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
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
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
During time, need of simply and portable logic analyzer appears. The idea of interface connected with personal computer seemed to have been very suitable. Then I tried to find out on the web, if such device does exist. Answer is yes – perfect project has been done already. This is PicLA – a very low cost logic analyser. You can find it on the link http://pe1grl.khds.nl/picla/picla.htm , where it’s completely described. Only one thing is missing – PCB. And this is the reason of this post.
As my first project with PIC microcontrollers, I chose for me DCF clock. The main reason for this was, that it was very complicated to get LED clock ( visible at the night ) with DCF synchronising possibility. The second reason, which appeared, was unavailability of alarm clock, where alarm is active in certain (working) days only. So arose the basic idea.
