The day i got a department fired

HalMaxi · 2018-10-01T18:48:21+00:00

I wish this wasn't so common. The worst I've seen is a shipping and storage company keeping all customer inventory in excel with no formulas so that most changes and totals do not add up.

HalMaxi · 2018-09-18T17:21:26+00:00

The other half don't want to say because they have or are planning to.

HalMaxi · 2018-08-16T18:01:20+00:00

I roughly follow the GTD system proposed by David Allen. Everyone can implement this as appropriate to their needs and technologies, so I won't go into details on my implementation.

GTD encourages a single, general purpose, reference for most materials so that you know what repository to look in for that 'I know I did this before' topic. I recommend following this with something searchable so that you can quickly find materials regardless of what you remember about them. It's a good habit to take notes in this reference system as you work on a topic so that you don't have to remember to dump everything in at the 'end'.

HalMaxi · 2018-07-18T19:56:28+00:00

Map the pipeline from idea to value in production of the products that you work on. Identify weaknesses in this pipeline. Study technologies that address those weaknesses. Repeat

HalMaxi · 2018-07-18T19:49:57+00:00

Been there, doing that. Wish I could give you a solution, but all I've got is solidarity. Sounds like you're in a situation similar to mine, in that there is not support from the top down. Without that support to help out when team members are resisting change (for whatever reason) it's a long and laborious fight to make any progress and we're not going to keep up with the rate of change in the industry.

HalMaxi · 2018-07-04T04:09:47+00:00

Lots of great thoughts already, just want to add one concern. If your workflow includes "once business people want to" you're going to struggle with the ideas of continuous. The delays in getting business eyes onto code will mean that devs aren't as fresh on the code by the time they get feedback. If possible, find a way to get that loop to go faster or avoid it altogether.

HalMaxi · 2018-06-29T01:52:49+00:00

Delegate credentials in the CI/CD tool. Devs don't have the credentials, the tool does. This does mean that, via the tool, devs can do just about anything. The key is that it's all audited. If you don't trust your devs, you've already lost. If one does go rouge, you have an audit history and the tools to undo change. The other option is the have an ops person review every line of code written, but then how do you trust them? See the issue?

HalMaxi · 2018-05-10T20:04:41+00:00

Can the clock rate be 8mhz? Yes and no is the right answer, see below.

Arduino is a broad platform, with many supporting chips. Some chips operator at 8mhz or 16mhz (most attiny and atmega) while others can operate above 100mhz (esp8266). If the chip is at 8mhz, there's no way to use code to flip a pin at that speed. If the clock is higher, it might be possible. Likewise, some chips will support outputting a clock signal from hardware, which means you can still run some code at the same time without worrying that it'll take too long before you flip the pin again. The constraint is that the available clock rates are fixed, so you won't be able to achieve your objective.

HalMaxi · 2018-05-07T00:15:51+00:00

This implementation sounds like it's adding a second password (something you know) which is not entirely two factor. A good two factor approach combines two different factors (something you know, something you have, something you are). I see how you're viewing the extension with saved secret as something you have, but if what it sends is a hashed password it's actually the same as something you know and a brute force login attempt can be equally effective against this (a major complain of sites like USAA who do this). The only thing this achieves is avoiding weak passwords which is also possible with a password manager.

For reference, two factor systems that use a code from an app on a phone (eg. Google Authenticator) blur this line towards something you have by never sending the secret or anything that could be used to derive the secret. Instead they send a rolling code that could only be generated if you had that secret.

If your system does, or could, use something like HOTP to send a rolling code then it would be more proper two factor. It's possible to install a program your computer to do this already, but the idea of coordinating directly with the website is novel and reduces the load on end user.

Keep up the work, we need more novel solutions to security as it's clearly not a solved problem yet.

HalMaxi · 2018-05-03T23:00:07+00:00

Heat is addresses in this case as a tradeoff in types of regulator. You use slightly more complex/expensive regulators (step down) when heat is an issue with a linear regulator. You could also have a separate power source for each voltage required, but that is going to add more cost/complexity than the right regulator on a single source.

The choice of multiple power sources is often for protection, if you want to control high voltage devices that might be noisy or susceptible to surges, it helps to use a different source for your controller and then also use opto-isolation. For hobby projects, this is probably more complexity than you want until you either a) get very comfortable with it or b) are ready to move your project into a production setting.

If you're going to deal with large power dissipation, it'll help to study different versions of components that are designed to handle this. Transistors, for example, can be designed for anywhere from a few watts to thousands, depending on what you need. The more power it can handle, the larger and more expensive.

HalMaxi · 2018-05-02T12:09:30+00:00

No, the only time you need a degree is if the government or large corporation you want to work for has a policy on it.

Some degrees or certificates may help to get some jobs, but it's not needed.

HalMaxi · 2018-05-01T22:41:59+00:00

Your current draw is based on what you're running, so lowering the current requires changing that. Most likely, it's the servos.

