap but solid enclosure for the electronics.
Perhaps size the board to fit the top of a food tin?
Or does the enclosure need to be large enough to protect the valves?

Good luck to all!

Jerry, KE7ER


On Mon, Mar 23, 2020 at 12:40 AM, Gordon Gibby wrote:
Ashar & Jack — you guys please do software.  make it simple!!!   be finished by Wednesday morning.  when I wake up for real at 1000 zulu I will compile the medical  requirements. 
 
The valves can be driven with 12 to 14 V DC successfully.   They snap in at a minimum of 10 to 11 VDC.  I think we can run the circuit with a buck boost converter from Amazon creating 13.8 VDC from a 12 V battery being continuously charged by a Walmart 2Amp battery maintainer— We have several digipeters operating for years that way
 

I will also send out the schematic, which involved arduino output to 20 K ohm resistor driving the base of a 2n3904.     2N3055 (all I could find in the house) switching the valves (snubber diode on the valve) with series 1200 +100 ohms from +13.8 to the base of the 2n3055;  The 2N3904 collector connects to the 100 ohm tap and shorts it to ground when energized by the Arduino through the 10 or 20 KOHm resistor.     Worked perfectly here.  I have not tested it across the temperature range.  My goal was to be certain the transistor is fully saturated when “On”.  Ashar — please do the circuit board & case.  
 
Valves
The valves have 43 ohms of DC resistance.  Although specified for 24 V AC, two out of two worked perfectly by the time 12 V DC had been reached.   I urged the adoption of 13.8 V DC to give some margin.  They get warm during use
 
I used a three terminal 5 V regulator to feed the Arduino.   Fed by 13.8, it did OK without a heat sink, but it might be nice to add a small one
 
The mechanical engineer, Dave Lizdas, used a fascinating balloon system inside the expiratory limb to automatically occlude it during inspiration.
 
I am concerned that will be difficult to replicate and may be subject to fouling  by respiratory secretions.  Therefore I had provided for two sprinkler valves, one in the inspiratory circuit and one in the expiratory circuit.  Inspiratory Limb is fed by compressed gas at up to about 25 psi, and has mechanical adjustable resistance in series—- pvc valve from Home Depot.   Expiratory limb goes to some form of positive and expiratory pressure, can be as simple as flexible tubing exiting underwater at a depth of 5 to 20 cm underwater.   Spring loaded valve is another possibility.   
 
Open inspiratory valves and close expiratory valve: patient’s lungs are inflated.  
 
Close inspiratory valve, open expiratory valve, patient exhales.
 
Sedated patients can be ventilated with a simple open loop system just like that.
 
Conscious patients will buck that system if not completely worn out.   Typical “ assist mechanical ventilation “ detects a drop in pressure of about 3 cm-5cm of water Caused by the patient initiatingcaused by the patient initiating an inspiration,  and then immediately kicks in to ventilate a patient with a total volume of adjustable from 400 to 900 mL.    We have not yet written the software for that at all 
 
Off the top of my head, those are the two major modes of operation. 
 
more information when I wake up for real. 
 
Gordon
 

BITX6.1 BFO setting

kbtgw
 

I may have changed the BFO setting on my BITX6.1.  Is there default value ?
   Les,  K2TGW  k2tgw@...

Re: Ventilator Project

Bill Cromwell
 

Hi,

I applaud offers of help shown in this thread. I cannot offer much except some information about the differences between water handling and air (gas) handling. More than 50 years ago I ran tests (by the thousands) on the water jackets of automotive engine cylinder cases. We tested with air. Because gasses can leak more easily that liquids the test pressurized the engine water jacket to a few PSI with air and then measured, if I recall correctly 10 or 15 seconds. The air pressure was allowed to leak down a specific amount and if that was exceeded the water jacket failed (the entire cylinder case failed). Other personnel looked for repairable causes or the parts were recycled. The air could leak that specific amount of air and would NOT leak fluids - the engine coolant.

The whole point is about those lawn sprinkler valves. The specs for those should be examined for their performance with gasses - air and oxygen. I only mention this to try and help so the project does not go astray.

We just got the governor's order to stay home except for "essential" needs like grocery getting. My XYL and I have already been doing that with just an official guideline. I have been out out for food twice in the past two Everybody please help prevent the spread of this ugly virus. I am pretty sure it will be a mere inconvenience for me if I get it but I would feel terrible if I passed it along to somebody who then died from it.

73,

Bill KU8H

On 3/23/20 9:26 AM, Jack, W8TEE via Groups.Io wrote:
Could those who are part of the "Ventilator Project" please use the group mailing list or my email
    jack52443  AT  yahoo.com
If you want to post on this Forum, that's fine, but just cc me using the private email address so I can archive our emails.
Thanks!
Jack, W8TEE
--
bark less - wag more

Re: Ventilator

VU3WTJ
 

Hi this is VU3WTJ from India, I'm into medical research, data analysis and instrumental design for last 7 years and got personal patents also. please mail me for  medical verification and correction of fabricated device and statistical establishment of result. 


