Friday, October 21, 2005

Four Month Update

Due to being unsettled (moving, bought a house), I've had to put my projects on hold for a bit. Well, I'm back now.

New tools: Mini metal lathe. I can now form my mechanical components and get back to being an ME! Plans include components for my other projects below, and probably experiment with tool design. I'd actually love to build a CNC mill eventually, but I'll need a manual mill and lathe first. Halfway there.

Project Updates:
I'm refining ideas for the RC core to the hardware I have. I've got a few 2.4GHz point to point 250K/s or 1Mb/s transcievers that are simpler to control and will provide me with a good starting point in RF design. I'm still planning on having everything connect together via CAN bus. However, some designs have become easier as Microchip is now selling/sampling full speed 3.3V parts and is coming out with a wider array of 16 bit chips shortly.

New Projects:
IMU2: while I do have some gyros sitting around, I've recently ran across a paper about using accelerometers as an IMU, Active Tremor Compensation in Handheld Instrument for Microsurgery. While I've known about the theory for a while, what impresses me is that they've seen increased accuracy over common triple axis accelerometer-triple gyro configurations. I have a pair of Freescale MMA7260Q triple axis dynamically scaleable accelerometers I'm planning on building an "IMU Stick" with as an experiment. This should end up being smaller and lighter than any other IMU design, possibly allowing RC aircraft autopilots to shrink in size.

Air Cannon Launched Sensor Packages: I've always wanted to do this one. A 25mm bore aluminum barrel about 18" (460mm) long is used to launch (via CO2 or air pressure) a sensor package. The initial package will be sensor equipped to track various pieces of flight data. Useful sensors that may be deployed are for both search and rescue and laser tag games. Parachute deployed motion trackers, vibration and sound sensors, etc. The critical components of the design will be a concentric ring that will use a transformer effect to provide data to the microcontroller in the sensor package in barrel, non-contact. This will allow (with additional hardware) to sight a target zone, and have the electronics tell the operator where to aim to hit that target. Through controlled pressure and temperature in the expansion tank (Especially for CO2), muzzle velocity of the sensor package can be controlled. Various ways of triggering the descent parachute at the right time will be tested (timer, airspeed through air pressure sensors, etc).

Laser Rangefinder: Always wanted to build one. I've found information and effective hardware for the transmitter and reciever sensors. I've found a 25 year old schematic from an old TI optoelectronics book for a phase-difference rangefinder. With modern electronics, I can probably make a nice Time of Flight rangefinder work. This might be ideal, especially since a near IR diode was found on Digikey that has a CW output of 120mW, well above the safe range.

1 comment:

Anonymous said...

I would like to see the schematic of that T.I. laser range finder, could you email it to me please?