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by FiddlerJones
Wed May 18, 2016 9:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Re: Two devices connected to a single UART

Try waiting a bit longer between tries, I mean an unnecessary long amount of time, and see if you can get the data in a correct format. If not, maybe you don't have a fix? Have you tried testing on the outside? My GPS module was able to find the fix only after about 30 seconds outside, when I was te...
by FiddlerJones
Mon May 16, 2016 4:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Re: Two devices connected to a single UART

If you read my poorly written code above, you can find what I used a solution to avoid data corruption. You cannot. Unless you wait a bit before reopening the UART port, the time to wait is not constant though, so you cannot know if you'll end up with correct data or not, unless waiting a "worst-cas...
by FiddlerJones
Wed Mar 05, 2014 12:07 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Re: Two devices connected to a single UART

Yes of course I killed those processes. Anyway, here's a quick update of what I've done: - Connected the GPS to the 5V pin. Did not work, it isn't a power supply problem. - Switched to 9600 baud right after the transmission and add some extra sleep time. It went a little better, but the software cra...
by FiddlerJones
Tue Mar 04, 2014 2:50 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Re: Two devices connected to a single UART

I succeeded transmitting the data from a generic GPIO pin with the pigpio library. I had some timing issues with the baudrate set to 50, or 75, or 100, or 110, or 150, or 200 (I couldn't even hear the RTTY on the radio). Fortunately at 300 baud worked great and I was able to decode it with Fldigi. I...
by FiddlerJones
Mon Mar 03, 2014 3:07 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Re: Two devices connected to a single UART

The garbled characters are in raspbian itself! Anyway, as I said, the radio and the GPS works great individually, so the GPS works fine at 3.3V, it has an internal linear-drop out for when it's fed with higher voltages. It even has a clean 3.3V output. The GPS draws about 20mA and so does the Radio....
by FiddlerJones
Sun Mar 02, 2014 9:26 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Re: Two devices connected to a single UART

Ok, in order: All GND pins are connected together. I tried to open the port once and change the baudrate without closing it. Didn't work. I tried "flushing" in every way and moment possible. Didn't work. I tried setting the same baudrate for the two devices (9600). I know, the radio signal would hav...
by FiddlerJones
Sat Mar 01, 2014 1:26 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Two devices connected to a single UART
Replies: 27
Views: 9706

Two devices connected to a single UART

Hi! As I explained in some of my previous cry for help posts, my project is an high altitude balloon flight. I connected the BMP085 sensor via I²C, the Adafruit Ultimate GPS via USB with an USB to UART bridge (CP2102, borrowed from a friend), and the NTX2 radio telemetry via UART. Now, I'd like to c...
by FiddlerJones
Mon Jan 20, 2014 4:52 pm
Forum: Camera board
Topic: Flashing band across video
Replies: 41
Views: 16950

Re: Flashing band across video

I had that problem too. I cut off the Linear Drop Out on the board and replaced it with a switching regulator, feeding the raspberry only with 3.3V (combining the 5V and 3.3V). At first I used the micro usb port to supply the current, and I had those band both on videos and photos. Swapping the micr...
by FiddlerJones
Mon Dec 09, 2013 1:15 am
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Re: Running Raspberry on 3.3 V

I'd like to try running my PI from AA or AAA batteries using a regulator but I don't want to desolder the existing LDO. It sounds like you are saying this is possible. Can you recommend component codes for the 3.3 regulator? Then the regulator is connected to the battery holder and +3.3 and +5v + g...
by FiddlerJones
Sat Nov 23, 2013 8:56 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Re: Running Raspberry on 3.3 V

I did the test again, no keyboard, no mouse, locked GPS (thanks for the heads up), video outputs off, and I've optimized the software to turn off the temperature/pressure sensor between the data collection and to use the camera taking video only where I need (for a final ~ 3 min videoclip). So I've ...
by FiddlerJones
Sun Nov 17, 2013 4:38 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Re: Running Raspberry on 3.3 V

If your model A Pi is drawing 400mA, something is wrong. Perhaps a bad DMM. It should be around 115mA. I tried a few things to reduce that, and the only noticeable power reduction was to switch off the video output. On top of that, you'll need around 80mA for the radio and GPS, so total for the tra...
by FiddlerJones
Fri Nov 15, 2013 12:57 am
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Re: Running Raspberry on 3.3 V

By far and away the best option for stopping any overheating in a weather balloon payload is to not generate the heat in the first place, and for a Pi tracker that means using a model A. Average consumption will then be around the 200mA mark for the entire tracker, except for during any video recor...
by FiddlerJones
Thu Nov 07, 2013 4:05 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Re: Running Raspberry on 3.3 V

With my configuration it should run for almost 7 hour. (6 AAA, 85% efficiency, 400mA used by the RPi) The current measured by the multimeter was about 300mA while powering the GPS and the pressure/temperature sensors, and 650mA with the Camera Board taking Full HD video or photo, so, considering tak...
by FiddlerJones
Wed Nov 06, 2013 11:22 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Re: Running Raspberry on 3.3 V

For what reason do you want to back feed 3.3v to The 3.3v output pin. What is your project ,for doing this connection ? Knowing this might help a lot BoyOh I need the longest run time with the lightest battery option, and the LDO on the raspberry is an enormus waste of energy, so I was thinking abo...
by FiddlerJones
Mon Oct 28, 2013 11:26 pm
Forum: Advanced users
Topic: Running Raspberry on 3.3 V
Replies: 33
Views: 22223

Running Raspberry on 3.3 V

I know that is possible to power the raspberry via GPIO, connecting 5V to pin 2 and GND to pin 6. Here's my question now: is it possible to power the raspberry connecting 3.3V to pin 1 and GND to pin 6?
Of course I won't be use anything that runs on 5V!
by FiddlerJones
Sun Sep 22, 2013 8:37 pm
Forum: Automation, sensing and robotics
Topic: Absolute Pressure Transducer / Altimeter
Replies: 3
Views: 4071

Re: Absolute Pressure Transducer / Altimeter

Since the pressure analysis in the stratosphere is too much of a problem, I decided to use GPS data to track the altitude. I chose this GPS shield: http://www.adafruit.com/products/746 even though the description claim 27km to be the max reachable altitude , the adafruit support team assured me that...
by FiddlerJones
Wed Sep 18, 2013 8:58 pm
Forum: Automation, sensing and robotics
Topic: Absolute Pressure Transducer / Altimeter
Replies: 3
Views: 4071

Absolute Pressure Transducer / Altimeter

Hi! I'm thinking to send a balloon into near space, trying to get some picture, video and data. The raspberry pi will have the control of everything. My problem is: i can't find a way to measure the altitude reached by the balloon. I thought of measuring pressure and than calculate the altitude with...

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