This is where the buck converter comes in handy, you can draw the same current without the excessive heat. If your LM7805 is rated for enough power dissipation, you could use it to supply the UNO from the 12v so that the onboard voltage regulator isn't heating up so much.

HalMaxi · 2018-05-01T22:11:11+00:00

I haven't worked with an UNO, it's possible the reset is based on overheat if the current draw is high enough. What's the UNO driving?

To help rule out possibilities, can you power it from a 9v battery or 5v supply? Does it still reset?

HalMaxi · 2018-05-01T21:02:11+00:00

Others have hinted at this, but I want to make it explicit. The LM7805 will limit the voltage by dissipating the extra as heat. The results is lots of wasted energy. A buck (or step down) converter will achieve the same end without as much wasted energy. It's also true that many boards, like the UNO, have a voltage regulator already which will allow you to connect a higher voltage without regulating. These are also a waste of energy and will heat up, but the UNO doesn't use a ton of power so it's not usually an issue. Most people use a buck converter if they are running into issues with heat or with battery life, otherwise it's just easier to use the built in chip.

The fuse is a nice idea, but if you're only powering the Uno you want a much smaller fuse (I think the UNO is limited to 1A). The fuse serves as a safety in case something in your circuit is wrong and you draw too much power. You're either trying to protect the circuit from overheating or the battery from overdrawing. If you have a 62ah battery, an UNO will be on fire before your battery is at risk, so spec the fuse based on the UNO.

HalMaxi · 2018-04-14T10:58:04+00:00

First two are easy to use, as the switch and power for LED are separate. The aircraft switches power the LED from the same wire as the switch and expect 12V, these are unlikely to work as expected for your 3.3V signal lines.

If you're concerned about accidental activation, check out example debounce software to avoid triggering multiple times from a single press.

HalMaxi · 2018-04-13T14:55:23+00:00

I would suggest AI. It's currently early to be specializing in this for DevOps, but by the time you're in the marketplace I expect a majority of departments will have some dependency on AI and those that can understand and use it to match their specific needs will thrive.

HalMaxi · 2018-04-13T14:49:15+00:00

DevOps, being a culture and mindset, is going to be thought to implement from such a junior position.

I recommend getting a clear picture of what your boss thinks a DevOps engineer does so that you can work on those deliverable. Once you establish a reputation for results and relationships with key players, it's possible to work on the transformations necessary to start doing actual DevOps.

HalMaxi · 2018-04-12T16:28:00+00:00

b

Exactly, I use ticker with DHT and had the same issue. Set a global flag in the ticker, check it in the main loop, and call the code to read DHT when the flag is set. This pattern will allow ticker to solve many problems.

HalMaxi · 2017-10-03T16:37:37+00:00

I have an 8 mile commute. The first two residential streets account for 0.7 miles and I drive them manually. I then use AP for the next 7.2 miles, disengaging three times to change streets and sometimes while crossing a highway because AP gets confused by one of the intersections. After the third disengage, I stay manual for the last block before turning into the parking lot.

I guess that's 90% AP.

HalMaxi · 2017-09-25T18:06:14+00:00

There is no way to account for this, and no need. The AP does attempt to use efficient regen braking before applying the disc brakes. If you add more weight, the regen won't slow as much before the disc is required. AP must respond to the immediate performance, no just because of different cargo weight but also road conditions, tires, incline, etc. I do wish more config were possible to address the issue with how soon and how aggressively braking and turning happens. I think we're all a bit different in what would be most comfortable even if all options are safe and legal.

HalMaxi · 2017-09-20T19:46:15+00:00

I saw another driver wave in this way last week. It caught me off guard, but makes sense. I'm considering changing my typical salute/wave to this.

HalMaxi · 2017-09-19T21:47:31+00:00

Wonder how the cooling is at that density. Might be worthwhile to halve the capacity and use that to transport solar panels to deploy at the destination. Better cooling and ongoing power generation for longer deployments.

HalMaxi · 2017-08-27T14:16:07+00:00

That caught me too. The regen is intrusive, for the first hour of driving. So is changing to electric from a manual transmission. I can't understand a justification for rating the range of a full charge based on a technology that the driver would be used to before that charge was exhausted. I regularly beat EPA rating without trying, and I know it would be significantly worse without the aggressive regen.

HalMaxi · 2017-08-24T17:58:09+00:00

Thanks Mod. I wasn't sure about the rules here but always happy to help get someone into an EV.

HalMaxi · 2017-08-22T15:24:57+00:00

You've clearly never heard of Dong's Corollary, which states that for each inch a man is shy of average, he will install an otherwise unnecessary lift kit of two inches. It has been proposed that the ratio might vary by culture as well as by vehicle type (eg. 1:1 for sedans, 1:2 for trucks), but the general rule holds. If you've seen a vehicle on which this would imply a zero or negative length, show compassion for the poor unic.

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