Tag Archives: Robots

I got to meet ASIMO at the Honda HQ in Slough.

I got to meet ASIMO at the Honda HQ in Slough. They demonstrated his ability to walk dynamically (i.e. not balancing on a single leg between steps), to run (very impressive), to kick a football, deliver a tray of drinks, face tracking and of course … dance.

According to the guy I spoke to after the event, for that demo, ASIMO had a map of the floor, and the operator was giving him commands to walk from X to Y. The number of steps and the direction, joint control, etc, was then all executed autonomously in ASIMO. This particular model didn’t have sonar, so didn’t have obstacle avoidance, but others do. Same for climbing stairs, the command is given to climb the stairs, then ASIMO calculates the position and joint control autonomously.

Although ASIMO is not truly autonomous, the level of processing is amazing and the aesthetics and design really make you feel relaxed with a robot. You feel compassion for it. I almost felt sorry for it, being made to perform. 🙂 However, the employees who manage ASIMO and careful to refer to ASIMO as an “it” not a “him” or a “her”. Apparently its not a boy or a girl. However, the French member of staff I spoke to, told me there is no French word for “it” and “robot” is a masculine noun, so for him, ASIMO is always little boy ! 🙂

ASIMO at the Honda HQ in Slough - 21 Oct 2014

ASIMO at the Honda HQ in Slough – 21 Oct 2014

ASIMO at the Honda HQ in Slough - 21 Oct 2014

ASIMO at the Honda HQ in Slough – 21 Oct 2014

The Cubli – A balancing, jumping, walking robot cube !

I found this online. A robot developed at ETH Zurich. It is brilliant and beautiful. I had to share …

AVC – 2014 Report

The Sparkfun Autonomous Vehicle Competition this year was lots of fun, as usual. I ran a similar setup to last year, with the same chassis, mBed microcontroller, Magnetometer & GPS. The only difference was a new controller PCB with some extra features, and some changes in the code. The new control board has some incremental improvements from last year, with on-board battery monitor, better layout, built in Mux to multiplex RC and Autonomous control, and an on-board RS232-TLL converter (MAX3221).

AVC 2014 controller PCB v3.2

AVC 2014 controller PCB v3.2

 

AVC 2014 controller board v3.2

AVC 2014 controller board v3.2

The battery monitor uses a shift register to control the 8 LEDs, so I only need 4 IO lines to control 8 LEDs. The mux uses a 74S157D to multiplex the PWM lines from the RC receiver and mBed out to the RC car steering servo and speed controller. By changing the mux select line, I can control the RC car from the RC controller or the mBed, either forced with a jumper (RC_SEL) or by using channel 3 on my RC transmitter. To decode the channel 3 signal and give me a digital output I use a Pololu RC Switch with Digital Output.

The other useful addition was a 1F super capacitor, attached to the vBAT pin on the mBed. One problem from last year was that all my log files were dated “1/1/1970” as when the mBed boots the clock isn’t set, and I create the log file on boot. I set the clock once I have a GPS lock, with the time from the GPS, but until I have GPS lock, I don’t know what the time is. The mBed has a real time clock, I just need to keep it powered between power downs.

Supplying 3.3v to vBAT keeps the RTC running, even when the main power is off. Usually, you would use a small lithium coil cell, but I had just bought some super caps to play with and they seemed perfect. I used a diode and resistor from the 3.3v power rail to charge the super cap while the power is on and limit the charge current. It works perfectly and kept the clock running for days while the main power was discounted. Now, all my log files have the correct date and time, and once I get a good GPS lock, I reset the RTC, just in case it has drifted.

The bot was ready a couple of weeks before the competition, but as usual, I didn’t have time to do much testing, and my flight only got in to Boulder the night before the competition, so I couldn’t spend the day before at the course. The day of the competition arrived and I got there early to setup and do some last minute testing.

I was in group 7 of the Peloton class. Team : “Mostly Robots”. Robot : “Eleanor”.

There are 3 heats (3 attempts at the course). The are timed, with bonus points for navigating obstacles.

AVC Ground Course ((c) Sparkfun)

AVC Ground Course ((c) Sparkfun)

Heat 1

Heat 1 got off to a good start.  I’m always apprehensive as the bot approaches the first corner. Anyone can build a bot that just drives in a straight line and crashes in to the fence. Turning at the first corner autonomously is a good feeling ! 🙂 The bot was swerving badly on the straight, more than last year. Same old magnetometer issues from last year, but it turned perfectly on the 1st corner. Its programmed to avoid the barrels and zig-zag through them, which it did, and made the 2nd corner. However on the 3rd straight it started to wobble more and zig-zag quite badly instead of driving in a straight line. It made the 3rd corner, but then started to get a bit confused. It spun round in circles a couple of times, then crashed in to a bollard. Disappointing, but not bad for a first run.

