How to Build a 4-Channel Wireless Sensor System: Page 3 of 3

Do you have a DIY monitoring project that could use a boost? Here's how to create a 4 channel Wi-Fi sensor system with a 200ft increase in range over most projects you'll find online.

are asynchronous, the controller code’s transmission protocol is bit synced, at the receiver and evaluates the received data for collisions as well as includes evaluation of the received checksum provided from the transmit sensor controller.

I used a small antenna (17cm), pre-formed and purchased on-line, to fluff up my sensor range. Depending on the specifics of the transmitter/receiver used, transmitter voltage, and the loads presented by the transmitter to receiver path, sensor data, for my link was available from up to 150 to 200 feet. Other OOP link-based products or any transmit telemetry set that will replicate, what is essentially a pulse width modulation input string, would increase the available sensor range to portions of, or multiples of a mile.    

Those with any questions are welcome to contact me via email. 

Parts list:

Receiver              
Description   Part reference   Qty   Digikiey # Nnotes
controller   PIC16F676   1   Digikey Stk #: PIC16F676-I/P-ND other packages available
433MHz    OOP, 5V   1     XD-RF-5V
antenna   24 ga copper wire    17cm      
LED   red   6     or equivilent
resistor RPAK   6-470ohm/w bussed   1     or discrete resistors
resistors   4.7K   1  

Digikey Stk #:

OK4725E-R52-ND

 
cap   10uF   1      
regulator   78L05   1   Digikey Stk #:

MC78L05ABPGOS-ND

optional */not shown
proto/perf board   .1" centers/clad 1 side    -   Digikey Stk #:

438-1019-ND

as needed
socket    14pin DIP   1   Digikey Stk #:

609-4713-ND

optional
Xmitter              
controller   PIC12F509   1   Digikey Stk #:

PIC12F509-I/P-ND

other packages available
433MHz   OOP, 5V   1     XD-FST
antenna   24 ga copper wire    17cm      
regualtor   78L05   1   Digikey Stk #:

MC78L05ABPGOS-ND

*
sensor   DHT22   1     DHT11 or other equvilent
resistor RPAK   4-4.7Kohm/w bussed   1   Digikey Stk #:

CSC4.7KE-ND

or discrete resistors
resistor   1.5Kohm 1/4W       Digikey Stk #:

OK1525E-R52-ND

 
diodes   1N4148   3   Digikey Stk #:

1N4148W-FDITR-ND

leaded shown,  *
cap   10uF   2     *
proto/perf board   .1" centers/clad 1 side    -   Digikey Stk #:

438-1019-ND

as needed
up-convertor   3.3 to 15V    -     XL-6009 optional */not shown
socket   8 pin DIP       Digikey Stk #:

609-4717-ND

optional
* depending on power source, configuration and or and transmitt voltage requiremnets               

 

[All images courtesy William Grill]

Comments

My contact link is: [email protected] The code for both the sensor and receiver controllers should be available with the article. I have the originals and could also provide them. They are coded in assembly language with comments.

Jerald Cogswell's picture
Nice project, William. I will be emailing to ask for source code, etc. If I understand correctly, you created your own simple protocol involving a packet header, device ID, data, and checksum. The Dynamixel motors use a similar protocol with the checksum being calculated as the low byte of the bit inversion of the packet length.

>>> If I understand correctly, you created your own simple protocol involving a packet header, device ID, data, and checksum. I'd also be interested in learning how you implemented your protocol. A good protocol is the key to using these very simple and cheap 433MHz transmitter/receiver sets. That super-regenerative receiver needs to be "primed" with some kind of header so that it can properly set its thresholds for detecting the data bits.

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