HUD Project Update

English Mark

Hey Darlene,
Have you considered laminating your housings out of fiberglass with polyester or epoxy resin ? they can be as strong as you like and plastic containers (even a margarine tub) can be found that is the ideal size for what you need to house. include a flange for the face plate and you can have it machined for an o ring. Being as your resources for materials are limited it might be away to go. By the way , love the press. pot
English mark

Xandertendolle

Darlene, your project really looks nice. You don't use the decimal point in your'e ppo2 reading. I wrote the next routine for it. Maby somebody can use it.

Would you mind posting the routines you wrote?

Kind regards,

Xander


' {$STAMP BS2e}
' {$PBASIC 2.5}
Reset: 'Reset display op pin 0
HIGH 0
PAUSE 100
SEROUT 0, 32, [$12, $16, $0c] ' clear display

'______________________________________________DEC LARATIES
tel1 VAR Nib
ppo1 VAR Word(4)
ppo2 VAR Word(4)
ppo3 VAR Word(4)

'______________________________________________MAI N PROGRAM
Main:
DEBUGIN DEC3 ppo1(0) 'manualy give in the ppo2 reading, just for testing
DEBUGIN DEC3 ppo2(0) 'manualy give in the ppo2 reading, just for testing
DEBUGIN DEC3 ppo3(0) 'manualy give in the ppo2 reading, just for testing
GOSUB ppo_display

END
'_________________________________________________ _____SUBrountines
ppo_display:
FOR tel1 = 1 TO 3 'writes the ppo2 reading in an array.
ppo1(tel1)= ppo1(0) DIG (tel1-1)
ppo2(tel1)= ppo2(0) DIG (tel1-1)
ppo3(tel1)= ppo3(0) DIG (tel1-1)
NEXT 'writes the reading to LCD screen
SEROUT 0, 32, [$94, DEC ppo1(3), ".", DEC ppo1(2), DEC ppo1(1)]
SEROUT 0, 32, [$9a, DEC ppo2(3), ".", DEC ppo2(2), DEC ppo2(1)]
SEROUT 0, 32, [$a0, DEC ppo3(3), ".", DEC ppo3(2), DEC ppo3(1)]
GOTO main

Scuba_Vixen

There's no decimal point in the PO2 reading in the 2X16 LCD display because the BS2 only does integer math. Also, it's just easier to have it display everything as a 3 digit decimal base number, so there's just a leading zero for PO2 less then 1.00 ....

It's all really kind of moot though, as that display is just for calibration, and maybe for a buddy to be able to see. It's not located where the diver has visual access to it.

Take a look at this thread for the latest update and pictures of the finished unit; .. It now has electronic setpoint control capability.

http://www.rebreatherworld.com/home-...in-builup.html



Darlene

whoizrob

Hey Darlene,

Been on vacation for a bit and haven't kept up with RBW but I just read the tail end of this thread where you mention not using decimals on your display with a BS2 board. I am also playing with a Pbasic setup for my meters and recall reading that you CAN set up the code to display decimals should you so desire. If that is the case let me know and I'll try and dig up my references. Good luck!

Rob

Scuba_Vixen

You can specify any character to any location on the display you want to, that's correct.

Xander's program shows a way to write the PO2 with a decimal point by using code to add it to the string of digits. I was already having to trim stuff 'cuz I was getting "eprom full" errors, so I didn't see the decimal point as worth trying to make eprom room for.

What I was otherwise referring to was that if you have code that divides a value by 3 (for example), it will only display the result in integers. If the value is a factor of 3, that's no problem. If the value is 30, the result is 10. If the value is 31 or 32, the result displayed is still 10. It can't display 10.3 or 10.6 as a function of the division command. ...

The way I set mine up is that the A/D result for a PO2 of 1.00 is 2500. (which represents 2.500 volts input to the adc) ..... To get the 3 digit, "100" reading on the display, the code divides the A/D result by 25.

You can see the 4 digit number below the PO2 reading is the raw A/D result number. The HUD controller uses the A/D result of each cell to determine which led(s) to lite, and the O2 control averages the A/D results from all 3 cells to control the solenoid.

Displaying the PO2 in the normal manner was just a matter of dividing the A/D result by 25.
What I did to make it easy and save some code lines, was to use DEC3 with a start location to display the PO2 for each cell. That way if the PO2 is less than 1.00, a leading zero appears, The PO2 is always displayed in 3 digits and there's always 2 decimal places of resolution to the PO2 readout. Adding the decimal point would require using 4 locations, as opposed to 3 for each cell's reading, and would crowd the space needed for the "D" & "E" for Disabled & Enabled for the O2 injection capability.

Keep in mind that that display is not visible to the diver during the dive, it's really only needed for predive calibration. That display is just a digital readout from the board that controls the HUD and O2 solenoid driver board.

The handset has 3 displays (3 1/2 digit lcds) that do have the decimal point enabled, and that is what the diver actually looks at. The handset display module shares the same 3 cells with the HUD, but has it's own driver board, calibration, and voltage regulation circuit.


Hope this makes it easier to follow,



Darlene