June 4th, 2009

4 Digit PIC Counter

4 digit PIC counter

A counter is a very useful tool, i for one could use one when I’m winding coils. These days a counter project caught my attention, because it can be configured for many applications. Basically it’s a 4 digit decimal counter that can go from 0 to 9999 in either direction, can stop when it hits the maximum counting value or can be left in free run.

The maximum counting number can be set by the operator to a desired value, which is stored in the EEPROM of the PIC16F88. This is very helpful, looking at my coil winding example i can set this way the number of windings. You can also set it to count up or down and has an overflow output which can be used to control an external device once the counter reached the preset number, in my case to turn off the winding motor.

The clock input is port B0 of the PIC and can be set to count either rising or falling clock fronts with or without zero suppression. Schematics show a debounce circuit to be used with mechanical contact switches at the clock’s input, which will accept 5V logic only.

The counting is displayed on four 7-segment LEDs and operation mode is shown on other four LEDs. D7 will indicate overflow, D8 Count Hold and D9 and10 will indicate it’s counting up or down. The whole display is multiplexed, more information about that you can find here. There are five push buttons you can use to configure the counter.

Schematics, source code and hex file for PIC as well as detailed explanation of operation can be found in the link.

4 Digit PIC Counter: [Link][Via]

June 2nd, 2009

Mini-sumo Robot

Mini-sumo Robot

If you’re into robotics then you must know about the sumo competitions between autonomous robots. Seeker II is one of the competitors who proved his good design in battle. In this project you will have all the information you need to build yourself a mini-sumo robot.

The Seeker II is using a PIC16F876 providing four analog to digital converters for sensors, timing functions, a PWM output to control the motors and also allows for future calibration, testing and debugging. The robot is equipped with two range finding sensor from Sharp, GP2D12, placed right at the front and connected to analog inputs A0 and A1 of the PIC. Other two Fairchild QRD1114 sensor are placed at the bottom and used as edge finders and are connected to analog inputs A2 and A3.

The robot comes with two wide wheels which offers a good amount of traction, each wheel having its own motor. The motors, Faulhaber 1717, are driven by a SN754410 h-bridge IC controlled by the PIC. If the EN input is set high than Y output of the h-bridge will be same as the A input, if EN is set low then the Y output is turned off on the SN754410. The PIC controls the speed of the motors with PWM.

Ports C7 and C6 are used for serial communication, to watch, test and debug software, as well as to read log files from EEPROM.

In the link you will find block diagram, schematics and code for microcontroller.

Mini-sumo Robot: [Link]

May 3rd, 2009

Monitoring Weather

Weather Station

I remember back in 1996 after i saw for the first time “Twister”, i was so hooked on ways to measure weather parameters by myself. APT reception of weather satellites, VLF radio, temperature monitoring… you name it, my backyard was filled with antennas, each one bigger than the other. Now when i found this awesome weather station project all those memories returned and my soldering station is heating up.

This weather station measures the most important weather parameters: temperature, pressure and relative humidity. You can select to view temperature in Celsius or Fahrenheit degrees and pressure in mbar/hPa or mmHg. The station can also measure the temperature from a remote location using RX,TX433 wireless modules.

The data is displayed on a LCD along with the date and time, the highest and lowest temperature in the past 42 hours and a graphical histogram. To increase its autonomy the weather station has a sleep mode, it wakes up only to gather the data from the sensors, memorize it and display it. Looking at the schematic you will see it uses MOSFET transistors as switches controlled by the PIC18F452 to power up sensors and RX/TX modules to preserve battery life.

Operation of the weather station is done using the three buttons. One button brings the menu and the other two are used to navigate in it, or too navigate through memorized data.  Pressing any of these buttons will awake the station from its sleep mode. Another thing to mention is that the data will not be lost if the station loses power.

The sensors used are MPX4115A for pressure measurement, TC77 SPI for temperature and H1 sensor takes care of humidity reading. The H1 outputs a capacitance so its used with a 555 oscillator, whose frequency depends on the humidity reading. PIC18F452 is the brain of the receiver station and PIC16F84 takes care of the transmitter.

All schematics, PCB layouts, hex files and source codes are available in the project.

Monitoring Weather: [Link]

controlling the flight of a zeppelin

A teams of students from Colorado State University have designed and built a PIC-based circuit to control the flight of a blimp. You can control it manually by remote or let the zeppelin find it’s own path to a specific destination that is designated by an infrared beacon.

The remote control has a 204 LCD display which shows the commands and a 12 key keypad from which you can control take off, land, forward, reverse and steering commands. The zeppelin also has an altitude controller with ultrasonic sensors. This makes it go higher if it detects the ground too close or go lower if it’s altitude increases too much.

The thrust is given by two motors, each set at the end of a horizontal bar. A servo motor controls the angle of this bar and thus the direction of the thrust. There are four IR sensors each placed in the four cardinal points. These sensors serve the autonomous flight mode. The IR sensors output a low pulse when it “sees” the beacon so the zeppelin will follow the direction of the sensor which gives out the most pulses. The beacon is made with 16 IR LEDs driven by two 555 circuits.

The altitude control is been taking care of by a PIC16F84 designated IC2 in the schematics, steering is done by a PIC16F88, IC3, and all communicate with the control center a PIC16F874, IC4. Thrust motors are driven by SN754410, IC5 in the schematics. In the remote control you will find a PIC16F877P who takes care of all the RC functions, reading the keypad, displaying characters on the LCD, sending audio message to speaker and sending serial commands to the zeppelin.

Controlling the flight of a Zeppelin: [Link][Via]

March 19th, 2009

Wearable POV unit

Wearable POV unit

In one of my previous post I presented a simpe handheld POV device, it was a little bulky not really suited for a true handheld device. If you are interested of building a similar gadget this is the thing you need, small enough to be mounted under your wrist watch and has a mercury switch to synchronize the display to the movement.

The entire project is open hardware, even the gerber files are available, very nice indeed. Although the pcb’s will be hard to replicate because of the small size and smd components, but not impossible.

My choice would be to redesign the pcb for an ankle mounted POV, that way the pcb could get bigger, there will be room for larger batteries, and if you make two of them you can use it instead of ankle weights when jogging or at fitness trainings.

Wearable POV unit: [via] [link]

© 2007-2011 YourITronics | Any logo, trademark and project represented here are property of their respective owners | Wordpress | Privacy Policy    RSS