Microcontroller based VGA or TV projects always attract me - because information is displayed on big screens with small hardware. In this particular project there is a PIC 18F2550 microcontroller used with USB interface. Device is capable to generate 640×480 VGA signals where image resolution of 16×32 is reached what is enough to construct simple digital clock image.

As USB device it is operating as simple HID device which receives time events every second and updates VGA image array with new time value. Nice project to experiment with and learn some new stuff - especially in USB part. Source code for download is here.

This is really small speed controller build under AT90S2343 microcontroller.

It can be used on very lightweight model like RC plane. Controller simply ramps up or ramps down motor speed depending on buttons are being pressed. If no button press is detected then controller ramps motor down to a stop in order to prevent model fly out of transmitter range.

Controller itself weights about 0.3grams and it size is 9×12mm. It is capable to drive 1.5A motor by using an IRLM2502 mosfet. All files are provided if you want to build it by yourself, or you can buy one for few Euro’s if you don’t want to mess with soldering.

“If your freezer fails you may have meat or other frozen stuffs ready to eat. Re-freezing, not generally considered an option, may be an alternative for you, but may be also a risky business. While for a short time, a freezer should maintain an acceptable temperature to keep everything from beginning to defrost, it would be nice to know if the freezer contents have been compromised and for how long. For instance…power could be lost over that weekend you spent at the lake with the power returned several hours later. This exposes the contents to the ravages of spoiling without you even realizing it…”

PIC12F506 microcontroller reads temperature data from MAX6510 temperature sensor. As device is powered from batteries - temperature readings are performed periodically in order to save energy. Alarm system has some fancy algorithm which allows interpreting errors correctly. More information about operation and building you can find in downloadable word document.

If you are thinking to move on DSP, maybe dsPIC microcontrollers can be a good start as they have DSP engine built in that allows fast multiply and divide operations with arrays. For instance dsPIC30F2012 is a 16bit 30 MIPS MCU with 24kB flash and 2kB of RAM, 8channel 12bit ADC and other common peripherals. With these parameters you can start simple DSP applications before you move to better and more powerful.

This test board is really simple to build - simple LM7805 voltage regulator in power supply side, and MAX232 for RS232 interface. Other I/O pins are left open for prototyping. Seems to be that dsPIC’s aren’t very popular among hobbyists as there aren’t many projects published in the internet. But thanks to built in DSP engine things can change.

If you want to do some fun stuff with your TV screen - you can build simple Video overlay circuit that practically require few components. Circuit simply captures the start of video frame and outputs text (could be graphics also) on top of video image.

With video overlay you can do lots of things like showing time, alert messages while you watching TV and many more. Simple operating source code for WinAVR can be downloaded here.