The radio frequency receives and dispatches the circuit NRF24L01

NRF24L01 can work in 2.4 GHz- 2.5 GHz ISM frequency band, function module such as this transceiver built-in frequency synthesizer, power amplifier, crystal oscillator, modulator, it is a sincere integrated level more high wireless transceiver. Outside of nRF24L01 circuit relatively simple, and merged enhanced ShockBurst technology, among them output power and communication channel can carry on the disposition through the procedure. Meanwhile, power consumption of chip this extremely low, when not launching with power of 6 dBm, working current its only 9 mA; While receiving, there is only 12.3 mA in the working current. The controlling circuit of nRF24L01 can link with mouth of SPI mouth and GPIO of STM32 control device. It is that the constituent radio frequency of this chip receive and dispatch the schematic circuit diagram that image shows.




MC34063          ULN2003         2N3906          74HC595           TDA2822

Design Of Fixed-off-time-controlled Pfc Pre-regulators With The L6562

Two methods of controlling Power Factor Corrector (PFC) pre-regulators based on boost topology are cur- rently in use: the Fixed-Frequency (FF) PWM and the Transition Mode (TM) PWM (fixed ON-time, variable frequency). The first method employs average current-mode control, a relatively complex technique requiring sophisticated controller IC's (e.g. STMicroelectronics' L4981A B) and a considerable component count. The second one uses the simpler peak current-mode control, which is implemented with cheaper controller IC's (e.g. STMicroelectronics' L6561 L6562 , much fewer external parts and is therefore much less expensive. With the first method the boost inductor works in Continuous Conduction Mode (CCM), while TM makes the inductor work on the boundary between continuous and discontinuous mode, by definition. For a given power throughput, TM operation then involves higher peak currents as compared to FF-CCM (see figure 1). This, also consistently with the above mentioned cost considerations, suggests the use of TM in a lower power range, while FF-CCM is recommended for higher power levels. This criterion, though always true, is sometimes difficult to apply, especially for a midrange power level, say around 150-300W. The assessment of which approach gives the better cost/performance trade-off needs to be done on a case-by-case basis, considering the cost and the stress of not only power semiconductors and magnetics but also of the EMI filter: at the same power level, the switching frequency component to be fil- tered out in a TM system is twice the line current, whereas it is typically 1/3 or 1/4 in a CCM system.


Design Of Fixed-off-time-controlled Pfc Pre-regulators With The L6562 application circuits

Upgrade Parrot CK3000 Evolution with a Max232 chip

In order to make the CK3000 work well with Android phones you will need to upgrade it to version 5.25c. You could do get this done by a professional, or you could buy a rather expensive official cable. I'm making the cable myself with the help of other people who made a similar one first.


This is a simple application of the Max232 chip i have:

I used the original data and power connectors for the upgrade. The data connector has a kind of appendix to which i connected the data wires (not very professional).

I also connected the required wire between pin 9 & 10 (not showing in this pic):

The actual setup on the protoboard.
I used a standard 5V AC/DC adapter.
The capacitors are 1uF 50V (10 cents each):

And now the software process. I used a laptop and a USB-to-serial adapter.

I started using an inverter (DC-to-AC adapter) and it faild almost always. Later i switched to a wall socket and it went better.

* Update process and symptoms:
- Select CK3000 Evolution.
- Select Serial update.
- Select 115200 baud.
- Wait for "XPRAM downloading". Progress bar should not move yet.
   - If progress bar moves there may be something wrong.
   - If it says something like "Cannot set baud rate" probably the wire between pin 9&10 is not ok.
   - If it says something like "Cannot open port" disconnect the usb device, click back and next.
- Power on the parrot. After 1 to 5 seconds progress bar will start moving. It will take about 10 seconds to finish.
   - If you get an error like "Cannot send data" there may be a bad cable.
   - If the bar loops over and over something is wrong. Better try again.
The rest of the process is relatively fast except the "Flash programming" which takes more than one minute.
It can randomly stall or throw the "Cannot send data" error at any time. If it happens try again.
* Myths:
- "If you put two CK3000 close to each other they update the firmware automatically". It didn't happen to me.
- "You can do a wireless update with a bluetooth virtual serial port". I wasn't able to create a serial bluetooth connection. Parrot officially only supports cabled upgrades for the CK3000.