- 07/24/2017 at 06:35 • 0 comments
07/13/2017 at 07:54 •
This is a follow up post to Stick Shift Lego Monster Truck
Last Month Hackaday had a post for "Converting a Robotic Motor For Lego Blocks",
and I happen to be building a Lego Monster Truck and I need a good way to power steering my vehicle. So I followed the instructions in the above post. But it turns out it requires more hand craft skill than I thought, and I don't have the 4.8 mm drill bit either, thanks to the imperial systems (The closest one I have is 3/16 inch, but I couldn't make it to work).
Fortunately, since I only control the gear box on one side, I found another way to hack:
2) Use a 5/64 inch drill bit to drill a hole on one end of a Lego axle, as illustrated below. For the Lego axle, find the end that has a small dip, which is easy to position your drill bit.
3) The DC motor has two axle heads, with one on each side. One of the axle head is tied to a gear inside the yellow gearbox, so there is not much you can do unless you open the yellow gear box. But the other axle head can be pulled out without opening the yellow gear box. And that one is attached to a metal axle with a seesaw head. Plug the reworked Lego axle from (2) into the metal axle, and you get yourself something that can be used to drive the Lego gear box
4) Use PWM to control the motor, which will drive the Lego gear box (shown below before motor is mounted). Now my Lego monster truck can make turns left and right!
PS: ways to mount the dollar motor
There are many ways to mount the motor onto the Lego bricks. I simply use cable ties to attach the motor firmly to the Lego gearbox.
But you can also stick a 2 x 4 plates (with holes in the middle) to the motor.
Or you can use a Lego compatible DC motor support from the following
(The motor in the following is NOT the same as the one I hacked)
07/10/2017 at 07:15 •
My daughter was pouting her lips last week because she found out her Lego bricks were stolen by her daddy. Fortunately, I'm now able to make it up by giving her something better.
The Lego Monster Truck you see in the following video is a demonstration of PulseRain M10's capability. It uses one PulseRain M10 board, one PWM shield and one ESP8266 shield. Both shields are from Sparkfun.
This monster trunk has two DC motors. One is for driving while the other is for steering. Most Wifi Robot cars on the market are using 4 wheel drive or 2+ 1 (Two wheels plus one caster). With 4 wheels or 2+1, the designers can avoid dealing with the steering mechanism. And to make turns, those cars will spin the wheels on each side in opposite direction. However, the drawback of such design is that each driving wheel was pushed by a separate DC motor. And no two DC motors are the same, especially for cheap ones used by toy. This makes it hard for those cars to go straight lines.
Of course, those can be fixed by:
(1) Manual calibration, where a potentiometer (or something with similar nature) can be used to keep the two DC motors spin the same way
(2) Use better motors and better control mechanism. Instead of using open loop, a close loop control can be adopted. However, close loop requires a sensor (such as speed, position etc) for feedback. Those will just make things a lot complicated or more expensive.
The Lego Monster Truck shown below takes a different approach. It uses Lego gears and beams for steering. To make it happen, I made a hack to one of the DC motor and the Lego axle (more to follow on this part) so that the motor can work with a Lego gear box.
For driving force, another DC motor was used to drive two wheels with one axle. In this way, no need to worry about any mismatch of motors.
And to control the truck, I chose a retro style joystick that is compatible with Atari 2600 . Yes, this is a stick shift vehicle :-) For hardware building instructions, please go to http://limerick.pulserain.com/2017/07/how-to-build-lego-monster-truck.html . For firmware and host software, please go to https://github.com/PulseRain/Lego_Monster_Truck .
Now, without further ado, Let me give you the Lego Monster Truck:
06/13/2017 at 06:29 •
Got ESP8266 Wifi Shield from Sparkfun. Initially I thought I need to replace the DC Power Jack with a low profile one. But now it seems that is unnecessary :-)
- 05/01/2017 at 01:09 • 0 comments
04/30/2017 at 06:11 •
The BOM of this project has also been uploaded to findchips.com to streamline the supply chain. The good news is findchips.com is a very handy tool to gauge the BOM cost and available stocks. The bad news is that we've just found the microSD socket in the current BOM (SCHD3A0100) is obsolete. Fortunately, we have found a pin compatible part from Molex (47219-2001)
04/30/2017 at 04:50 •
Being a HackadayPrize2017 entry, one of the obligations is to "document all open source licenses and permissions as well as any applicable third party licenses/restrictions". To fulfill this obligation, a file named "PulseRain M10 Designs – License Agreement" has been uploaded into the FILES area of this project.
In a nutshell,
- The PCB portion of the PulseRain M10 Designs, as defined in the license agreement, are licensed under the terms and conditions set forth in Creative Commons Attribute-ShareAlike 3.0 United States.
- The FPGA portion of the PulseRain M10 Designs, as defined in the license agreement, are licensed under the terms and conditions set forth in GNU Public License Version 3 (GPLv3). And for those who want to use the FPGA portion of the PulseRain M10 Designs in ways that are incompatible with GPLv3, PulseRain Technology LLC. offers commercial licenses instead.
- The firmware portion of the PulseRain M10 Designs, as defined in the license agreement, are licensed under the terms and conditions set forth in GNU Lesser General Public License Version 3 (LGPLv3).
- The software portion of the PulseRain M10 Designs, as defined in the license agreement, are licensed under the terms and conditions set forth in Apache License Version 2.0
But please do look at the fine print, as that's the official license agreement that carries legal weight.
04/23/2017 at 22:14 •
The initial test on pilot run boards runs ok. And the V1.0 schematic and layout files are now released under
And the design was made with Eagle CAD 7.7
04/23/2017 at 06:59 •
Finally, the pilot run for production has come back! All the protruded components in V0.9 has been realigned so that the production version will have a smooth edge on all 4 sides. And standoffs and washers are also added, as illustrated below:
- 03/31/2017 at 07:53 • 0 comments