3D Printed MacBook Pro fan vents!

Here’s a quickie for today…If you happen to have a newer model MacBook Pro, specifically the 16″ model – these ducts might help for heat dissipation. Whether you are gaming in bootcamp, or just run a hot workload, this should be a huge help. I designed and tested these, and they do work surprisingly great – so I just had to share.

In most MacBook Pro models, the heat exhaust vents downward, and then spreads in all directions. This captures the heat exhaust, and routes it away from the laptop (and from those the intake vents).

These are meant for stationary use, and have been temperature tested (PLA is fine). As you can see – even on a cooling mat the performance was better than expected. While I didn’t exactly test for exact temperatures, I did do rough temperature check during tough workloads and noticed a difference.

This may even work on other thin profile or ultrabook style laptops.

Don’t own a 3D printer? Reach out to amacfa@gmail.com and I’ll mail you two, just pay shipping!


Bitcoin energy myth, and the flaws of Proof of Stake

The myth Bitcoin uses too much energy

People often complain about Bitcoin’s energy use, and throw around useless metrics like cost per transaction. This metric is useless because Bitcoin uses almost all of it’s energy during the mining and minting process, and hardly any at all for day to day transactions. Also:

  • The energy spent is per block, which can have a varying number of transactions. More transactions does not mean more energy
  • The economic density of a Bitcoin transaction is always increasing(Batching, Segwit, Lightning, etc). As bitcoin becomes more of a settlement network, each unit of energy is securing exponentially more and more economic value.
  • ASIC’s are actually extremely efficient at converting electricity to heat. +99% efficient. This heat can be recycled.
  • Almost all mining is being done with renewable energy right now. Most principally unused hydroelectric in china that would simply go to waste without those ASIC farms capturing the energy
  • When comparing the energy used in mining to traditional fiat you must analyze all the energy consumed in regulation, auditing, accounting, building infrastructure, security, ect to fairly compare the two

The whole point of Proof of Work is to tie the security of the network to something tangible and expensive, so it cannot be attacked without a huge sunk cost. It’s a feature, not a bug. This energy cost is not wasteful, it is necessary for the security of the chain.

If you need a tank, you can’t complain about it’s weight. Its weight is one of the reasons for its robustness in the first place (or at least it’s an implication of its armor).

The Bitcoin ledger can only be immutable if and only if it is costly to produce. The fact that Proof of Work (PoW) is “costly” is a feature, not a bug. Until very recently, securing something meant building a thick physical wall around whatever is deemed valuable. The new world of cryptocurrency is unintuitive and weird — there are no physical walls to protect our money, no doors to access our vaults.

And most the crucial point; that PoW is the only known mechanism to ensure neutrality and objectivity, from which we get immutability, censorship resistance, permission-less open blockchain… Something that is overlooked by many, but is foundational criteria to be considered a cryptocurrency.

Proof of Stake

PoS adds governance and subjectivity again, which turns it in to a community fiat system (just a bad one, given that 1 vote is given per coin rather than per person as in most democratic governance systems).

Mining in PoW is external, but stakers in PoS are inside the ledger. In other words, full nodes cannot get rid of stakers in PoS systems, even if they split. This means PoS is not censorship resistant as censors cannot be evicted. Sleeping with the enemy is not fine.

There is really no such thing as “staking” in PoS, it’s just a group of trusted rich participants controlling the system. Miners are, in fact, real stakers because they do sink capital in equipment, data centers, and electricity, and can only recover their investments after mining for months if not years.

Proof of Stake is not new or very interesting, and exists as a form with fiat currency already. Proof of stake has many more attack vectors(nothing at stake attacks, long range attacks, short range attacks , stake grinding attacks) than proof of work and ultimately is either less efficient or less secure.

With PoW (proof of work) you would need to be a tremendous amount of effort in order to censor 1-2 blocks with building many asic mining farms, and than burning the electricity continuously in order to attack bitcoin.

With Proof of stake all I need to do is be an early adopter(s) , hack/kidnap an early adopter(s) , or convince many users to join a interest bearing bank account by staking their coins with my company(done many times before) to attack the network. Since Proof of work involves outside resources one can always objectively see and measure the hashrate and sources in realtime and one can cutoff such an attack because it involves outside resources.

