BMP180 as altimeter for HPR?

[Anuk Rathnayake]

so I'm building a rocket that will go 4900ft and ~250m/s (openrocketsimulation) and may use a bmp180 to find apogee in order to set of pyro channels for parachutes. My question is would the bmp be able to cope with the sudden pressure changes and speed. Please let me know what code I should write as I know that the pressure reading has an uncertainty of around +-40cm.

 

[Spacedog49Krell]

Bosch classifies the BMP180 as an obsolete sensor that is no longer manufactured by Bosch. I have used the BMP180 in altimeter projects, but I prefer the BMP280 which has better altitude resolution. The BMP180 is not limited in velocity pressure change or altitudes below 30,000 feet. As for code, you have not provided details of your application other than a set of multiple(?) pyro channels for parachute deployment. Is this to be for apogee only or dual deployment?

 

[Anuk Rathnayake]

Bosch classifies the BMP180 as an obsolete sensor that is no longer manufactured by Bosch. I have used the BMP180 in altimeter projects, but I prefer the BMP280 which has better altitude resolution. The BMP180 is not limited in velocity pressure change or altitudes below 30,000 feet. As for code, you have not provided details of your application other than a set of multiple(?) pyro channels for parachute deployment. Is this to be for apogee only or dual deployment?

Thanks for the info. It will be only to detect apogee. I will be able to write the rest of the code but I will need help with finding apogee. I am using an Arduino nano and the Arduino ide.

 

[waltr]

For simply detecting Apogee it will work IF your code is written correctly. This includes no False apogee detection.

Please fly this with logging only and use a Known device to fire ejection and deploy chutes.
Then post flight analyize the data and how well your code determined apogee.

 

[John Beans]

Yes, Jolly Logic used the BMP180 for many years in our products. Using it is a bit of a pain compared to more modern sensors as there are a number of parameters you have to download and use in your calculations, but it is quite accurate.

 

[cerving]

We used the BMP085/BMP180 for about 3 years until it went EOL, it works fine for both apogee and real-time altitude detection. I would strongly advise against using a 10 year-old part that's been EOL for 8 years, however.

 

[Spacedog49Krell]

Attached is an IDE file that should work with your Nano altimeter. I don't have a BMP180 to test, it did work with the BMP280. This code is based on the Pro Mini Altimeter from Lonnie Utah. It is well documented with notes.

I did find two Ebay sellers of BMP280 4 pin pcb's that are direct replacements for the BMP180 4 pin pcb's. You can upgrade your flight computer should you find the need. The BMP280 does have built-in temperature and pressure oversampling to smooth the altimeter readings. When tested with the BMP280 it recorded at 70Hz to the SD card.