Dr. Sirsendu Ghosh
+91-8447306472



On Mon, Mar 23, 2020 at 2:03 AM Gordon Gibby <docvacuumtubes@...> wrote:
A bit off topic!  I got asked to help build a ventilator for a low-cost application to save lives in COVID-19. A few brilliant engineers at the University of Florida are building a ventilator using cheap lawn sprinkler valves & pvc pipe  to direct compressed oxygen gas.   They needed a control system to manage the inspiratory and expiratory valves.

With What I have learned from Farhan and everyone here, I suggested the Arduino was the way to go;

Last night and today I started building the little transistor drivers to handle the sprinkler valves. The only NPN power transistors I could find in the entire house were 2N3055s.  Then I wrote a simple program to read a potentiometer to adjust ventilatory rate, and for starters,  set the I to E ratio at the normal 1 to 2.  Using the potentiometer, the respiratory rate can be varied from 10 to 30.   They have simple spring mechanisms to create positive end expiratory pressure.  The prototype is working on my kitchen table, and I’m waiting for the mechanical engineer to drive over with the plumbing apparatus and the valves.

Your building this open source, some of you really bright folks might want to jump in and help them with the software, if so email me and I will help get you into the group.  my part was just the simple transistor switches.

Ashar— We may have a new product for you to build quickly.  And I’m sure you could make it a lot better


Gordon Gibby KX4Z



Re: Ventilator

VU3WTJ
 

Hi this is VU3WTJ from India, I'm into medical research, data analysis and instrumental design for last 7 years and got personal patents also. please mail me for  medical verification and correction of fabricated device and statistical establishment of result. 


Dr. Sirsendu Ghosh
+91-8447306472

Re: Ventilator

KE0GYC
 

I work for a company that machines smallish parts in high quantity with CNC mills and lathes.  My supervisor has asked a couple of us to brainstorm ideas for things we could make to help in this pandemic.  If there are any small machined parts needed for this project, please feel free to pass them along.

Ventilator Project

Jack, W8TEE
 

Could those who are part of the "Ventilator Project" please use the group mailing list or my email

    jack52443  AT  yahoo.com

If you want to post on this Forum, that's fine, but just cc me using the private email address so I can archive our emails.

Thanks!

Jack, W8TEE

--
Jack, W8TEE

Re: Ventilator

Gary Anderson
 

The holding voltage of the sprinkler solenoid valve is probably lower than the activating voltage. 
This measurement may be very useful to the others working on the project.

This may lend itself to a quick PWM solution which will help on the temperature of both the driver bipolar and more importantly the 'valve' itself.  It will also lower overall power consumption.

100% peak for the valve turn-on for some period of time, then down to a holding PWM for the remaining time the valve is on.

Gary

Re: Ventilator

Gordon Gibby
 

Ashar & Jack — you guys please do software.  make it simple!!!   be finished by Wednesday morning.  when I wake up for real at 1000 zulu I will compile the medical  requirements. 

The valves can be driven with 12 to 14 V DC successfully.   They snap in at a minimum of 10 to 11 VDC.  I think we can run the circuit with a buck boost converter from Amazon creating 13.8 VDC from a 12 V battery being continuously charged by a Walmart 2Amp battery maintainer— We have several digipeters operating for years that way


I will also send out the schematic, which involved arduino output to 20 K ohm resistor driving the base of a 2n3904.     2N3055 (all I could find in the house) switching the valves (snubber diode on the valve) with series 1200 +100 ohms from +13.8 to the base of the 2n3055;  The 2N3904 collector connects to the 100 ohm tap and shorts it to ground when energized by the Arduino through the 10 or 20 KOHm resistor.     Worked perfectly here.  I have not tested it across the temperature range.  My goal was to be certain the transistor is fully saturated when “On”.  Ashar — please do the circuit board & case.  

Valves
The valves have 43 ohms of DC resistance.  Although specified for 24 V AC, two out of two worked perfectly by the time 12 V DC had been reached.   I urged the adoption of 13.8 V DC to give some margin.  They get warm during use

I used a three terminal 5 V regulator to feed the Arduino.   Fed by 13.8, it did OK without a heat sink, but it might be nice to add a small one

The mechanical engineer, Dave Lizdas, used a fascinating balloon system inside the expiratory limb to automatically occlude it during inspiration.

I am concerned that will be difficult to replicate and may be subject to fouling  by respiratory secretions.  Therefore I had provided for two sprinkler valves, one in the inspiratory circuit and one in the expiratory circuit.  Inspiratory Limb is fed by compressed gas at up to about 25 psi, and has mechanical adjustable resistance in series—- pvc valve from Home Depot.   Expiratory limb goes to some form of positive and expiratory pressure, can be as simple as flexible tubing exiting underwater at a depth of 5 to 20 cm underwater.   Spring loaded valve is another possibility.   

