DIY Setpoint Controller

LakeLover · 21st May 2007, 13:28

Beutiful! Where did you have the board made? Can you tell us about the programming?

Andy T · 21st May 2007, 16:16

Quote: (Originally Posted by Dave Sutton)

Beautiful work! Nicer display than some of the so-called "factory" rigs. Well done! Really looks great.

I have a special project on my bench now, a rebreather for (get this), my Dachshund (who really dives, err... actually "walks on the bottom". Little legs make it hard to swim...) It's a fan-driven freeflow rebreather. I need a simple setpoint controller (to keep "Knirps" alive) and a HUD (so I can be his "Buddy" and monitor the loop). If you want to be able to brag that "Diver Dave's Dog Dives my Controller", you can be famous.... The little fellow has a hard time with open circuit gear (needs to be freeflow in the helmet, so wastes gas)....

Again, looks like a super system. Congratulations!

Dave

Hi Dave

It's very tempting - but also risky - I could become known as the bastard who drowned Dave's Dachshund.

Andy T · 21st May 2007, 16:26

Quote: (Originally Posted by canetoad)

Very nice. Your device looks like it has a lot of potential. Are those AA batteries in the picture? Was wondering if you have had the chance to guage battery life as yet? Please let us know how things develop.

At the moment it is running on 4 AA rechargable batteries (2500 mA Hrs each). I have run the system for a few hours with the solenoid firing every few seconds. I am not sure how long it will run on one charge. Battery life would depend to a large degree on how often the solenoid fires. The solenoid is rated at 0.6 watts and I am planning to use it in conjunction with a KISS valve, so battery life should be good. At the moment I have it programed so that the display backlight is on all the time - it draws 170 mA of which about 100 mA is used by the backlight.

**Dave Sutton** · 21st May 2007, 16:33

Quote: (Originally Posted by Andy T)

Hi Dave

It's very tempting - but also risky - I could become known as the bastard who drowned Dave's Dachshund.

Naah..... he's in a helmet, the worst he could do would be to pass out. I monitor the tail-wag rate and when it falls to zero WPS (wags per second) I poke him. The WPS rate is usually 5 or so....

Dave

Capt. Ray Goosen · 21st May 2007, 16:38

Yo, Drew nice one..leave am for sea, chat when I return, or durring if the colonel does not thow a fit, hehe. Oh,,need to get one of these for me, best I seen on this one..Take care.

Andy T · 21st May 2007, 16:51

Quote: (Originally Posted by LakeLover)

Beutiful! Where did you have the board made? Can you tell us about the programming?

The board is from Express PCB in the US.

The code is written in C. Much of the code is to control the graphics. Functionally the code does the following - on startup the user has 15 seconds to enter calibration or setup - otherwise the device puts itself in dive mode and pulls the last good calibration from the memory. Calibration is on air or oxygen, if the calibration passes the user can opt to save the data to memory. When in dive mode it samples the input from each of the three cells ten times and then updates the display with the average p02 values - the display updates a couple of times a second. Two setpoints can be defined by the user in setup and toggled in dive mode. The device has a simple two LED HUD - green = good and red = bad, these colors are also used a backlight for the P02 redaings on the display. Simple voting logic is implemented - if two of the cells say that the PO2 is below the setpoint then the solenoid fires. The time that the solenoid fires for is dependent on how far below setpoint the PO2 reading are. Once the solenoid has fired it is blocked from firing again for 6 seconds.

SteveL · 22nd May 2007, 09:07

Hi Andy - nice one - It looks like to board was custom made for the components??

Did you do the design on the express pcb software then have them build the custom board?? Whats with the stoned fish logo on the top

Regards,

SteveL

Andy T · 22nd May 2007, 10:18

Quote: (Originally Posted by SteveL)

Hi Andy - nice one - It looks like to board was custom made for the components??

Did you do the design on the express pcb software then have them build the custom board?? Whats with the stoned fish logo on the top

Regards,

SteveL

Yes - the board was designed using the Express PCB software. The design is emailed to them and they make the boards and post them back to you - the whole process takes about a week. Then its just a case of getting out the soldering iron - there are companies that will also solder on the components, but that works out pretty expensive if you are making small numbers.

The logo was just me having a bit of fun while designing the board. Since I was paying for a silk screen layer, I figured that I might as well include a logo - and I happen to like stone fish.

Capt. Ray Goosen · 3rd June 2007, 17:49

Yo, Drew wassup?

I got the plug, althou you know who is not speaking to me, he has his tit's in a twist at the mo, so best left alone to smoulder.

I will do the "Dunk" test tomorrow and hope to see you later, looks cool and I am sure she will be "Dry" , till next take care..

Capt. Ray Goosen · 5th June 2007, 20:17

Hi, Drew, got to do the "Dunk" test, and well, all is not well. I think the problem is with the type and form of the plugs "O" ring. I am sure that once we have changed out the "O" ring we will have better results..

Keep you posted Dude..Oh and yes the "Cyclone" has put a damper on my weekend plans..

till later..be safe out there.