There are many different variations of proof of stake but the simplest way to understand this is by looking at those blockchain’s as a democratic consensus mechanism where everyone’s vote is weighted based upon how many coins or stake they control. Their staked coins than have an opportunity to create a block without proof of work and a dev controlling 51% of the coins gets to virtually mint ~51% on average of all the blocks . This presents another concern as the coins typically need to be in “hot wallets” to do so instead of cold storage leading to a more insecure environment.

Since most PoS coins have massive premines where only a small number of devs control most of the coins this also presents another concern as those devs can be targeted by states , hackers, or attackers or as we often see with altcoin devs they pump and dump a project and than move onto a competing project to repeat this cycle over and over again thus have an incentive to attack their old project.

With Proof of work, seizing the coins or stake of any individual or group of people doesn’t effect the process of mining or securing the network directly at all . They can only try and spook the market by dumping coins at a discount while individuals like myself will happily buy up all the discounted coins.

Fiat currency and PoS coins cost at least the same amount of resources to create, regulate, and secure as Bitcoin. PoS is being sought because it is a clever marketing ploy to attract environmentalists who are concerned about the electricity used in PoW mining.

Further Reading:



View at Medium.com

Why Proof of Stake Is Less Secure Than Proof of Work

Click to access ARKInvest_031220_Whitepaper_BitcoinMining.pdf

Troubleshooting and Install of the BL Touch on the Ender 3 Max (or others!)

The BL Touch is a wonderful tool to enhance your 3D Printing setup. Like me, you were probably expecting a plug and play style installation. What reality ends up being is you’ll likely run into multiple issues. Thankfully, after spending 12+ hours troubleshooting, there are some things I hopefully can share for some of you who are still scratching their chin trying to get their BLT setup for the first time. 

At the writing of this guide, 2021, most people likely are new owners of 3D printers and will probably have a Ender 3 4.2.2 32 bit board , so this guide is tailored to that. 

I must give credit to this guide for helping me out, at least half way, and encourage you to use it as reference as well (if applicable). I’d like to echo this author and encourage you get at least the 1.5 meter extension cable, as the 1 meter wasn’t quite cutting it. 


Referencing the above guide, we see this diagram below for the wiring on a 4.2.2 board: 

For my scenario, I purchased the antclabs type extension cable (right).

While the wiring diagram is accurate, the pin connectors are just not quite the right fit. Although slightly smaller, they do slide in there, and do indeed make a connection, but are extremely prone to sliding out, especially the two slot connector. Even if they don’t slide out, they can still lose connection, even while physically still being in the slot. You wouldn’t believe how many time how confident some of my issues weren’t wiring, when they were just that. So keep an eye out for that.

On that note. If you received those cables, they are known as Dupont connectors, and what it’s connecting into is what’s known as a JST XH slot. Although similar, and they kinda fit, your best bet is to splice in the proper connector (JST XH), print out the connector ends if you can (I couldn’t with my nozzle size), or simply glue gun the connectors the lazy way, like I did. 


Below is another wiring guide for 4.2.X boards, use with caution and as a last resort. It should work in theory, as you’re just replacing the Z endstop connector with the BLT signal cable (2pin). Though, many people have these connectors occupied and glued in. 

Z-Axis Issues

If your BLT is lighting up, but refuses to go down in the Z-Axis, it could be that the two pin connector isn’t making contact on the board. 

Brown/Red/Yellow cable is three pinned, less prone to losing contact, and it’s the power to the BLT, it also controls the pin going up and down. The two pin black/white connector is responsible for controlling the Z axis. If you haven’t secured this pin with the proper connector or glue, consider troubleshooting it by holding the pin in gently while running a bed leveling test, moving it around or reseating it as necessary until the test can successfully move downward on the Z-axis. 

Firmware issues

When I attempted to follow the above Smith3D guide, the included pre-combiled .bin for the Ender 3 Max with BLT didn’t work for my printer. So I compiled my own using Marlin 2.0.8 and configured for the Ender 3 Max. Feel free to download it!


  • Many connectors sold on Amazon come with Dupont connectors, which connect to a JST XH on the 4.2.2 board. It does fit, but it easily can slide out of place. Even if it physically looks in the slot, it can lose connection due to the larger holes.
  • Consider splicing, printing out the right connector size, or glue gunning for the above issue.
  • If your Z-Axis won’t move down, it’s because your white/black connector is loose.
  • If you own a Ender 3 Max with BL Touch, included above is a 2.0.8 Marlin firmware (newest) that has all BL touch features enabled
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