Every so often we spend the day taking things apart to see how the pros build things. We’ve collected phones, cameras, PDAs, and some other old electronics to see what’s inside.
The junk we get is too broken to be repaired economically so we learn from it.
We know we can’t fix this stuff but we respect it because it has given it’s life for us to learn…
Mr. Oliver and Mr. Ullrich are going to be assisting Mr. May while we’re gone on home assignment. Mr. Oliver is another hard core software engineer and the club has really enjoyed his passion. He’ll probably be leading the way forward with Linux and security skills. He’s also set up a wiki so that we can record our club activities in community. http://gchq.ajosoft.com/
There is always a vibrator motor in the cell phones and that means we can make vibrobots! We only had one toothbrush this time but that didn’t stop us…
Today we put the final touches on the submarine and then took it into the pool for the maiden voyage.
Everything worked as planned. The battery supplied enough power for the motors to really scoot this submarine along. Pitch and yaw were easily controlled by the three motors.
The pressure is on to get the submarine finished before we return to the States for Home Assignment.
Tuesday we did the second wet-test with an o-ring that I was finally able to find in town. The o-ring is a bit smaller than I had envisioned but it seems to work OK. We were able to weight test the submarine and cut some steel to balance and trim it.
Back in the lab we got the electronics put together and final tested with the small motors as the big motors were out at the machine shop getting new shaft extenders made.
Everything fits inside well and the conning tower motor assembly looks like it will work.
That was our complete day. Lot of work to get everything tested out.
Later, alone in the workshop I cut the right & left side motor mounts with a couple very mean drill bits. It was not the kind of thing that extra hands would have made easier.
On Saturday just a couple of us guys, David, Joshua, and I did the final wet-test for the final balance and trim of the sub. David was the scuba guy monitoring the balance tests in the water. I did the holding while he checked everything out.
Back in the lab we mounted all the motors and drilled holes thru the conning tower cover for the motor and tether wires. We tried to use the silicone adhesive to seal the assembly but it would not stick to the electrical wires. We used hot glue instead.
We caught a wiring mistake on the final motor test; the big motors all spun backwards and produced negative thrust. We rewired the heat sink / connector block so they run correctly.
The sub is now drying out and the hot glue is setting. Before club on Tuesday I’ll add an interior glue application to insure the wires are watertight.
We’re planning to be in the water live on Tuesday!!!
The electronics are done. We failed the wet test with a few leaks but we know where we want to go with that. We need an o-ring to make the final seal. All the other joints were watertight.
Taping the brass access plate - this is what didn’t seal and will need the o-ring.
Screwing on the brass access plate. This is the stern of the submarine. The empty tube section is the port side motor mount.
The only way to see if the submarine gets wet inside is to put it underwater for awhile.
Even with a small leak this is one happy crew…
Now on to finishing the electronics. Erica lead the team working on the big heat sink and parts inside the submarine. Richie lead the team working on the tether and control module.
Kwan actually spent the day doing some technical debugging of the hardest project we’ve done yet. She built a digital counter and one segment of the final LED didn’t work. We’ve messed around for weeks trying to find the problem. Today she systematically walked through the layout of the board, confirmed each part and connection was working, and finally tracked the problem down to a solder joint at a transistor. This was detailed work and she did very well. Best part - this project is finished and she can join the rest of the submarine gang.
If there was any doubt that this is not a ministry to MKs then this photo should put that thinking to rest…
What a great day we had today. Great feedback on how the club is meeting needs of this group of people. One person said with a big grin on his face, “this sure is a strange group of people.” I interpret this to mean that we’ve come together and have established a safe place for people to be themselves. After our time together I met one of the parents in the parking lot who said, “I’m not sure I understand all the technical details but we sure are talking about this stuff a lot.” I think this means we’re proud of what we are working on. These two things are exactly what our CreateSpace is all about.
We decided to do things a bit differently and focus entirely on the the Underwater UAV project. All the parts finally came in for the motor controllers and the caps for the submarine body.
Three groups were set up; one group worked on the submarine body, one group worked on the heat sink and parts inside the submarine, and one group worked on the tether and the remote control module.
Earlier in the week I spent time at home getting the final motor controller working with the real underwater motors. The only power supply I have that is big enough to power the motors is the car battery. So, the final design work was done under the hood of the car. Look at my happy face! Look at the spinning propeller on the front bumper!
So, we started working. I’m so bad at the camera that did’t get a single shot.
But, the sub is ready to wet test. The control module is starting to come together on the tether. The heat sink is drilled and the big transistors are placed on it. Everything is ready to integrate next week.
During the week, before I could blog, Jerry, a great friend and hardware engineer from the old days, gave me advice on a better power transistor for the motor controller. We’ll have to change out what we started but that should only take a few minutes.
School break and travels are over and we’re back to work.