Open inspiratory valves and close expiratory valve: patient’s lungs are inflated.  

Close inspiratory valve, open expiratory valve, patient exhales.

Sedated patients can be ventilated with a simple open loop system just like that.

Conscious patients will buck that system if not completely worn out.   Typical “ assist mechanical ventilation “ detects a drop in pressure of about 3 cm-5cm of water Caused by the patient initiatingcaused by the patient initiating an inspiration,  and then immediately kicks in to ventilate a patient with a total volume of adjustable from 400 to 900 mL.    We have not yet written the software for that at all 

Off the top of my head, those are the two major modes of operation. 

more information when I wake up for real. 

Gordon





On Mar 23, 2020, at 00:24, Ashhar Farhan <farhanbox@...> wrote:


I had mailed some snippets of the code to sem. I am back in action now. Is there a source control or a repository of sorts for this? I would like to get the software sorted out asap.
- f

On Mon 23 Mar, 2020, 7:09 AM Jack, W8TEE via Groups.Io, <jjpurdum=yahoo.com@groups.io> wrote:
You're on the list.

Jack, W8TEE

On Sunday, March 22, 2020, 8:28:11 PM EDT, Howard Fidel <howard@...> wrote:


I am a medical device expert. If I can help in anyway, let me know. You can find my bio here:

http://w2hff.xyz/about/default.html

My personal email is howard@...

Howard


On 3/22/2020 4:33 PM, Gordon Gibby wrote:
A bit off topic!  I got asked to help build a ventilator for a low-cost application to save lives in COVID-19. A few brilliant engineers at the University of Florida are building a ventilator using cheap lawn sprinkler valves & pvc pipe  to direct compressed oxygen gas.   They needed a control system to manage the inspiratory and expiratory valves.

With What I have learned from Farhan and everyone here, I suggested the Arduino was the way to go; 

Last night and today I started building the little transistor drivers to handle the sprinkler valves. The only NPN power transistors I could find in the entire house were 2N3055s.  Then I wrote a simple program to read a potentiometer to adjust ventilatory rate, and for starters,  set the I to E ratio at the normal 1 to 2.  Using the potentiometer, the respiratory rate can be varied from 10 to 30.   They have simple spring mechanisms to create positive end expiratory pressure.  The prototype is working on my kitchen table, and I’m waiting for the mechanical engineer to drive over with the plumbing apparatus and the valves. 

Your building this open source, some of you really bright folks might want to jump in and help them with the software, if so email me and I will help get you into the group.  my part was just the simple transistor switches. 
 
Ashar— We may have a new product for you to build quickly.  And I’m sure you could make it a lot better


Gordon Gibby KX4Z




--
Jack, W8TEE

Re: Ventilator

Andy_501
 

good luck with efforts. Just found some scary news kind of resembles Nero fiddled while Rome burned though.

https://www.latimes.com/california/story/2020-03-20/coronavirus-county-doctors-containment-testing

On 2020-03-22 8:12 p.m., Gordon Gibby wrote:
Hi -- I forwarded that to Sem.   Thanks!!!
Gordon


On Sun, Mar 22, 2020 at 8:28 PM Howard Fidel <howard@...> wrote:

I am a medical device expert. If I can help in anyway, let me know. You can find my bio here:

http://w2hff.xyz/about/default.html

My personal email is howard@...

Howard


On 3/22/2020 4:33 PM, Gordon Gibby wrote:
A bit off topic!  I got asked to help build a ventilator for a low-cost application to save lives in COVID-19. A few brilliant engineers at the University of Florida are building a ventilator using cheap lawn sprinkler valves & pvc pipe  to direct compressed oxygen gas.   They needed a control system to manage the inspiratory and expiratory valves.

With What I have learned from Farhan and everyone here, I suggested the Arduino was the way to go; 

Last night and today I started building the little transistor drivers to handle the sprinkler valves. The only NPN power transistors I could find in the entire house were 2N3055s.  Then I wrote a simple program to read a potentiometer to adjust ventilatory rate, and for starters,  set the I to E ratio at the normal 1 to 2.  Using the potentiometer, the respiratory rate can be varied from 10 to 30.   They have simple spring mechanisms to create positive end expiratory pressure.  The prototype is working on my kitchen table, and I’m waiting for the mechanical engineer to drive over with the plumbing apparatus and the valves. 

Your building this open source, some of you really bright folks might want to jump in and help them with the software, if so email me and I will help get you into the group.  my part was just the simple transistor switches. 
 
Ashar— We may have a new product for you to build quickly.  And I’m sure you could make it a lot better


Gordon Gibby KX4Z



Re: Ventilator

Tom, wb6b
 

Best wishes on this important project. Here is a link with rough engineering specifications and GitHub links. This looks like the same project as being discussed here.

https://anest.ufl.edu/2020/03/17/cssalt-works-on-open-source-ventilator-design/