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rbasoalto

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About rbasoalto

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  1. rbasoalto

    Parking Sensors

    Ever thought of mounting on the floor, in the middle of the parking spot? Like a cat-eye. You could embed it in clear resin and measure IR reflection on the top. You could even try these cheap not-so-sensitive magnetometers (compass) to measure for changes in magnetic field, and see if that's enough. Other idea could be to use thermopile sensor, try and sense the heat of the engine when the car arrives, but you'd have to sort out the problem of sun heat, and the gradual cooling, which later could mean that the car's temp is indistinguishable from the night's sky temp. A wire loop is also not crazy difficult, but you'd need to cut through the pavement to get a big enough loop. And it won't be very inconspicuous, especially the installation
  2. rbasoalto

    C++ library with C project

    Depending on what compiler you're using, you should be able to include the cpp library APIs using extern "C++" declarations. extern "C++"{ #include "cpp_header_file.hh" }
  3. rbasoalto

    Stellaris LaunchPad IMU.

    Awesome! I was in the middle of doing the same thing by hand. I bought a very cheap GY80 clone off ebay, and so far I've managed to read the accel and gyro. I haven't messed with the magnetometer nor barometric pressure sensor yet. I think your work will be a good resource to get my IMU finished and ready for my experimental quad based on the Stellaris.
  4. rbasoalto

    Quadcopter on the cheap!

    A couple of days back I stumbled upon the Crazyflie, and its firmware source code. It's running on a STM32 (Cortex M3) so it should be easier to port than arduino code. Besides, it's using FreeRTOS (and we're planning to do the same). It's definitely worth a look.
  5. rbasoalto

    Quadcopter on the cheap!

    OK, a long time has gone by... I finally made the choice and got the motors, ESC, propellers, and a frame from DX.com. I know there are better places to get these parts, but DX.com had a good price and variety. For around 100 USD I got everything I need to make a "stable flight" prototype. The only things missing are batteries and radio. A friend of mine crashed his R/C airplane and gladly donated the radio for this project. And batteries... let me first get this thing off the ground tethered, and just then I can think about batteries. On the software side, I'm partnering with a friend with lots of experience in MSP430 (although not so much in control systems), but I think we can learn something from ArduCopter code, or similar projects, and port them to the Stellaris. 32-bit architecture at 80 MHz and hardware floating-point unit might come very handy here. The first steps will be getting the Stellaris working nice with Mac/Linux and hopefully with gcc. Then we're going to focus on modules: reading the sensors, controlling the motors, reading the radio commands, and debug output (maybe stream debug messages through CC1100 radios, or spit them through UART with a HC05-like bluetooth module). Then comes the hard part of putting inertia and motors together with the control system. Finally, getting the quad to obey radio commands. We're also thinking on integrating gps waypointing capabilities for semi-autonomous navigation. This will probably not be of too much use, since we're not expecting battery life to exceed 10~20 minutes. We'll have to measure the system power requirements and find a suitable battery pack to fit our power/weight needs. PS: for those of you who are curious about the parts used, here's the list: A2212-6 2200KV Brushless Motor Set - Golden http://dx.com/p/41211 Mystery Speed Controller Pentium-30A for Brushless Motors (300/450 R/C Helicopters) http://dx.com/p/34338 4-Axis HJ450 Multi Flame Wheel Flame Strong Smooth KK MK MWC Quadcopter Kit - Red + Black http://dx.com/p/124486 10 x 4.5 1045 Rotating Shaft Propellers for Multi Copter - Black (2-Pair) http://dx.com/p/123222
  6. OK, let's see if simplicity can win http://forum.43oh.com/topic/3016-very-simple-ir-remote/
  7. rbasoalto

    Very simple IR remote

    Hi! I made a very simple IR remote control with a MSP430G2211, a 4x4 keypad, and an IR LED. I wanted to make a remote for my car radio, but for the time being, it's a Sony TV remote. You can see the code (mspgcc) at https://github.com/rbasoalto/sonyremote A couple of pictures... The code could use a little rework, but for a quick&dirty hack, it's working pretty nice. BOM: Keypad IR LED MSP430G2211 + socket Resistor for RST (it's inside the socket) Decoupling cap (probably not needed) Salvaged iPod Li-ion battery AMS1117-3.3 regulator (just the one I had lying around...) Assorted connectors Perf board Next steps: Program new codes using keypad. Add a receiver module to enable learning of new codes. Higher power IR, using a transistor or MOSFET and a couple of high-intensity IR LEDs
  8. rbasoalto

