Meanwhile, today I need to finish getting the electronics back up and running again with the new longer cables that will facilitate mounting the electronics on the wooden backplane that the ME guys are constructing. Hopefully they will bring it by around mid-afternoon today and we can mount all the boards on it and re-test.
I'm going to disconnect the +3.3V supply from the DE3 board to the GPS module to prevent unintentional back-powering of the DE3 from the GPS. (Of course, I'll leave the grounds connected, however, since a common ground reference is a necessity in any event.) OK that's done. Even though the +5V supplies are still connected, the lights on the DE3 don't turn on when the only back-powering is through that one.
Note to self: Remember to re-burn Wi-Fi with INFO-mode condition reporting turned back off. Let me go ahead and do that now so I don't forget. OK, did that, and for the FEDM's Wi-Fi as well.
It occurred to me to stick a gender-bender in the FEDM's DE9 port and stick M-M double-ended header pins in there; wiring to that instead of the thicker DE9 pins will avoid damaging our jumper wires. However, the thinner pins have a tendency to pop out of the F DE9 connector. So, not sure if this will really be a good solution....
Derp, I just realized that the reason the GPS hasn't been receiving any satellites the last couple of days is because I never plugged its antenna cable back in! OK, that's fixed now.
Fixed a few bugs in some new server code that only got exercised after the GPS was working...
The ME guys are here now with the backplane. They left briefly to get a drill. The plan is, we'll mount the electronics on their board this evening before I leave, and they'll finish up the cover tonight and mount it tomorrow. Samad is on his way with his power board.
As of right now (4:40 pm), the recent server changes to automatically start the run after the CTU and FEDM are both ready and the GPS time is good appears to be working. Currently doing a run collecting actual absolute-time-referenced data.
Also good news: My new, longer interconnect cables seem to be working more reliably than the previous cables; I no longer need the separate breadboard that I was using before to wire all the grounds together. Here is a photo of the present desktop setup:
Samad is here with a newly resoldered board to fix his via issues. He still needs to solder the capacitors and make a new cable to power the DE3 board. I asked him to do a negative continuity test, and once that's done we can test his board under power from the ATX supply to make sure we get the right voltages on all of the outputs. Then after he makes his DE3 cable, we need to test the voltage levels at the end of that before we plug it into the DE3 board. Then, and only then, can we try using his board to power the DE3 and the other boards in the system.
The ME guys can drill Samad's board tonight before everyone leaves, and then Samad can go home and finish the soldering he needs to do. I'm doubtful there will be enough time for us to test it thoroughly before the Design Fair. If not, we can always power the GPS and CTU's WiFi via USB (as we are doing now) temporarily. (In any event, we will probably be forced to power the detectors through their wall-plug supplies, since no one has made long power cables for them yet.)
As soon as the ME guys get back, we need to work on mounting the electronics to the backplane.
The ME guys were away quite a bit longer than I expected. While hanging around waiting for them to get back, I ran out of other more useful things to do, so I started working on cleaning up my desk drawer.
After they finally got back, they finished drilling needed holes on the backplane and I helped them mount all of the PCBs on it and reconnect all of the electronics. (George took a photo of the mostly-finished assembly to use in the presentation, but I did not get a chance to take one of my own yet.) We re-tested the electronics (with the new cooling fan) and everything still worked except for the GPS, which was stubbornly refusing to acquire any satellites again. The antenna was connected this time, so that's not the problem; we could try to blame high-altitude haze (making a ring around the moon) or simple bad luck in terms of the number of satellites in the portion of sky visible from the windowsill. The server is already automatically trying all of the commands (resets, setting date & time) that I know of that might help with acquisition. There's not much else we can do, except for cross our fingers and hope that enough satellites will be visible from the lawn between the Engineering building, or wherever our GPS antenna ends up tomorrow (depending on exactly where we set up). Regardless of whether the GPS is really acquiring accurate times, we can still demonstrate the rest of the system tomorrow; it just requires typing a manual "HOST START" command to the CTU (since the automatic startup waits for the GPS to be ready).
When I finally left (at about 8:30 pm) the ME students were starting work on setting up the support structure for the new Peltier cooler and cooling fan. Hopefully they will finish getting the new cooling system all assembled before tomorrow. Maybe they will also mount the cover, but if not, it can always be attached later, at the Design Fair or afterwards - that is an easy part. I am planning to come by to pick up all the equipment at around 9:00 am and load it into my van to take it over to ECE. I will be busy with general design fair preparations at ECE from 10-noon, and am planning to start physically setting up tables, power cords, etc. around noon.
I'm planning to swing by Loewe's in the morning and pick up some non-tacky tape for taping cables to the floor, and maybe a new extra extension cords and power strips.
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| COSMICi electronics; final test before mounting on backplane. Everything is working. (FEDM PLL still @ 300 MHz, though.) |
Samad is here with a newly resoldered board to fix his via issues. He still needs to solder the capacitors and make a new cable to power the DE3 board. I asked him to do a negative continuity test, and once that's done we can test his board under power from the ATX supply to make sure we get the right voltages on all of the outputs. Then after he makes his DE3 cable, we need to test the voltage levels at the end of that before we plug it into the DE3 board. Then, and only then, can we try using his board to power the DE3 and the other boards in the system.
The ME guys can drill Samad's board tonight before everyone leaves, and then Samad can go home and finish the soldering he needs to do. I'm doubtful there will be enough time for us to test it thoroughly before the Design Fair. If not, we can always power the GPS and CTU's WiFi via USB (as we are doing now) temporarily. (In any event, we will probably be forced to power the detectors through their wall-plug supplies, since no one has made long power cables for them yet.)
As soon as the ME guys get back, we need to work on mounting the electronics to the backplane.
* * *
The ME guys were away quite a bit longer than I expected. While hanging around waiting for them to get back, I ran out of other more useful things to do, so I started working on cleaning up my desk drawer.
After they finally got back, they finished drilling needed holes on the backplane and I helped them mount all of the PCBs on it and reconnect all of the electronics. (George took a photo of the mostly-finished assembly to use in the presentation, but I did not get a chance to take one of my own yet.) We re-tested the electronics (with the new cooling fan) and everything still worked except for the GPS, which was stubbornly refusing to acquire any satellites again. The antenna was connected this time, so that's not the problem; we could try to blame high-altitude haze (making a ring around the moon) or simple bad luck in terms of the number of satellites in the portion of sky visible from the windowsill. The server is already automatically trying all of the commands (resets, setting date & time) that I know of that might help with acquisition. There's not much else we can do, except for cross our fingers and hope that enough satellites will be visible from the lawn between the Engineering building, or wherever our GPS antenna ends up tomorrow (depending on exactly where we set up). Regardless of whether the GPS is really acquiring accurate times, we can still demonstrate the rest of the system tomorrow; it just requires typing a manual "HOST START" command to the CTU (since the automatic startup waits for the GPS to be ready).
When I finally left (at about 8:30 pm) the ME students were starting work on setting up the support structure for the new Peltier cooler and cooling fan. Hopefully they will finish getting the new cooling system all assembled before tomorrow. Maybe they will also mount the cover, but if not, it can always be attached later, at the Design Fair or afterwards - that is an easy part. I am planning to come by to pick up all the equipment at around 9:00 am and load it into my van to take it over to ECE. I will be busy with general design fair preparations at ECE from 10-noon, and am planning to start physically setting up tables, power cords, etc. around noon.
I'm planning to swing by Loewe's in the morning and pick up some non-tacky tape for taping cables to the floor, and maybe a new extra extension cords and power strips.
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