It is perfect to have fast way to produce PCB. For those of us, who have CNC milling machine available, is to mill the “printed” circuits one solution. It requires to have suitable milling machine with sufficient accuracy, working tool (HPTec V-groove cutter type 802.9 seems to be ideal for me, it is possible to buy it at http://www.cncshop.cz/drazkovaci-freza-30-600-v-profil-typ-802-9 ) and of course the software, which can convert PCB design to G-code for CNC milling machine. As far as I know, one of the most widely used PCB design software especially among the enthusiasts is Eagle from http://www.cadsoftusa.com/ . One of its feature is create the user language program (ULP), which can be used for many purposes and one of them is to generate G-code.

(more…)

I have published accumulator monitor (called LiXXX watchdog) one year ago. This design uses buzzer to signalize low voltage cell(s) of three cells LiPol / LiIon / LiFePo battery.
Now it’s the time for more sophisticated entrance. One possibility is using of JETI DUPLEX 2.4GHz system. It allows to transmitt data back to transmitter (TX module) and display them with JETIBOX. The idea to use this feature for monitoring state of battery cells is then obvious.

JETI DUPLEX battery monitor

(more…)

Although I haven’t got any RC car, my friend ask me for programming of RC car lighting system. I produced the code for the PIC16F819 microcontroller from Microchip. Finally, it can have 4 PPM channels as input (I used 3) and 12 outputs (5 of them are used) able to drive 25mA per one output (max. 200mA in total).

RC car lighting system

(more…)

There are many systems transmitting on 2.4GHz available at the moment. Some of them are able to transfer more than 8 channels typical for standard PPM modulation systems. One of example is made by the czech company “JETI model” http://www.jetimodel.cz/index.php?page=products&old=0&category=4 . Their system is capable to transfer up to 16 channels. It is opportunity to control more devices than model itself … camera, autonomous navigation. The only task is to merge signal from two RC transmitters with the result usable as input to the transmitter module (PPM signal too).

I solved this task with two microcontroller PIC18F252, called “MASTER” and “SLAVE”. 

RC merger

(more…)

I have acquired the Graupner MC-22s RC radio since the end of the year 2007.

MC-22s Front View

(more…)