March 26th update

KESbot working better now. Space invaders Nerf firing gun working well under manual and remote control

Sorted out a problem with the Hubble challenge code that would not run.

We found an interesting issue with the yellow geared motors which have a shaft out of each side. One side drives the wheels well but the other side slips frequently under load. Took a motor apart to identify the issue, and ended up reversing two of the motors to use the other shaft, and then had to swap over the connections as the motors ran the other way round.

A bit of final tweaking and we should be ready for Saturday. Minibus is ready and the boys are looking forward to the event.



March 12th update

Back at robot club after 2 weeks half term and 2 other weeks off, due to staff shortages to run the club.

Good progress made on the nerf dart shooter – making use of the school’s new 3D printer.

The wooden block is the cartridge that holds the nerf darts. nerfshooterThe 2 orange disks spin in opposite directions and when a dart is pushed out through the bottom of the cartridge by a servo at the back it is grabbed by the two wheels and shoots out forwards. We still have to mount it and finish off the servo, but even with just 3 volts on the motors, the dart comes out at a good speed.

Countering our progress on this area the PI 3b that were using for developing the camera code for the Hubble challenge has died on us. Fortunately we have one more that we can use, but if we have many more processor board failures it will slow down our consolidation of the different programs onto the robot we are bringing to Pi Wars.

We have python programs for all the challenges but we need a bit more work on some of these to get them to the state we would like. Hopefully the couple of weeks we have left will do that.

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Feb 5th Update

Slow but steady progress again

We have added the rest of the sensors to the revised chassis and it now looks like this.


Still plenty of work to do on the coding, but we now have some better ideas for our Nerf bullet firing mechanism and have done some experiments that show that 2 spinning wheels going in opposite directions can propel the Nerf bullet quite quickly.

The updated NOOBS 3 is now working Ok with the camera, so at least that is one problem solved but we do still need to recreate some of the code we lost when the SD card failed.

The next couple of weeks there will be no club as it is half term then staff meetings but we hope to get started again on March 5th, which does not give us long to finish everything off before the competition at the end off the month, but we usually manage to pull it all together just before the end.

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22nd January update

Two useful steps forward this week, and one back.

1 – We hooked up the remote control program with the motor driving program and managed to get some motor control from the joystick on the gamepad. It is not working quite as expected, but with a bit of debugging we should have our remote control sorted out.

2 – Following a very useful contact with another group we now have the basis for the design for our Nerf bullet firing mechanism for the space invaders challenge. It uses 2 spinning disks to spit out the Nerf bullet.

One step back – the Micro SD card being used by the developers of the camera based Hubble challenge has suddenly failed, wiping out all their latest code. At least we still have the ideas being used and the programmer thinks he can recreate it fairly quickly. A salutary lesson for all developers about keeping backups – but in my experience people never learn the lesson until they lose something major for the first time.

The alternative chassis is nearly ready, so after a few tests we will have to decide whether to go with this one as our prime robot, or stick with the less powerful one we have been using so far


January 15th update

Back after the Christmas break

Spent quite a while diagnosing problems with the 10 inch HDMI monitors we have been given access to . It appears that they do not work with the supplied power adaptors when connected to Raspberry Pi zeros. They only work if we drive them via USB cables from USB ports on the school PCs, Which means that we can’t use them in the workshop as there are no PCS in there.

On a more positive note, we got the line following sensors wired up and talking to the line follower code, but need to do a bit more debugging to get the program working as required. We also managed to drive the pi zero successfully from the Poundland mobile phone backup battery device which gives an adequate 5v USB output from the internal 3.7v LIPO battery. Motor power is currently 6xAA batteries giving 9 volts, but we do have some 2 and 3 cell LIPO batteries available as well.

The chassis team have done some more design for our alternative chassis which will hold the motors more securely. We will build a robot on each chassis and see which works best.

The remote controller team have got most of the buttons on the gamepad being recognised by the program, so we need to link this up with the motor control program now to complete the remote control setup.

Dec 11th Update

Slow progress this week and not so much to report. We have continuing problems with the small HD monitors we have access to. We had 2 of the 10 working last week but none this week.

We did speed trials between the mark1 chassis (2 motors driving 4 wheels) and the mark2 chassis (4 individual motors each driving one wheel) and found that the mark 2 is a lot faster on the same 6 volt supply, so we are likely to go with that for the competition robot.

The space invaders team have fabricated a cartridge to hold and deliver the Nerf gun darts but haven’t finalised the rest of the design yet.

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