- What is the best (as well as most inexpensive) way to power it?
- What is the best way to store a recorded altitude?
Trinket Altimeter
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
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- Posts: 13
- Joined: Mon May 13, 2013 11:07 pm
Trinket Altimeter
I'm trying to make an altimeter for a model rocket using a trinket and a barometric pressure sensor (it has to be real small.) I have two questions.
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Trinket Altimeter
A model rocket will make short flights, so you probably don't have to worry about battery life.
LiPo cells have the best energy density on the consumer market, and these are pretty small:
https://www.adafruit.com/products/1570 - 100mAh
https://www.adafruit.com/products/1317 - 150mAh
All our pressure/altitude sensors are small:
https://www.adafruit.com/categories/114
Whichever one you choose, you'll need some kind of microcontroller to run it, and for sheer lack of size, it's hard to beat the Teensy:
https://www.adafruit.com/products/199
That uses the same microcontroller as the Arduino Leonardo or Micro, so it's generally compatible with Arduino code.
For storage, it's a toss-up..
The WS25Q80BV Flash chip is small, but you have to read and write the data directly. You'd need a separate sketch to pull the data out of the chip and move it to a computer:
https://www.adafruit.com/products/1564
A Micro-SD card is also small, though our breakout adds some size to it. The advantage is that you can pull the card out of the connector and plug it directly into a computer:
https://www.adafruit.com/products/254
LiPo cells have the best energy density on the consumer market, and these are pretty small:
https://www.adafruit.com/products/1570 - 100mAh
https://www.adafruit.com/products/1317 - 150mAh
All our pressure/altitude sensors are small:
https://www.adafruit.com/categories/114
Whichever one you choose, you'll need some kind of microcontroller to run it, and for sheer lack of size, it's hard to beat the Teensy:
https://www.adafruit.com/products/199
That uses the same microcontroller as the Arduino Leonardo or Micro, so it's generally compatible with Arduino code.
For storage, it's a toss-up..
The WS25Q80BV Flash chip is small, but you have to read and write the data directly. You'd need a separate sketch to pull the data out of the chip and move it to a computer:
https://www.adafruit.com/products/1564
A Micro-SD card is also small, though our breakout adds some size to it. The advantage is that you can pull the card out of the connector and plug it directly into a computer:
https://www.adafruit.com/products/254
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- Posts: 13
- Joined: Mon May 13, 2013 11:07 pm
Re: Trinket Altimeter
I can't use an Adafruit Trinket? I can power a 3.3v one with one of these, right? Is there a definitive tutorial for the tiny flash library?
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Trinket Altimeter
The Trinket can talk to the Flash chip (barely), but doesn't have enough memory to work with an SD card.
The only code we have for the Flash chip is here: https://github.com/adafruit/Adafruit_TinyFlash, and it has an 'advanced hacking' challenge rating. One 256-byte page of Flash is half the Trinket's total SRAM, so almost everything is written in low-level code.
The only code we have for the Flash chip is here: https://github.com/adafruit/Adafruit_TinyFlash, and it has an 'advanced hacking' challenge rating. One 256-byte page of Flash is half the Trinket's total SRAM, so almost everything is written in low-level code.
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- Posts: 13
- Joined: Mon May 13, 2013 11:07 pm
Re: Trinket Altimeter
Okay, I have an Adafruit OLED screen laying around that I'm not using. I think I'll use that to display the highest altitude reached. Using a barometric sensor and an oled together won't be a problem right?
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Trinket Altimeter
The OLED and sensor shouldn't interfere with each other, but a Trinket doesn't have enough memory to run an OLED.
The smallest OLED we have has a 128x32 display area. The display buffer for that would consume 512 bytes of RAM, and a Trinket only has 512 bytes of RAM. There wouldn't be any memory left for anything else.
The smallest OLED we have has a 128x32 display area. The display buffer for that would consume 512 bytes of RAM, and a Trinket only has 512 bytes of RAM. There wouldn't be any memory left for anything else.
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- Posts: 13
- Joined: Mon May 13, 2013 11:07 pm
Re: Trinket Altimeter
I'm postponing this project in favor of a different one for now. It's windy this season anyway. Thanks for all your help.
- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Trinket Altimeter
Fair enough.
Putting a project on hold is always a good excuse to look for other small projects that use bits of the same hardware, or just to tinker with things when you have a few minutes. You can pick up a lot of background knowledge from a batch of 15-minute "let's see what this does" experiments.
Putting a project on hold is always a good excuse to look for other small projects that use bits of the same hardware, or just to tinker with things when you have a few minutes. You can pick up a lot of background knowledge from a batch of 15-minute "let's see what this does" experiments.
Please be positive and constructive with your questions and comments.