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by TheRayTracer
Sat Jan 28, 2017 10:08 pm
Forum: Other projects
Topic: Adafruit Ultimate GPS pulling enable pin high
Replies: 5
Views: 926

Re: Adafruit Ultimate GPS pulling enable pin high

Thanks guys. I think I've got it in combination with the following reference: https://learn.sparkfun.com/tutorials/pull-up-resistors
by TheRayTracer
Fri Jan 27, 2017 9:08 pm
Forum: Other projects
Topic: Adafruit Ultimate GPS pulling enable pin high
Replies: 5
Views: 926

Re: Adafruit Ultimate GPS pulling enable pin high

Thanks for looking up the schematic. I too now see the presence of the R2 resister. If you want to prove this just use a multi meter set to volts and connect it between EN and GND while the board is powered. Shouldn't I set the multi meter to measure Ohms and connect it between EN and GND to measure...
by TheRayTracer
Fri Jan 27, 2017 1:13 pm
Forum: Other projects
Topic: Adafruit Ultimate GPS pulling enable pin high
Replies: 5
Views: 926

Adafruit Ultimate GPS pulling enable pin high

Hi, I am using Adafruit's Ultimate GPS unit. All is going great, and with Vcc, Gnd, Tx, and Rx pins setup the Rasp Pi and GPS unit are talking to each other. Moving on from an early prototype stage, I would like to make use of other pins. These would include the EN and FIX pins. Focusing on the EN p...
by TheRayTracer
Mon May 09, 2016 10:49 am
Forum: Automation, sensing and robotics
Topic: How do we get the ADXL345 to output angles?
Replies: 5
Views: 1495

Re: How do we get the ADXL345 to output angles?

but have come to find that the values that the ADXL produces are not angles but some sort of gravity measuements - lol. Yes, the ADXL class of devices measure acceleration (and thus gravity). I would highly recommend that you read the datasheet: http://www.analog.com/media/en/technical-documentatio...
by TheRayTracer
Tue Apr 19, 2016 2:32 am
Forum: General discussion
Topic: LoRa parts with RPi
Replies: 1
Views: 1764

LoRa parts with RPi

I'm surveying LoRa devices and assessing their suitbility for use with RPi. Adafruit have recently released a series of devices that are a board with a RFM9x part attached, both 433MHz and 900MHz. Link: https://www.adafruit.com/product/3073 There is also a dedicated RPi expansion board with the exac...
by TheRayTracer
Sun Mar 20, 2016 12:27 am
Forum: Other projects
Topic: Measurement Distance from start point to RC-car
Replies: 13
Views: 1944

Re: Measurement Distance from start point to RC-car

Another possibility might be to measure the rotation of the wheels. In an ideal situation, there would be no slippage between the wheels and the ground. That would then allow us to know how far the vehicle has traveled by determining how much each wheel has turned. Using some trigonometry and maybe...
by TheRayTracer
Sat Mar 19, 2016 11:34 pm
Forum: Other projects
Topic: Measurement Distance from start point to RC-car
Replies: 13
Views: 1944

Re: Measurement Distance from start point to RC-car

Do you really only want to measure distance, or do you need position? What are you trying to achieve? How about painting / laying down a mat of coloured zones on the floor? A simple colour sensor could measure what zone the car was in. A camera sensor could work, either overhead to ID the car (see ...
by TheRayTracer
Sat Mar 19, 2016 6:48 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Sub 1" color display
Replies: 9
Views: 1459

Re: Sub 1" color display

Congratulations on receiving your SSD1331 device. :) Believe me that seeing a few random lines and dots is better than starring at a black screen trying to figure out what may or may not be wrong. :) There really isn't a SSD1331 "driver" to "install". If you are referring to my link in my post above...
by TheRayTracer
Fri Mar 18, 2016 3:21 am
Forum: Other projects
Topic: Measurement Distance from start point to RC-car
Replies: 13
Views: 1944

Re: Measurement Distance from start point to RC-car

No worries. In the future to avoid wasting time and a few rounds of correspondents, remember to state your question/problem as accurately as possible. Your RC-car test area has grown from 72'x72' inches to 2x2m to now something larger, and accuracy is no longer important. Yes, use Bluetooth if your ...
by TheRayTracer
Thu Mar 17, 2016 10:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Custom time interval between SPI characters
Replies: 3
Views: 613

Re: Custom time interval between SPI characters

According to the documentation: http://tightdev.net/SpiDev_Doc.pdf There is a subtle difference between the use of xfer() and xfer2(). xfer() - "CS will be released and reactivated between blocks" and xfer2() - "CS will be held active between blocks". In your case I would recommend to use xfer2(). I...
by TheRayTracer
Thu Mar 17, 2016 9:18 pm
Forum: Other projects
Topic: Measurement Distance from start point to RC-car
Replies: 13
Views: 1944

Re: Measurement Distance from start point to RC-car

The following is a serious suggestion. Since your 2x2m area shall not have obstacles, is it possible to attach a string line from your starting point to your RC-car? The starting point will always ensure that the string is tight (ie. no slack). Then you only have to measure the string. I'm sure ther...
by TheRayTracer
Wed Mar 16, 2016 10:55 pm
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