21st May 2007, 13:28	#11 (permalink)
LakeLover New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: Northern New York Posts: 71	Re: DIY Setpoint Controller Beutiful! Where did you have the board made? Can you tell us about the programming?
(Offline)

21st May 2007, 16:16	#12 (permalink)
Andy T RBW Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: UAE Posts: 43	Re: DIY Setpoint Controller Quote: (Originally Posted by Dave Sutton) Beautiful work! Nicer display than some of the so-called "factory" rigs. Well done! Really looks great. I have a special project on my bench now, a rebreather for (get this), my Dachshund (who really dives, err... actually "walks on the bottom". Little legs make it hard to swim...) It's a fan-driven freeflow rebreather. I need a simple setpoint controller (to keep "Knirps" alive) and a HUD (so I can be his "Buddy" and monitor the loop). If you want to be able to brag that "Diver Dave's Dog Dives my Controller", you can be famous.... The little fellow has a hard time with open circuit gear (needs to be freeflow in the helmet, so wastes gas).... Again, looks like a super system. Congratulations! Dave Hi Dave It's very tempting - but also risky - I could become known as the bastard who drowned Dave's Dachshund.
(Offline)

21st May 2007, 16:26	#13 (permalink)
Andy T RBW Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: UAE Posts: 43	Re: DIY Setpoint Controller Quote: (Originally Posted by canetoad) Very nice. Your device looks like it has a lot of potential. Are those AA batteries in the picture? Was wondering if you have had the chance to guage battery life as yet? Please let us know how things develop. At the moment it is running on 4 AA rechargable batteries (2500 mA Hrs each). I have run the system for a few hours with the solenoid firing every few seconds. I am not sure how long it will run on one charge. Battery life would depend to a large degree on how often the solenoid fires. The solenoid is rated at 0.6 watts and I am planning to use it in conjunction with a KISS valve, so battery life should be good. At the moment I have it programed so that the display backlight is on all the time - it draws 170 mA of which about 100 mA is used by the backlight.
(Offline)

21st May 2007, 16:33	#14 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: DIY Setpoint Controller Quote: (Originally Posted by Andy T) Hi Dave It's very tempting - but also risky - I could become known as the bastard who drowned Dave's Dachshund. Naah..... he's in a helmet, the worst he could do would be to pass out. I monitor the tail-wag rate and when it falls to zero WPS (wags per second) I poke him. The WPS rate is usually 5 or so.... Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
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21st May 2007, 16:38	#15 (permalink)
Capt. Ray Goosen New Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: United Arab Emirates Posts: 50	Re: DIY Setpoint Controller Yo, Drew nice one..leave am for sea, chat when I return, or durring if the colonel does not thow a fit, hehe. Oh,,need to get one of these for me, best I seen on this one..Take care.
(Offline)

21st May 2007, 16:51	#16 (permalink)
Andy T RBW Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: UAE Posts: 43	Re: DIY Setpoint Controller Quote: (Originally Posted by LakeLover) Beutiful! Where did you have the board made? Can you tell us about the programming? The board is from Express PCB in the US. The code is written in C. Much of the code is to control the graphics. Functionally the code does the following - on startup the user has 15 seconds to enter calibration or setup - otherwise the device puts itself in dive mode and pulls the last good calibration from the memory. Calibration is on air or oxygen, if the calibration passes the user can opt to save the data to memory. When in dive mode it samples the input from each of the three cells ten times and then updates the display with the average p02 values - the display updates a couple of times a second. Two setpoints can be defined by the user in setup and toggled in dive mode. The device has a simple two LED HUD - green = good and red = bad, these colors are also used a backlight for the P02 redaings on the display. Simple voting logic is implemented - if two of the cells say that the PO2 is below the setpoint then the solenoid fires. The time that the solenoid fires for is dependent on how far below setpoint the PO2 reading are. Once the solenoid has fired it is blocked from firing again for 6 seconds.
(Offline)

22nd May 2007, 09:07	#17 (permalink)
SteveL RBW Member Current Rebreather/s: MK 15.X Other Rebreather/s: Inspiration Classic Join Date: Nov 2005 Location: Sydney Australia Posts: 224	Re: DIY Setpoint Controller Hi Andy - nice one - It looks like to board was custom made for the components?? Did you do the design on the express pcb software then have them build the custom board?? Whats with the stoned fish logo on the top Regards, SteveL
(Offline)

22nd May 2007, 10:18	#18 (permalink)
Andy T RBW Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: UAE Posts: 43	Re: DIY Setpoint Controller Quote: (Originally Posted by SteveL) Hi Andy - nice one - It looks like to board was custom made for the components?? Did you do the design on the express pcb software then have them build the custom board?? Whats with the stoned fish logo on the top Regards, SteveL Yes - the board was designed using the Express PCB software. The design is emailed to them and they make the boards and post them back to you - the whole process takes about a week. Then its just a case of getting out the soldering iron - there are companies that will also solder on the components, but that works out pretty expensive if you are making small numbers. The logo was just me having a bit of fun while designing the board. Since I was paying for a silk screen layer, I figured that I might as well include a logo - and I happen to like stone fish.
(Offline)

3rd June 2007, 17:49	#19 (permalink)
Capt. Ray Goosen New Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: United Arab Emirates Posts: 50	Re: DIY Setpoint Controller Yo, Drew wassup? I got the plug, althou you know who is not speaking to me, he has his tit's in a twist at the mo, so best left alone to smoulder. I will do the "Dunk" test tomorrow and hope to see you later, looks cool and I am sure she will be "Dry" , till next take care..
(Offline)

5th June 2007, 20:17	#20 (permalink)
Capt. Ray Goosen New Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: United Arab Emirates Posts: 50	Re: DIY Setpoint Controller Hi, Drew, got to do the "Dunk" test, and well, all is not well. I think the problem is with the type and form of the plugs "O" ring. I am sure that once we have changed out the "O" ring we will have better results.. Keep you posted Dude..Oh and yes the "Cyclone" has put a damper on my weekend plans.. till later..be safe out there.
(Offline)

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