    OLIMEXINO-5510

    Long time, no post! I've found a little spare time to play with the F5510 Olimexino. It was pretty much impossible to get the USB BSL working (I'm a Mac user ), but I could use a Launchpad to program it through SBW. The board is tiny, feature-packed, and a pretty good deal IMHO. USB is definitely a selling point. Besides, for some, Arduino shield pin-compatibility is a plus. Olimex's UEXT port is also useful. With a bit of pin hacking I got one of these 8-digit displays from DealExtreme (http://dx.com/p/81873/) working directly off the UEXT connector, pin compatible. For me it was also a pretty good deal, since snail mail in Chile is sloooow and unreliable; having these available in a brick-and-mortar store is priceless.
  9. rbasoalto

    Garage door opener

    Yeah, I guess accepting only increasing numbers is fine. If you use a sufficiently long counter (32 bits?), it'd be fine. I doubt you are ever going to get 4 billion events in the lifetime of the system. You'll need to swapt the battery first (and then you will have to resynchronize somehow). I think a simple synchronization scheme will do. Something based on button pressing and/or jumpers (say, put a jumper in the remote to set it to "sync mode", and then press a button on the server to transmit a new key and start counter at 0). If you get sophisticated, you could have multiple remotes with different private keys (and their respective counters), thus allowing you to revoke access to one particular remote, or selectively grant access to different remotes according to some parameters (time of day, door requested to be opened [if you put more than 1 door controlled by one server], etc.).
  10. rbasoalto

    Garage door opener

    Very nice! Maybe you can have a look at http://en.wikipedia.org/wiki/HOTP for security. It's the kind of cryptographically-secure unpredictable sequence generators that banks use for two-factor authentication. Google's two-factor authentication uses it too. The idea is that you apply an HMAC function (some kind of hash involving a private key) to a counter. Both transmitter and receiver need to store this counter. Since both will usually be in sync, the HMAC received can be compared to the expected value, based on the shared private key, and the counter. If it fails, it can also try a few counts ahead too, in case the button was pressed accidentally out of the receiver's range. Although banks and Google use a time-based algorithm, it's essentially the same, but using the count of 30-second ticks instead of an event counter. I think I've seen a version for the Chronos that is compatible with Google Authenticator. Should be trivial to adapt. Since you will need to store a counter, FRAM would be ideal for zero-power-standby. But you can also use flash, or just have the MSP sleeping in LPM4 the whole time and wake it, with an interrupt from the button, for transmission (at a few uA it shouldn't be noticeable). In this last case, you could use a three-way handshake, much like TCP/IP sockets, for keeping the counters in sync. Something like [*:3rhtxy43]Remote: HEY, the current code is 123456. [*:3rhtxy43]Receiver: OK, please come in. [*:3rhtxy43]Remote: Thanks! Increment the counter! (I will increment it too) I could continue giving ideas for centuries, it's a very interesting topic. Cheers! I hope you're not locked out!
  11. rbasoalto

    Quadcopter on the cheap!

    These days everything slightly related to DIY electronics is marketed as "for arduino". This IMU module is just a set of 4 sensors on an I2C bus, making it perfect for anything I2C-capable, and over just 2 wires! The 400khz bus should be more than enough for this purpose.
  12. rbasoalto

    Quadcopter on the cheap!

    I've seen a lot of DIY tutorials, etc, but most are using carbon fiber frames, etc. Have you seen a simple guide for something waaaay cheaper? I'm thinking acrylic frame (hand-cut, of course), and cheap motors and ESCs. My first goal is to get it flying, with no human control. Something like taking off, flying steady-still 20cm off the ground, then landing. I'd also love to read something on the control: is proportional enough? or should I go for PID? Also, I'm thinking it's wise to begin with accelerometer-only control, and then start experimenting with gyros. Should be enough for this purpose.
  13. rbasoalto

    Hola from Chile

    Oh yes, check this post: http://forum.stellarisiti.com/topic/222-quadcopter-on-the-cheap/
  14. rbasoalto

    Quadcopter on the cheap!

    Hi everyone! I saw this IMU (3-axis accelerometer + 3-axis gyro + 3-axis magnetometer + pressure altimeter) for $21 on eBay (link), and the $5 Stellaris launchpad, and I immediately thought: QUADCOPTER! Already placed the order for the IMU and Stellaris, and I plan to design a Boosterpack to connect motors, sensors, and probably a sonar ranger to the floor and/or ceiling (for indoor flight). Anyone has any experience with these flying monsters? Thanks!
  15. rbasoalto

    Hola from Chile

    Hi! I'm a total newbie here, I'm hoping I learn a lot from you guys. Already ordered a couple of Stellaris Launchpads! See/read you around!
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