Let's start at the beginning. How have you wired up the device to your RPi? Device Vcc to pin 1 (3V), Device Gnd to pin 6? Device I2C to pins 3 and 5? Device INT 1 and 2 to which GPIO pins? I dont how do in python to read the interruption You are missing the understanding of using interrupts. Please...
by TheRayTracer
Wed Mar 16, 2016 9:49 pm
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

With an interrupt setup you don't need your loop logic. When your interrupt pin goes active, just open your parachute. This will be much more reliable. It could be deadly if your interrupt goes active while your RPi is sleeping for 0.1 seconds inside your loop. That's about a full 1 meter of free fa...
by TheRayTracer
Wed Mar 16, 2016 9:40 pm
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

I would suggest starting to read the device ID to ensure that everything is working and ok. See: 0x0D: WHO_AM_I Device ID Register in the datasheet. Then slowly build up your functionality. Please reread this. You are just diving in and excepting it to work. What value do you receive when you read ...
by TheRayTracer
Tue Mar 15, 2016 4:51 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More than 2 SPI slaves
Replies: 19
Views: 6649

Re: More than 2 SPI slaves

You may successfully use more that two SPI style devices. You may simply use any free GPIO pin on the RPi to manually toggle the CS for the slave device. This may not work for all SPI devices, such as those that require the CS to go inactive between each byte of a transmission, but most devices woul...
by TheRayTracer
Mon Mar 07, 2016 9:35 pm
Forum: Other projects
Topic: Location tracking indoor
Replies: 3
Views: 2336

Re: Location tracking indoor

I'm sure you are going to be another one-post-wonder, but anyway... GPS was only designed to work outdoors. I'm not clicking your link for a non existent product. Even if you used an indoor GPS / IPS, your board is only 72" x 72". GPS is only accurate down to 3 meters. You would detect no movement o...
by TheRayTracer
Mon Mar 07, 2016 3:55 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Using iPad Air as a RPi monitor?
Replies: 3
Views: 2926

Re: Using iPad Air as a RPi monitor?

Connect your RPi to your WiFi network, or use an Ethernet cable to connect to your router. Then you can log into your RPi using the command line from a standard PC (or iPad) using a client such as Putty.
by TheRayTracer
Sun Mar 06, 2016 9:20 pm
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

Section 4 of the datasheet outlines the setup registers for free fall configuration. I would also highly recommend that you read section 5 and configure a interrupt when free fall is detected. When using an interrupt you will not need any loop logic, and you can just wait for the interrupt pin to go...
by TheRayTracer
Sat Mar 05, 2016 10:11 am
Forum: Other projects
Topic: Raspberry as graphic calculator?
Replies: 4
Views: 959

Re: Raspberry as graphic calculator?

Considering that the TI-83 (released in 1996) was one of the more popular in the range, it's CPU was only 6 - 15MHz and only 32kB of RAM. ANY RPi could do what a TI could calculate. In this case it would be more about the software to "handle" the "algebra", than worrying about the hardware. Any RPi ...
by TheRayTracer
Fri Mar 04, 2016 8:21 pm
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

The device, like most devices, requires setup steps to get the device into the right mode. Where have you set the range? I would suggest starting to read the device ID to ensure that everything is working and ok. See: 0x0D: WHO_AM_I Device ID Register in the datasheet. Then slowly build up your func...
by TheRayTracer
Fri Mar 04, 2016 8:30 am
Forum: Other projects
Topic: VoxCube – 8x8x8 RGB LED Cube for the Raspberry Pi
Replies: 4
Views: 2095

Re: VoxCube – 8x8x8 RGB LED Cube for the Raspberry Pi

Could you make a Kit only reward that contains the PCB and other parts unassembled? It will not knock a lot off the price but it will help a little. And maybe a reward that only contains the PCB and the blueprints to make your own? In any case, you've reminded me that you make a kick-ass screen that...
by TheRayTracer
Fri Mar 04, 2016 8:25 am
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

Please post what you have attempted. Do you have a wiring diagram? What part of the datasheet do you not understand?
I can get the values of x, y and z with my programming in python.
I have an acceleration of 2g, but never my values ​​are all 0.
:roll:
by TheRayTracer
Fri Mar 04, 2016 12:16 am
Forum: Other projects
Topic: Raspberry for archaeology
Replies: 8
Views: 2006

Re: Raspberry for archaeology

A bit late to the game but my wife is currently taking Anthropology with a concentration in Archaeology. I just received a RPi2b for Christmas and was wondering if there is anything anybody has thought of for this type of use. if you added a GPS module and a camera module you could create a device ...
by TheRayTracer
Thu Mar 03, 2016 11:44 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Sub 1" color display
Replies: 9
Views: 1459

Re: Sub 1" color display

If you search ebay for SSD1331 you can many of these small displays without the card reader. The following is a device I highly recommend:

http://www.waveshare.com/product/module ... oled-b.htm
by TheRayTracer
Thu Mar 03, 2016 10:21 pm
Forum: Other projects
Topic: Free fall with accelerometer (freescale MMA845x)
Replies: 15
Views: 2906

Re: Free fall with accelerometer (freescale MMA845x)

The MMA845x device has a free fall interrupt that you can use. Look up the datasheet and "Freefall and Motion Detection" section.

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