Note: I am not expecting this to become a product that will be sold by Lynxmotion and for sure I won’t be going though the hassle and issues involved with selling a product!
But: I have been having a lot of fun with Seeeduino Mega shield and have found it a lot of fun to use an Arduino Mega for different projects. However this project had some downfalls. In particular it relied on using a Seeeduino Mega board, that is a nice board but it is not any standard form factor. Also they did not solder in any additional headers for the IO pins beyond the standard Arduino (non-mega) pins and later they stopped shipping the additional headers. So at best you were left having to solder all of them in and at worst you had to find someone who sold those additional headers and then solder them in. Then when you finished soldering all of them in and assembled the shield, it was a real challenge to align all of the IO pins and get them to all go in… Another downside is they have not updated the design of the board to keep up with the official Arduino boards…
Also there are now newer boards that using the official Arduino Mega form factor. This includes one of the Pic32 boards and will soon include the Arduino Due when it is shipped. So for my own fun, I decided to try: When in Rome do as the Romans do… I am now playing around with a Mega shield, which will obviously be larger than the standard boards that Lynxmotion sells. Here is a look at the WIP…
Note: I have lots of cleanup left to do. But I think it is promising for my own work:
All 16 analog pins have 3 pin headers.
Have 32 of the digital pins with 3 pin headers. 2 have PU for PS2
Have (GND/TX/RX) headers for all 4 USARTS
Have 3 buttons, 3 added leds, plus the standard one on D13
Speaker.
4 pin I2C connector to match the Botboarduino.
Several mounting holes: the ones I filled in Red match the Lynxmotion ones, could not fit forth one without hitting IO pins…
Since this is for my own use, I am thinking of making the board cleaner and maybe have all of the 3 pin connectors where the signals are toward the outside of the board and the ground toward the inside… This makes it much easier to get the signal wires routed to the appropriate stack able header pins.
Thoughts? Maybe thinking of posting in main forum later?
I see your having fun
Well, this sort of confirm my irritation about their form factor with a main board with only female pins. Mega board + Mega shield + SSC-32, thats a lot of boards! No wonder why I like the ARC-32.
But your shield would sure help you to get access to what you want. I’m still thinking that a board like this with SSC-32 features would be interesting?
I am also not big on the idea of shields, but would like to continue to experiment with the newer more powerful Arduino Megas, Chipkits and hopefully soon the Due.
So I figure I might as well set my self up to have fun with them. Soon I will probably order 5 boards to be made for myself and populate 1 or 2 of them to start off with. Will also post, the design files, Gerber files and parts list, so others could build them if they so desire… Here is a look at the current one:
Yes XBees would be nice ! Will try. Will keep copies of this design and start modifying. If I can get it to work, it will be a very tight fit. I will need to modify/remove some functionality/flexibility. Need to figure out which IO pins to connect XBee to. Should I have option to RX0/TX0? Most XBee shields do this, but on some implies you have to remove the XBee to use the USB to program it… Personally don’t like this. Would prefer a different USART. Room depending could add jumper connections, that default to what I want to use. You can then always remove the shunts and use jumper wires to connect to other places…
It may turn out that maybe some of the voltage selections will need to be simplified, like in some cases maybe only 8 pins can change or the like. Also may get rid of one or both internal mounting holes. These align with the current Mega board, but the first version (the one I have), did not have them, nor does the Max32. Thought they might be nice if you had the newer Mega256, you could use one or both of them with bolts or the like to hold two boards to each other…
Also could maybe jettison the ISP header as I have never used one (except maybe to get +5v or GND…
Yes, I will probably add a new thread up on main forum, talking about this.
Yep - Forgot to mention here, that I do believe that the Chipkit (pic32) stuff should easily handle the servos as well probably a lot better than ARC32. I will also assume that the new 32 bit Arduino will as well. I am also interested in trying with standard Arduino Mega to see if it can handle it on it’s own. I may cobble up a new Hex robot. I think I may have 18 servos, if I disassemble one of my two brats. I can currently test with Seeeduino mega with the current shield prototype.
FYI - It looks like Basic Micro released the new version of the Arc32 board, that now has jumpers to connect VS1/VS2/VL… Datasheet has not been updated, but getting questions on their website.
I did remove the two internal mounting holes and the ISP connector. I also removed the I2C connector that I had added.
But I did get the XBee in, with LEDS for RSSI, RX, TX. Plus 2 Jumpers for connecting to the RX/TX pins. The default jumper goes to USART3 (by shunts). I am using two resistors as a voltage divider to drop the TX voltage from USART3 to go to the XBEE. For RX I am using the FET… like Mike has to convert 3.3V from XBee to 5V… Hope I have it correct… Also I added an EEPROM to the I2C with 2 PU resistors…
Assuming they work out OK, I am more than happy to share . But not sure what to say here as each board will probably take me a day to solder as I am pretty slow at this I also do not want to get into the liabilities of selling a product.
I am more than happy to send Jim some of the fabricated/non-populated boards to send off to you. As I mentioned before, I plan to publicly release all design information including the gerber files, such that anyone should be able to order them from their favorite board manufacturer. I have normally ordered 5 boards at a time from pcbfabexpress (pcbfabexpress.com/preview_specs.jsp), with 5 day turnaround, comes out to $15 per board plus shipping. If I order more the cost per board goes down. Not sure if there is some cheap service to actually populate the boards or not. But we can work on this, as the board progresses.
I hope things are going well for you. In the next few hours I will make an order for my first batch of boards. I will probably do my default of 5 boards with 5 day turn-around, which costs me $75 plus shipping, so yes they are not too bad, especially since having them do 1 board costs $65, so might as well order the extra 4. Assuming that it works at all, I will probably assemble 2 maybe 3 myself (Arduino Mega - I have, Chipkit Max32 - Arrives Wed, Arduino Due - ???). I am pretty sure that the servo connections will work, so the main testing will be to see if I got the XBee hook-up correct as well as the EEPROM.
May have pointed at wrong shield. The one you are talking about is the one that went on Seeeduino mega board. I think details in this thread viewtopic.php?f=44&t=6350&start=138
! Will try. Will keep copies of this design and start modifying. If I can get it to work, it will be a very tight fit. I will need to modify/remove some functionality/flexibility. Need to figure out which IO pins to connect XBee to. Should I have option to RX0/TX0? Most XBee shields do this, but on some implies you have to remove the XBee to use the USB to program it… Personally don’t like this. Would prefer a different USART. Room depending could add jumper connections, that default to what I want to use. You can then always remove the shunts and use jumper wires to connect to other places…