tag:blogger.com,1999:blog-42430552063276898632024-03-04T22:29:41.047-08:00Nick's BlogNickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.comBlogger518125tag:blogger.com,1999:blog-4243055206327689863.post-51855522287256653342017-08-25T09:16:00.000-07:002017-08-25T09:16:03.573-07:00Things I've learned planning an eclipse vacationWe went to Salem, OR for the Great American Eclipse of 2017. We had a blast and the trip went really well, particularly because we made a lot of the right decisions. Here's what I've learned in preparation for a vacation to see a total solar eclipse:
Take the weather into account. The 2017 eclipse was in August, which meant clear skies could easily be predicted over most of the eclipse's path.Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-43145613341484647662015-05-02T08:44:00.001-07:002015-05-17T22:45:52.319-07:00On Tesla's PowerWallWhen you're a hammer, everything around you is a nail.
Tesla's in the energy storage business. That much is clear. Until now, they're couched it in the form of electric vehicles, but let's face it - there's very little to the drivetrain of an electric car. That's partially because electric propulsion is very nearly ideal for transportation - maximal torque at 0 RPM, a wide torque curve (so no Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-65083919886086978352015-04-13T06:55:00.000-07:002015-04-13T06:55:04.451-07:00The Blacklist: Statistics and The King FamilyOn a recent episode of the blacklist, the central plot device was centered around a bizarre family whose scion waged repeated battles to the death to secure their inheritance. These battles were in the form of auctions for illegal goods. Whichever brother secured for the family the fewer proceeds would be required to play one round of Russian Roulette.
The problem with this becomes immediately Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-53130911404039493892014-04-09T09:49:00.004-07:002014-04-09T09:49:54.155-07:00The mystique of trainsI thought of something interesting this morning.
There are obviously a substantial number of amateur automobile drivers here in the U.S. I mean that not as a slight, but in the dictionary sense of the word - people who drive but are not paid to do so. In fact, amateurs probably substantially outnumber the professionals given that nearly everyone over the minimum age has a driver's license.
Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-78334633776077576172013-12-11T10:59:00.001-08:002013-12-11T10:59:30.804-08:00First week with the VoltWe're around 10 days in, and we've had enough time now to form some general observations about the cost.
On the highway, as a pure hybrid, the volt gets around 32 mi/gal. Not bad, and that is a worst-case scenario for a hybrid. This really only impacts us when we go on a long trip, but it is almost 10 mi/gal better than the van, and 5 mi/gal better than the old Passat.
As a pure EV, we seem to Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com2tag:blogger.com,1999:blog-4243055206327689863.post-16116345014631046262013-12-10T22:40:00.000-08:002013-12-10T22:40:18.088-08:00What is the plural for "Hydra?"There are now two Hydras in the world.
We got my wife a Volt, so we are now a two EV family. And instead of installing a second charging station, I built us a Hydra. We spent a week moving the plug back and forth, but I was always nervous that I'd forget to charge one of the cars. And if it was the Blueberry, that would be a particular problem (that's our name for the Fit EV).
There were no Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-6837303700508146602013-12-08T11:31:00.000-08:002013-12-08T11:31:05.694-08:00Questionable consequencesI recently bought a toaster oven and immediately took it apart. It is now a surface mount reflow soldering oven, but that's been covered in detail elsewhere.
As I was cleaning stuff up in the garage, I ran across the instruction manual for it.
So what?
This little snippet caught my eye and made me chortle:
LOL. Or what, exactly?
I kind of get where they're coming from. The Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-85316462918216042852013-12-01T22:42:00.002-08:002013-12-13T12:20:12.926-08:00Alternative controller idea... all-in-one backpackIt occurred to me today... I've been trying to reduce the cost of the controller board by shrinking the board. And that works, but the most expensive component is the LCD display backpack.
That got me thinking... Is there room on the backpack form factor for both the backpack's display i2c adapter circuitry and the Toast-R-Reflow controller?
And, sure enough, there is.