AVC 2014 - Heat 1 GPS log

AVC 2014 – Heat 1 GPS log

Heat 2

The less said about heat 2 the better :-). It all went wrong, and straight off the start line the bot crashed in the kerb.

Heat 3

Heat 3 started well, the bot made the 1st corner, avoided the barrels and made the 2nd corner. But on the back straight got confused again and crashed in to the kerb.

AVC 2014 - Heat 3 GPS log

AVC 2014 – Heat 3 GPS log

In the end, a fun but disappointing day, as I know the bot can navigate autonomously, as it makes it round three quarters of the course, but the gremlins stopped me from completing all of the three heats.

I came 14th overall out of 25 in my class. Respectable, but I could have done better.

The problem is always the magnetometer. I need to find some time before the next event to work on fine tuning it and experimenting with some different positions to stop interference from the car’s motor and servos.

Roll on next year ! 🙂

 

AVC – All ready for AVC2014 next week

So, my bot is ready (ish) for this weekend. I have the new controller board installed. Only found 3 mistakes (and isolated ground, the wrong supply voltage on the RS232 header, and the SD card holder hasn’t soldered correctly.) everything else worked. I have fixed the first two, but I cant reflow the board again to fix the SD card holder, as I’ve already soldered all the plastic headers on. I can live without the SD card, I will use the internal flash disk on the mBed. It has a few restrictions, but I only store a waypoint file and a config file on it.

AVC 2014 Robot

AVC 2014 Robot

I’m running an updated version of last years code. But seeing as it worked last year, I’l stick with it and improve it slightly. Now I have a reliable xBee connection, the compass calibration process is much easier. No more cables. I will try this year to calibrate the compass, with the main motor running (albeit slowly) to ensure any interference from the motor is present in the calibration settings.

However, I’ve been so busy recently, that again I have not manage to complete a full outside test of the bot before getting on a plane for Boulder ! 😦 the first full test will be in the car park in the hotel the night before.

Not to self – find more time to tinker next year before the competition !

Wish me luck …

SMD PCB Stencils

Usually I build my printed circuit boards by hand. Once the boards are fabricated, I apply solder paste using the patented “Jon Toothpick Method”, then place the components by hand using tweezers. This works fine, as I usually only build 1 or 2 boards. But recently some of the projects I’ve been building have either lots of SMD devices (a recent board had 30+ 0603 resistors), or the devices I’m using are tin, with very small pitch legs (I use SSOP & TSSOP packages, which are very small).

So, I decided to try getting a solder stencil made to use during my next build. I use OSH Park for my PCBs and they recommended OSH Stencils. The stencils were very affordable. They cost about $10 each, and they are about 6.5 sq in. I think they are laser cut Kapton film which according to online review, is pretty durable.

The process of applying solder paste using a solder stencil is pretty simple:

  • Use a old PCB or a guide taped to a flat surface to stably locate the PCB
  • Place a PCB in the guide and line up the stencil with the pads on the PCB
  • Tape the stencil to the guide to locate it in place
  • squeeze a small bead of solder paste  across the film at one end and smear it across the film using an old credit card or squeegee.
  • The film shouldn’t have any left over solder paste on it after you make the pass across the board. The squeegee should wipe it off as it passes. Paste should only be in the holes in the film.
  • gently peel back the film off the board and the solder should be neatly applied to all your pads.
  • place components and reflow the solder in an oven.

Here are some pictures of the process.

AVC 2014 PCB

New PCB

PCB Stencil

PCB Stencil

PCB Stencil

Align stencil with PCB

PCB Stencil

Tape stencil in to position

PCB Stencil

Wipe solder paste across board

PCB Stencil - Solder paste

Solder paste applied on the pads

PCB Stencil - Solder paste

Solder paste applied on the pads

PCB Stencil - After soldering

After components and soldering

PCB Stencil - After soldering

After components and soldering

I’m very pleased with the results. There is almost no solder spilled on the PCB to clean off, you get consistently the right amount of solder paste on each pad  and the result looks very professional and neat.

The process was easy and quick. I think I’ll be using stencils with all my future PCB builds. I just need a pick and place robot now … 🙂

AVC – Round 1 video with on board camera

This is a video of my first fully autonomous round 1 attempt. I made the first corner and avoided two barrels, but then ran in to the inside fence. I don’t have any footage from the other rounds as my camera gave up shortly afterwards.

AVC – Outdoor testing video compilation

This is a video of the first few outdoor test runs of my AVC robot. As you can see, I had a lot of magnetometer issues, but eventually, the last run does make it to the waypoint, albeit a rather scenic route. 🙂