Weather sensor using jack


koal01
 

Hi 
I’d like to add a sensor to control both TCF on a focuser and a dew heater. The DS18b20 is interesting as i could connect it to the jack on a MAXPCB 3.6. The link to « one wire de vice » in the wiki is broken so i’m not able to check if this device is adapted to this use. 

Thak you for tour help


koal01
 

I have found severall bmp180 in my drawer, not sure this component is comptable with onstepX…


hitosi sato
 

Hi
I am also going to use DS1820 for Dew heater.
I have not received the parts yet, so I am only trying to compile it, but there seems to be no particular problem with OnStepX.
If you want to get the s/n of the DS18B20, you need to look it up with DEBUG VERBOSE.
I looked it up by searching the message.

https://onstep.groups.io/g/main/search?p=recentpostdate%2Fsticky%2C%2C%2C20%2C2%2C0%2C0&q=DS1820

Hitoshi


Howard Dutton
 

On Wed, Nov 9, 2022 at 03:23 PM, hitosi sato wrote:
I am also going to use DS1820 for Dew heater.
I have not received the parts yet, so I am only trying to compile it, but there seems to be no particular problem with OnStepX.
If you want to get the s/n of the DS18B20, you need to look it up with DEBUG VERBOSE.
I looked it up by searching the message.
Covered in the OnStepX Wiki:
Auxiliary Features, control switches, dew-heaters, etc.
... and within that page this link
About OneWire Devices.


koal01
 

For dew heater i thinq there should not be an issue with this component, my question was more on using it to control TCF on a focuser.

Thank you


koal01
 
Edited

Howard the  target of the About onwire devices link dioes not work for me


Howard Dutton
 

Sorry those still pointed into the developer subgroup, guess you are not a member.

I moved the pages, should be fixed now.

  • FOCUSER_TEMPERATURE
    • Default Value: OFF
    • Other Values: OFF, THERMISTOR, THERMISTOR2, n (where n is the ds18b20 serial number.)
    • Notes:
      • Provides the focuser temperature which is used for TCF (Temperature Compensated Focusing.)
      • In the absence of an device here the system falls back to the WEATHER device to get the temperature for TCF.
      • If using an DS18B20 read About One-Wire Devices.
      • If using an Thermistor read About Thermistor Devices.


koal01
 

Right, so i was in the wrong way according to the wiki.
Can you please correct if i'm still wrong, if i want to control TCF on the focuser and a dew heater to control the temperature on the scope i need to plug 2 onewire sensors (ds18B20) for instance in AUX3 and AUX4.
Each one has to be dedicated to one purpose controlling the device through the resistances i can see on the PCB
Theres is also a 3 pin ENC PULL mention on the PCB, it has to be wired i suppose.

Thank you 


Howard Dutton
 

On Thu, Nov 10, 2022 at 02:36 AM, koal01 wrote:
Can you please correct if i'm still wrong, if i want to control TCF on the focuser and a dew heater to control the temperature on the scope i need to plug 2 onewire sensors (ds18B20) for instance in AUX3 and AUX4.
Its more complicated than that, OnStepX will fall-back to other temperature sources (BME280 for instance) in lieu of having point temperature associated with the device (Thermistors or DS18B20.)

Each one has to be dedicated to one purpose controlling the device through the resistances i can see on the PCB
I don't understand this statement but it sounds incorrect.

Theres is also a 3 pin ENC PULL mention on the PCB, it has to be wired i suppose.
Not related to this.


Howard Dutton
 

On Thu, Nov 10, 2022 at 02:36 AM, koal01 wrote:
dew heater to control the temperature on the scope
There are two modes of dew-heater control both require a BME280 or equivalent source of Temp and Humidity.

If you have another point temperature device measuring the dew heater surface the control can be more exact to avoid unnecessary excess heating.  Useful for a newtonian secondary mirror for example.

Without the other point temperature device you can still have rough control where more heat is applied as the air temperature approaches dew-point.


koal01
 

A second try...

OnstepX uses a source temperature through #define WEATHER in which we can wire a BME280 or BMP280 ... and if we have 2 different devices to control (TCF and Dew hetater) we need to use 3 auxiliary outputs, AUX3, AUX4 and AUX5 ? In this case it would be one auxiliary input for the BMP280 and two other auxiliary features with ds18B20 onewire sensors, the 1st one connected to AUX4 for TCF and the second one on AUX5 for Dew heater....


Howard Dutton
 

On Thu, Nov 10, 2022 at 03:32 AM, koal01 wrote:
OnstepX uses a source temperature through #define WEATHER in which we can wire a BME280 or BMP280 ... and if we have 2 different devices to control (TCF and Dew hetater) we need to use 3 auxiliary outputs, AUX3, AUX4 and AUX5 ? In this case it would be one auxiliary input for the BMP280 and two other auxiliary features with ds18B20 onewire sensors, the 1st one connected to AUX4 for TCF and the second one on AUX5 for Dew heater....
The BME280 gets attached to I2C (SDA/SCL) and there needs to be one other pin devoted to 1-Wire (both DS18B20's are on that.)

You then need an output pin to control the dew heater power.


Howard Dutton
 

On Thu, Nov 10, 2022 at 03:32 AM, koal01 wrote:
or BMP280
You need humidity for dew-point, so the BMP will not work.


Howard Dutton
 
Edited

For dew-heaters (etc.) and the Max series controllers there might one day be specific hardware for that, but it's really not ready yet.

This concept uses 1-Wire only (two DS2413 1-Wire GPIOs for switching the heaters, etc.) and slides into the same aluminum case the MiniPCB2 uses:


koal01
 

Nice hardware that i will certainly use in the future, it's like a small passive OCS no ?

Concerning the questions it is clear  now, sorry i'm always confusing between BMP and BME280, the second sensor is covering humidity not the first one.
About TCF i also understand that there's no wire needed except the BME as an input sending the data to OnstepX wich send instructions to focus in or out
The Dew heater needs one ds18B20 as an auxiliary input and an auxiliary output to control the device heating.
I hope there won't be another try ...LOL


Howard Dutton
 

For 1-Wire and the Max series controllers I like the concept of using the stereo mini jack on the back for 1-Wire as that puts all signals needed on an convenient off-the-shelf cable.

Specifically the 3.5mm stereo-mini has contacts for Gnd, Aux8, and Aux7.  I use Aux8 for the 1-Wire signal and re-purpose the Aux7 contact for 3.3V.

To obtain the 3.3V you can use an Auxiliary feature to set the Aux7 pin of the microcontroller so it defaults to logic HIGH (3.3V)  The MaxESP3 and 4 controllers can instead be jumpered to disconnect Aux7 and instead route 3.3V to the relevant contact.

Naturally some re-thinking things might be required for the limit sense and/or reticle.


koal01
 

That is exactly what i wanted to do from the beginning but i was confused with the mention on the PCB dedicating AUX7 and 8 for the reticle and limit sense.
For humidity, temperature; etc... i could use my OCS but not sure this feature is implemented in Onstep !
I'll use the DB15 for the BME

Thank you Howard for these precious explanations 


koal01
 

Actually the dew heater needs 12 V, i don't know if an Auxiliary output can supply to this level or if we need to add a switch with an external 12v supply.


Howard Dutton
 

I would use a separate 12VDC supply.


koal01
 

and the specific hardware you shew for dew heaters, etc... ,  when will it be avalaible ?