The board price Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com2tag:blogger.com,1999:blog-4243055206327689863.post-47409152943627134922013-12-01T12:50:00.001-08:002013-12-01T12:55:56.620-08:00Scarlet's new Chevy VoltAnyone who lives in Santa Clara really ought to have an electric car. Santa Clara's municipal electric utility, Silicon Valley Power has maybe the cheapest rates in the entire state. The upper tier of 10.2 ¢/kW-hr equates to around $3.40 per gallon of gas equivalent. And, of course, an electric car is about 3 times more efficient than a gasoline car.
But unless you buy a Tesla, it's Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-2446076252735052312013-11-30T21:59:00.000-08:002013-11-30T21:59:57.705-08:00Blinky LED earringsGetting into SMD fabricating has really opened the doors to all sorts of new ideas.
My first attempt at a wearable was sort of inspired in part by FLORA and the other wearable stuff at AdaFruit.
It's a 1 inch diameter board with 8 SMD LEDs mounted equidistantly around the outer edge. Each is hooked up to a digital pin on an ATTiny84. There's also a micro-switch input to the controller and the Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-28742197106934153182013-11-29T17:44:00.004-08:002013-11-29T17:44:36.501-08:00Toast-R-Reflow: revised schematics
I've revised the schematics a bit. First, the power board:
There's no actual change to the circuit here, just improvements in the layout.
The controller:
The change here is that a bunch of passive components have been added to the thermocouple input. There is a 1M resistor from the negative pin to ground. I'm not 100% sure why, but it's what the data sheet recommends. The RC networkNickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com2tag:blogger.com,1999:blog-4243055206327689863.post-45060003376831627152013-11-28T19:52:00.000-08:002013-11-28T19:52:22.534-08:00Toast-R-Reflow: how-to summaryThis is intended to be a sort of "landing page" that summarizes the Toast-R-Reflow project. Now that you're here, you can do a deeper dive by checking out all of the posts here with the toast-r-reflow label.
The internet is full of folks who have made their own SMD reflow oven by hacking a toaster oven. I'm not the first, and certainly won't be the last. The reason you have to hack them at all Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com2tag:blogger.com,1999:blog-4243055206327689863.post-86814263594698659472013-11-28T14:30:00.001-08:002013-11-28T14:36:11.019-08:00Toast-R-Reflow: the bottom line
The power board is rated for 8 amps per channel. That limitation is a factor of two things - the traces on the power board that connect the oven's innards to the traics, and the ability of the triacs and heat sinks to dissipate heat. According to the data sheet of the BTA-20 triac, at 8 amps, it generates 10 watts of thermal power. The case-to-mounting-tab is rated at 2.1 °C/W. The heatsinkNickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-91917513245696764072013-11-28T13:42:00.002-08:002013-11-28T14:36:20.112-08:00Reflow oven safetyWhen converting a toaster oven or skillet into a reflow appliance, some thought must be given to safety. There are obvious safety precautions concerning line voltage and heat, but one you may not think about is the fact that you started with an appliance meant for treating human food.
Even if you use RoHS solder paste, the flux is nasty stuff and it vaporizes. You can count on it getting Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-91784615269109032692013-11-28T09:24:00.003-08:002013-11-28T14:36:29.132-08:00The SMD adventure begins in earnestOrdered my first bulk order of SMD parts from DigiKey last night. 0805 1/8W resistors are 10 cents a piece in single unit quantities (plus, like, $3 shipping), but a reel of 5000 of them is only $15. And for me, that's easily a lifetime supply.
I waited until now because I wanted to get some experience with the reflow oven before committing to it as the path forward.
I can now say with some Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-34264571829560706142013-11-27T00:57:00.000-08:002013-11-28T14:36:37.473-08:00Toast-R-Reflow: First successI got the power board installed in the oven without too much difficulty.
This is a picture of the mounting for the power board. I drilled 4 holes in the outer sheet metal enclosure. There was a blank spot near the top (the piece is shown here upside down) where there were no ventilation holes (you don't want to be able to accidentally poke something through a vent and touch a high-voltage Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-37481904832615851812013-11-26T18:51:00.001-08:002013-11-28T14:36:46.848-08:00Toast-R-Reflow: Initial successThe power board prototypes arrived today. I built one out and connected it up to the oven. It works perfectly.
