Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Have Some Serious Fun with PingPong-CDC!

Does anyone here the ping-pong lovers? Well, do you know that playing this game is no an easy task, as you need to have the speed, skills and sharp mind if you want to beat your opponent off! If you one of the ping pong fans but you just don’t want to sweat a lot here, then would you mind to build a PingPong-CDC? This PingPong-CDC project is a very simple USB frequency hopping spread spectrum RF modem or also known as FHSS. Basically, the modem is based on the PIC18F2550 and the Semtec XE1205 RF module. However, this module doesn’t include any MAC or protocol layer like other modules did! The main purpose of this project is to demonstrate the correct ways to write a FHSS MAC layer and use the USB feature to interface it with a PC through CDC and WinUSB. It might sounds complicated to you but it wasn’t! For your information, it’s easy to change the software to experiment with different protocols, since the protocol is not a hard-wired type. In addition, a utility for… Continue reading

It’s Ping Pong Time!

Are you a Ping Pong lover? Would you mind to play the Ping Pong all day long? Oops, hold on a second! What I tried to mean here is the PingPong-CDC, which it’s needs to use frequency hopping techniques to create a bidirectional link, but not the real Ping Pong sport that you making you sweat lol This PingPong-CDC project is a homebrew USB frequency hopping spread spectrum RF modem (FHSS). Basically, the modem is based on the Microchip PIC18F2550 and the Semtec XE1205 RF module. The module doesn’t include any MAC or protocol layer and that’s what this project tries to implement. The main purpose of this project is to demonstrate how to write a FHSS MAC layer and apply USB into this project to interface it with a PC through CDC and WinUSB! The non hard-wired feature has making the protocol becoming easier to change or modify the software to experiment with some of the different protocols. Beside that, a utility for pairing and configuring modems is included as well. Since this is a simple to develop electronic… Continue reading

It’s an USB Audio Streamer V1.0 and Not a Steamer!

Do you have the idea to create a USB sound card, which is based on a PIC interface? Today, you have the chance to learn to develop an USB Audio Streamer V1.0, or it is a microchip PIC based USB sound card. For this project, the hardware part is based on all Microchip, and the software part uses a modified version of Microchip USB framework. The main objective of this custom interface is for programming the device serial number and upgrading the firmware. Hardware Part The Microchip PIC18F2550 USB processor is used as the sound card purpose. The processor is clocked at 48MHz, where it is the maximum rate for this processor. The microcontroller is being connected via the SPI port to the Microchip MCP4822 12bit D/A converter. The separate port is being used in the project to control the volume and enable it to run inside the processor at a different priority level. Software Part The main software part that consist in the USB audio streamer are the audio card firmware, the card INF file for the custom interface,… Continue reading

PIC18F2550 based harmonic distortion meter

This simple device, designed by Wichit Sirichote, measures the quality of AC voltage. The device measures 3rd harmonic which is used to find the distortion value comparing to fundamental frequency.   Device calculates DFT of signal which is captured via step down isolation transformer and 10-bit ADC. Testing showed that clean sine wave gives less than 0.5% of distortion, while square wave gives about 33%. Project description includes detailed measurement theory outline and practical examples as well. Project is built on test board which was developed for general purposes. Source code is available for download. Continue reading

Low budget graphical LCD oscilloscope

Oscilloscopes built on 8 bit microcontrollers don’t give much power but they can serve is specific areas where signal frequency is really low. This one is built by using PIC18F2550 microcontroller which can give 12MIPS calculation power maximum. Actually scope is mostly limited by internal ADC. In this project 60kHz of sampling rate was reached. This is still enough to view few kHz signals. Analog signal enters directly to ADC input without any amplifier or buffer circuitry. So voltage is limited to 5V. In other hand design is kept really simple and can be repeated on any PIC18F2550 based development board. Firmware can be downloaded by using bootloader which can also be found in project page. Continue reading