What is Detective Hour and how does it work?
What is "Detective Hour"?
Detective Hour, or simply DH, is the unit used to measure the time The Detective spends watching your prints. Details here.
It is indicated by the symbol 
in the system.
Why do I need Detective Hours?
You need a positive balance of Detective Hours on your account to have The Detective watch your prints. Here is why.
How do I get Detective Hours?
There are several ways to get Detective Hours:
You can earn Detective Hours by helping The Detective get better.
If you have the Free plan, you will get 10 Detective Hours for free each month.
If you subscribe to the Pro plan, you will receive 50 DHs as part of your subscription each month.
You can buy or subscribe to one of the Detective Hour packs.
Where can I check the DH balance on my account?
There is an icon at the top of the page that shows the current DH balance on your account. You can click on that icon and see this balance broken down to the DHs included in your plan and the DHs you earned or bought.
What will happen if the DH balance on my account goes to 0?
When your Detective Hours run out, The Detective will stop watching your prints, and you won't get alerted even if your prints start to fail. Everything else remains the same. You can still start, pause, or cancel your prints in OctoPrint or The Spaghetti Detective. Your webcam feed will stream as usual too.
I heard I can buy more DHs. Is it true?
Yes. Additional DHs can be bought at $20 for 500 hours, or $0.04/hour. If you have subscribed to the Pro plan, you can also add one of the Subscribe&Save DH packs to your Pro plan at a much lower rate.
Go to your subscription page to buy more DHs.
10 FREE DHs per month for free account? Why do you do that?
Because we love 3D printing and we love our users. Even if 10 DHs per month is not a lot, if you turn on detection only for your "risky prints", it can still significantly reduce your stress level, and sometimes save your printer from a jammed heater block or fan.
Tell me more about the DHs that are included in the Pro plan.
If you subscribe to the Pro plan, you will get 50 DHs every month. If not all 50 DHs are used when the month ends, the unused DHs roll over into next month, as long as you keep your subscription active. The same roll-over rule applies to the DHs that comes from the Subscribe&Save DH Packs.
Here are some nitty gritty details.
What happens to the balance of my DHs when I cancel my subscription plan?
If you cancel your subscription plan, the remaining DHs that originally came from the Pro plan or the Subscribe&Save DH pack will expire at the time when the plan ends.
You will get to keep the DHs that you bought in a Pre-paid DH pack, or earned by contributing to The Detective's learning.
Is there an easy way to tell The Detective not to watch my prints when I don't want to use DHs?
Yes! We have redesigned our printer page to make it super easy! We have also added visual cue so that it's clear when you are not using your hard-earned DHs.
Tell me exactly how DHs are accounted for.
1 DH = 1 hour worth of time when your printer is printing AND The Detective is actively watching your print.
This means the time when your printing is idle (not printing) won't be counted as DHs. Also, when you disable detection for a print, or for a period in a print, that period will not be counted as DHs either.
Let's use an example to illustrate how Detective Hours are accounted for:
| Start | End | Activity | Duration | Is DH? | Explanation |
|---|---|---|---|---|---|
| 6am | 6:15am | You turn on the 3D printer. Then you prepare the G-Code and the print bed | 0.25 hours | No | Not DH when printer is idle. |
| 6:15am | 7am | You start the print. Your printer prints happily. | 0.75 hours | Yes | |
| 7am | 7am | The Detective sends you an alert. It's a false alarm caused by gyroid infill. So you disable detection. | 0 hours | ||
| 7am | 8:30am | Your printer prints happily and finishes the print. | 1.5 hours | No | Not DH when detection is disabled. |
| 8:30am | 5pm | Your printer is left on when you are at work. You turn it off after you come home. | 8.5 hours | No |
In this example, only 0.75 DHs are accounted for, even if the print lasts 2.25 hours, and the printer is left on for 11 hours.
Why do you make it so complicated?
The reason why we took the trouble to properly account for DHs is because every single costs computational resources.
When The Detective is actively watching your print, the TSD server continuously analyzes the pictures sent from your webcam. This analysis, known as Deep Learning, uses an expensive resource called GPU.
This is exactly why we took the trouble to program The Detective so that she doesn't spend any time watching when you are not printing, or don't want her to watch your prints.
Also by accounting for the usage of DHs, we want to motivate everyone to optimize how we use our DHs. Only by doing so can we provide this service to the entire 3D printing community at affordable cost.
Tell me exactly how DH's roll-over works.
First of all, there are 2 different kinds of DHs.
The DHs that are included in your subscription plan. For instance, the Free plan includes 10 DHs per month; Pro plan includes 50 DHs per month. There are also "Subscribe&Save DH Packs" that include various number of DHs each month. Let's call them included DHs.
The DHs that you buy in a Pre-paid DH pack, or otherwise earn by teaching The Detective. Let's call them earned DHs.
Here are the complete list of all roll-over rules on DHs:
The balance of included DHs roll over into next month, as long as the subscription is kept active. The roll-over happens when the next billing cycle is fully paid for.
The balance of earned DHs roll over infinitely. It doesn't matter if you have a subscription plan at all.
To minimize the amount of included DHs you would loose should you cancel the subscription plan, included DHs are always used before earned DHs.
A complete example to show how Detective Hour works.
| Date | Activity | Earned DHs | Included DHs | Total DH |
|---|---|---|---|---|
| 1/1/2020 | Earns 20 DHs by uploading 20 time-lapses | 20 | 0 | 20 |
| 1/5/2020 | Prints 10 hours | 10 | 0 | 10 |
| 1/10/2020 | Upgrades 2 printers to Pro plan | 10 | 50 | 60 |
| 1/15/2020 | Prints 24 hours, with detecting disabled for 4 hours | 10 | 30 | 40 |
| 1/20/2020 | Earns 25 DHs by uploading 25 time-lapses | 35 | 30 | 65 |
| 1/25/2020 | Prints 40 hours (2 printer total), with detection disabled for 2 hours | 27 | 0 | 27 |
| 2/10/2020 | Renews Pro plan | 27 | 50 | 77 |
| 2/15/2020 | Cancels Pro plan | 27 | 0 | 27 |