I fed it with a 5 volt power supply and a 200 ohm resistor and it turned the elements on and off like a perfect light switch. I left it on long enough for the elements to glow red hot and then quickly unplugged everything and checked the triac heat sinks and they were cold. I've now gotNickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-49974985192076640882013-11-25T14:46:00.002-08:002013-11-25T14:47:38.603-08:00The irritating thing about hardware designBeing a software guy by nature, I'm used to very rapid design and implementation turnaround. You edit the source code, compile it, upload it, try it, find bugs, lather, rinse, repeat.
What's chafing my hide now that I'm doing hardware projects is that the turnaround time to get a PCB fabricated is 2 weeks.
All I can do in that 2 weeks is obsessively go over the design that I've already paid forNickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-36917070953491450202013-11-23T15:50:00.000-08:002013-11-28T14:37:00.757-08:00Toast-R-Reflow theory of operationIf anyone cares to know how the Toast-R-Reflow actually works, it goes something like this:
The power board consists of a pair of MOC3020 photo-triac drivers, each triggering the gate of a BTA20 high current triac. The MOC3020s are directly connected to a set of screw terminals intended to be run to the logic board, which will be expected to provide the correct driver voltage and current for theNickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-39153260684264508292013-11-23T09:45:00.000-08:002013-11-23T09:46:33.594-08:00I beat SparkFun! :)SparkFun sells a small board that will adapt a 6 and 10 pin AVR ISP connector to a breadboard. I had been using a special cable that I made with a 14 pin DIP IDP plug on one end and the 10 pin 2x5 IDP socket on the other end. That works because the DIP plug can split the center channel of a breadboard. But I do think that SparkFun's answer is a touch cleaner. What bugged me was the prospect of a Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-69232858779661086312013-11-20T19:22:00.000-08:002013-11-20T19:22:41.578-08:00Toast-R-Reflow timingI got a better thermocouple today, so I tried the timing test again.
This time, 20-150°C took 2:22. 150-225 took 2:34, then back down to 150 took 1:50. Cooling down from 150 took longer than I cared to time, but that doesn't really matter so much.
So that means rising up to Soak is at just under 1 degree per second. Rising up from Soak to Reflow happens at just under half a degree per second. Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-85199719794737193592013-11-17T20:15:00.000-08:002013-11-28T14:37:39.895-08:00Toast-R-Reflow schematicsHere are the schematics for the two boards that comprise the Toast-R-Reflow project.
This is the controller board. In the upper left corner is the thermocouple amplifier. Below that is the 5 volt power supply. The input jack is a standard 2.1mm barrel connector. The rest of the circuit is the micro controller and its I/O. In essence, the controller takes in the temperature from the Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-59009968330965668952013-11-17T10:56:00.000-08:002013-11-28T14:37:18.549-08:00Introducing... Toast-R-ReflowI've been really into microcontroller engineering of late. I've created the J1772 Hydra, and the EV Sim Mark II as well as a whole bunch of little experiments.
I attempted to build a surface-mount version of the EV Sim II, and hand soldering all of those tiny little parts was a painful exercise. I was going to give up on the idea, but I was turned on to the concept of reflow soldering.
In Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com1tag:blogger.com,1999:blog-4243055206327689863.post-44341893592124589092013-04-07T22:55:00.000-07:002013-04-07T23:35:57.976-07:00Enter the Honda Fit EVI've leased a 2013 Honda Fit EV.
I'm not really one for "green" thinking. I've said more than once that I think that most of the things that are supposed to be good for the planet are either foolishly costly or ineffective or both. But if you find a way to save me a dollar, you have my attention.
I've talked about this a bit of Facebook, but I think it's worth adding a bit here about the math.
A Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com0tag:blogger.com,1999:blog-4243055206327689863.post-56398459676824251742011-06-05T20:28:00.000-07:002011-06-05T22:47:04.408-07:00MikroTik RouterBoard: the ultimate networking swiss army knifeI've been on the hunt for a while now for a better router for the house. What I've wanted was the perfect marriage of cost, customizability, utility and ease of use. The features I've needed:1. Basic NAT and Firewall with uPnP or NAT-PMP2. DHCP client on WAN port, DHCP server on inside network3. IPv64. Dynamic DNS5. Uplink bandwidth prioritization / QoSThe closest I have come up to now has been Nickhttp://www.blogger.com/profile/10500722547077537044noreply@blogger.com2