Hi FarmBot community,
As you may have seen by now from our newsletter or social media feeds, on Friday we announced two new FarmBots available for pre-order: Express MAX and Genesis MAX. Both of these new devices are 18m long (3x their XL counterparts) and represent the most economical FarmBots we offer when looking at the $/area metric.
If you’re interested in using FarmBot for small commercial production (such as for a farm-to-fork restaurant or larger-scale research) we think these devices will be a great fit. Or, maybe you just want to grow a truly massive home garden!
Some hardware details
Both of these kits will share nearly all of the same hardware and features as the smaller versions in their product line, though we’re still working out some kinks with the X-axis drivetrains to reliably support such long lengths. Specifically we’ve seen so far that the motors have a more difficult time pushing the cable carrier in the -X direction when the bot is in the farthest third of the bed. We’ll be able to overcome this with one or some of the following techniques, with the final design to be determined.
- Increasing the current provided to the motors by the stepper drivers (the Trinamic stepper drivers included in all kits from here on out allow software-controlled current adjustment)
- Using longer motors to provide 20% to 40% more torque
- Using smaller pulleys to provide more torque, though this also reduces the amount of tooth engagement which may increase propensity to skip
- Using gearboxes to increase torque
- Using even smaller X-axis cable carrier to reduce mass and friction
- Using a more flexible power cable with thinner outer insulation
Additionally, we are considering using upgraded GT3 timing belts for the MAX bots, as they are designed to carry larger loads, and would stretch less over such lengths.
Software to support MAX beds
In addition to making the hardware reliable, it is a top priority for us to continue building software features that make configuring a FarmBot fast and easy. The recent plant groups and grid/row planting features were a huge help in reducing tedious/repetitive tasks associated with managing hundreds of plants, and we expect to continue improving the farm designer and other built-in features to improve the experience.
6 Likes
Hey @roryaronson in the video add it showed changes to the Farmduino, could you comment more on those changes?
Sure thing 
We have two new electronics boards coming:
- A new Farmduino that will be in all of the Genesis, Genesis XL, and Genesis MAX v1.5 kits
- A smaller, simplified board dubbed Farmduino Express that will be in all of the Express, Express XL, and Express MAX v1.0 kits.
Here’s what different from our past electronics:
Better drivers
Both of the boards feature integrated Trinamic TMC2130 stepper drivers controlled over SPI. These drivers provide significantly quieter operation, can provide more current to the motors, and because they are mounted to the main board instead of small carrier boards, the heat dissipation is better. The drivers also have built-in stall detection capabilities via back-emf sensing, which is critical for the Express kits because they won’t have rotary encoders. One last benefit is that all of the driver parameters (mode, microstepping, motor current, etc) can be adjusted via software instead of jumpers/DIP switches/potentiometer screws. We plan to expose the relevant parameters to users in the web app.
Real-time clocks
Current FarmBots that lose their internet connection will also quickly lose track of time because neither the Raspberry Pi nor our past electronics boards have real-time clocks. This has limited long-running offline functionality of the FarmBot. The new Farmduino Express board includes a real-time clock that communicates with the Pi Zero directly via the GPIO pin header connection. Because the Farmduino included with Genesis kits is connected to the Pi 3 over a USB cable, we opted to put a real-time clock on a new version of the Pi Adapter Board, which will communicate directly with that Pi over GPIO as well.
Current-sensing peripherals
The new Farmduino (the one included with just the Genesis kits) has new circuitry allowing it to measure the load on each of the peripherals. We’re hoping this can be used to detect things like if a seed has been picked up by the seed injector needle or not, if the vacuum pump line is clogged, or if a peripheral is faulty. These are all somewhat speculative use cases though - we need to do further development and testing to see if those ideas come to fruition 
3 Likes