Today was the first chance to get back to making the underwater ROV. As you can see we’ve setup with a 6 inch PVC pipe “T” with an extension. Richie is attaching the motor mounts with a spot of hot glue then the local version of silicone Liquid Nails. After the silicone cures the assembly will receive a sealed plexiglas front and top. Our access will be thru the bronze back screw-on access port.
We’re still struggling to get the motor controllers working. This has to become the high priority next task.
We did have a bit of a treat. Mr. Oliver did a bit of teaching on the ASCII table, binary and hex numbers, and the XOR function. We’ve got to learn a bit of hacking (well, perhaps software debugging) somewhere along the line! See how excited everyone is…
Kits are continuing. Gotta finish those up. Qwan’s kit is still giving us trouble and my replacement chip was completely dead. We’ll try getting replacement parts for that kit one more time.
The pollution monitor code is up and running and we’re successfully sending data to the net. Realtime pollution levels from the GIS Physics Room (the temporary site until our new pole is setup and CAT10 cable pulled. http://www.thaiconnections.org/cm-pollution-data
We continue to work on kits and are starting to see a couple finishing up – some successfully, some partially, some not quite…
Erica’s kit is the most fun. It is a remote control switch where you can preset the ON/OFF state of 5 devices and then toggle those states with a remote control unit. I’ll bet there is a way to control every device independently but we haven’t figured that part out yet. Originally, this was going to be used as the control unit for the submarine ROV. However two things are stopping us, first we can’t control the individual switches, and secondly Erica wants to take it home and turn it into a Christmas Tree Light Controller. Thankfully, Richie is also making one of these kits so we have another chance.
Honestly, there is another problem. I can’t get the motor controller circuit to work. I keep blowing up power supplies and amplifiers. I really don’t know what the issue is but this weekend I hope to get serious and finish this up. We really need it to move forward.
Another really cool kit that is almost working is Qwan’s digital counter. All the functions work but we’re fighting with one LED segment on the output. It’s a really nice build and I’d like to see her successful on this one.
In the not-working column is Caleb’s second VU meter that we tried to bias towards a second audio frequency range. Something is just not working reliably and it’s been a frustrating couple weeks. Noah, a new guy, keeps blowing up chips – which leads us to suspect there is a short somewhere in his board.
Nate was able to confirm full network functionality of the pollution monitor. We can FTP data to our web host thru the school firewall. We got data from the monitor. Now just to build a webpage. Next is to get the Arduino processor to integrate into the system which will make the whole thing a lot easier.
Our order of Arduino processors came in. This is a real advantage to be able to order them here in Thailand.
Lots of activity. Hopefully next week we’ll be working on pipe for the submarine – with working motor control circuits…
My camera died. No photos of the week’s work so only a narrative account…
Adrian Oliver, a friend and fellow (software) engineer, has committed to help out in the club when he is available. Adrian is the man behind PocketWeather (http://www.sbsh.net/weather-forecast-pocketweather). We’re proud to know him and his experience and passion is a great addition to the club!
Push forward on the kits. We’ve got to get them finished so we can start on the sub. The LED flashlight I picked up on the border was pretty much junk so I need to rebuild it completely. The plastic is nice but the electronics burned out as soon as it was powered up. Still a good deal – a 19 LED mirrored reflector and bezel for just 150 THB ($5). We could never make something this perfect ourselves, that is to say, we couldn’t make the plastic parts, we’re redoing the electrics…
We’ll give it one more week and then purchase our own big PVC pipe for the sub body. The school has some scraps but we might be moving faster than them. We’ll see. I demonstrated a simple, forward only, motor controller and purchased replacement motor controller chips for the two that we blew up testing the microcontroller. Hopefully, by the second week in October we’ll have some stuff ready to integrate on the bench. I’m really excited about the remote control project. That will be great if we can get it to work…
We got the pollution monitor FTP to log in successfully showing we can now get thru the school’s firewall. We were also able to remote control the PC so that is confirmed working as well. Need to commit more time on proving the file/data transfer so we can get this project really moving.
The older guys finished up two of the VU meters and tested them. Both worked fine. We started to try to adjust the input frequency response of one of the boards only to find we didn’t have the expected capacitors in the locker. Purchase task; one set of about 10 caps to experiment with… Chiang Mai has run out of waterproof LED strips. We’re ready to solder and we need them – NOW!
A quick retro post from before the international school year started…
Each year as the new students come in there is an opportunity to “sell” the extracurricular activities.
It’s always fun to see the excitement of the new kids and the anticipation of those just a bit too young for our club. I demonstrated last year ROV, a bunch of photos, and one of the “useless machines” that turn themselves off.
Everyone says we should do a public Science Fair like the old days. If this activity is any indication then there are a lot of people that would participate.
I’d love to be able to do a fair like this at the other schools in the city.
