Has anyone tried to hook a Basic Stamp 2 conntroller up to the VEX conntroller? I would imagine that this would be quite difficult, but it would allow for less expensive programming.
The Stamp BS2 is excellent for controller for making for Vex robots! Using the Stamp and a simple PBASIC application, I have been able to control a Parallax Serial Servo Controller (PSC) that can control up to 16 Vex motors and servos. Please check out my Erector Set and Vex based Robots featured in the ROBOT Magazine article.
Hmm, I didn’t see any vex bots, wrong article? (I did not read the article, I just skimmed it.)
The answer to your question of using Parallax Stamp for Vex applications is clearly yes, and examples are provided in this article. The article does mention Vex and Erector Set and also provides links to the Vex Forum. In addition it mentions using the Parallax BS2 for robotics, along with making a DIY PIC18F8720 Robot Controller (BioStamp).
For more advanced robotics using other controllers, you may also want to check out the following Circuit Cellar article that featured a Vex Robot on the cover.
Can you provide a schematic for connecting a BS2px with the Vex Microcontroller using the TX and RX ports and the BS2px’s I/O pins (using the Serin and Serout commands)? Some code would be helpful too.
I can provide you a BS2 or BSX application to control Vex motors and servos along with the schematic that I used. In other words, you do not need to use the Vex Controller; instead you will just need to build the simple circuit that is described in the schematics.
As for using the Stamp BS2/BSX to control the Vex Controller, it may be possible to do but becomes very involved. The reason is that the Vex Tx and Rx ports (USART) are configured for 115200 Baud, 8-Data Bits and 1-Stop Bit, whereas the Parallax BS2/BSX can only handle a maximum baud rate of 9600 Baud and even the Parallax BSP can only handle a maximum of 19200 Baud. What this means is that the Vex DDT or JVEX firmware needs to be modified to handle the slower baud rates and once this is done, the Stamp BS2 application needs to send DDT PWM messages to move the selected motors and read the sensors, which will use up most of the available on-chip EEPROM and SRAM.
Have you loaded the DDT Firmware or the JVEX firmware onto the Vex Controller using the IFI Loader and Vex programming kit?
If you could provide a schematic for connecting the BS2px to the motors and servos that would be great.
As for connecting the BS2p to the Vex PIC, I understand what you are saying and at the moment I will keep away from this project.
Here is the schematic for the Stamp BS2/BSX version of my DIY Antique Robot (using Erector Set parts) that I have used to drive Vex Motors, Vex Servos and standard or modified RC Servos. In addition it also controls a Polaroid 6500 Sonar Ranger and can read a Sony SIRC Protocol TV Remote Controller. Just use the parts of the schematic that you need, the rest is “optional”. Let me know if you have any questions with the schematic and I will be glad to clarify them for you.
Thank you for the schematic tswift1
I don’t have time at the moment to look to thoroughly at it, but I will get back too you soon if I have any questions.
Here is the associated Parallax BS2/BSX code that I used for my Antique Robot made from Erector Set parts and modified RC Servos, which ran autonomously or by remote control using a Sony TV Remote. The complete project was published in Nuts & Volts magazine a few years ago. It may need to be customized for your application and the Vex Motors may need slightly different motor commands and you may also need to remove or comment out PBASIC code for sensors that you don’t plan to use.
I also have DIY Motor Controller schematics for the standard two wire DC Motors used in the Vexplorer robot if you are interested in a fully programmable Vexplorer robot.