ThermApp Pro: lens covers, lens threading, and power - Page 1
Forum section: electronics / general

author: therwp
author_rank: Contributor
timestamp: October 31, 2020, 10:02:57 pm
content: I recently purchased a ThermApp Pro. I love the thing, but am lost on the answers to a few questions:1. I purchased an additional 35mm lens. It arrived as shown, with no lens cover for either end. That's not going to work long-term. It appears that both sides are designed to accept a hard cover that clicks into place, but I don’t know what that type of connection is called. What should I be searching for?2. I am interested in hunting down a 100mm germanium lens. Is lens threading standardized, or do I have to look for something specific if I want another lens that I purchase to fit?3. Is it possible to use this thing for longer than the capacity of your phone battery at full charge? I considered some sort of Y-splitter that would allow me to inject power... and that's how I discovered that USB OTG disables phone chargingcompletely, at least it does in the Galaxy S9+. I can't even charge it using a wireless charger when the ThermApp Pro is plugged in. What gives? Is there a solution?Thanks!

author: Ultrapurple
author_rank: Super Contributor
timestamp: November 01, 2020, 12:49:46 pm
content: The ThermApp Pro is a fine camera. I have serial # 0001!1 - The lenses aren't normally provided with caps, unlike (for example) DSLR lenses. I'm afraid you'll have to improvise. I keep my not-in-use lenses wrapped in a small lens cloth (from spectacles) to keep the dust out and inside something like an aerosol or roll-on deodorant lid (whatever fits) for physical protection.Some thin plastics such as Cling Film (?Saran Wrap?) don't affect the thermal transmission much and are a way of keeping muck off the lens for at least a while. Here's an example:2 - There aresomecompatible 60mm and 100mm lenses. This is a 60mm that was certainly available a while ago (click image for more info):I think a 100mm maybe available from the same source - which happens to be the guy who wrote ThemViewer.The Inframetrics x3 telescopes work very well and may cost you much less if you're lucky: someone reported recently picking one up for $40 but $100 to $300 is more normal. Here's an early and somewhat inelegant experiment:The telescope is inverting so you'll need to mount the ThermApp upside down or flip the image in software.3 - This largely depends on your phone. I haven't had any success using any kind of 'Y' adapter with any of my many phones; it seems the USB socket is usually hard-wired for DC output when OTG is in use. One thing I found with my Samsung Galaxy S7 is to use the QI charging facility: that works fine at the same time as OTG is in use. But the same trick didn't work with my old Nexus 5, which also is QI-compatible.Depending on the precise hardware you're using, it is sometimes possible to connect a powered USB hub to the phone, which will then provide power to the camera. This will lead to somewhat longer (but not infinite) battery life. Many of the cheap powered hubs seem to back-feed power up the cable to the host, which can result in USB OTG shutting down and the phone going into charge mode.As an aside, I was driven nuts by this when I connected a powered hub to my PC, which subsequently failed to boot and it appeared I'd killed the machine's PSU. Replacing the PSU (at great expense) didn't do anything but I finally had a lightbulb moment and realised it was the power back-feed that was confusing the PSU and preventing it from starting up. So I now have a spare, obsolete, PSU...Hope this helps.

author: Fraser
author_rank: Super Contributor
timestamp: November 01, 2020, 01:01:48 pm
content: For lens caps look for binocular lens caps on eBay. They come in many sizes. I prefer the rubber ones myself.https://www.ebay.co.uk/itm/Lens-caps-lens-covers-for-binoculars-telescopes-monocular-optical-accessory/401510815290?hash=item5d7be8d63a:g:2zkAAOSwSrNaE1pWFraser

author: therwp
author_rank: Contributor
timestamp: November 05, 2020, 07:16:34 am
content: Thanks, Ultrapurple! That was super helpful!I wonder if it the ‘OTG kill charging’ logic is hardware or firmware. If the latter, it should be changeable, at least for some devices.

author: therwp
author_rank: Contributor
timestamp: November 05, 2020, 07:18:58 am
content: Quote from: Fraser on November 01, 2020, 01:01:48 pm:Thank you. I’ll explore that. I’m a bit puzzled, though. What are the notches on the lens lip for, if not ‘an attachment’ of some sort?

author: Fraser
author_rank: Super Contributor
timestamp: November 05, 2020, 11:02:16 am
content: Such notches are unusual, but not unheard of, on a lens barrel. Normally they would be provided in order to use a lens tightening or loosening tool. Nothing to do with a lens cap or other attachment. I note that the lens barrel is internally threaded so it can have any attachment screwed into it, just like on an SLR lens. You could use a photographic lens cap that clips into the internal threads but you need to check the clearance of the lens cap with the front lens to avoid scratching.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 05, 2020, 11:15:28 am
content: The Umicore catalogue shows the notches in some of the lenses, including yours, but no mention of their intended purpose. There is mention of an optional lens protector window that may be screwed into your lens front thread however. I suspect the notches are for the use I previously mentioned..... a convenient way to mechanically couple to the lens for tightening or loosening it when installed in a camera. These are generic use lenses so the lens could be buried deep inside a housing and not easily accessed for focus adjustment, installation or removal.https://eom.umicore.com/en/infrared-optics/products/optics-catalogueFraser

author: JohnG
author_rank: Frequent Contributor
timestamp: November 30, 2020, 06:19:17 pm
content: Quote from: therwp on October 31, 2020, 10:02:57 pmI could never get the OTG power functioning with a Razor phone, so battery life was a killer. Since I often used this on the bench to monitor things running all day, or longer, it ended up being a huge problem, and Opgal provided no useful help. I tried many recommendations online to trick USB-OTG into allowing charging with something plugged in, involving spliced cables and resistor values, but basically this was a USB-OTG promise that was never fulfilled and the world moved on.I solved this in the end with a Lenovo TAB4 8+,which has USB-C. Then, I have a powered USB-C hub (this one:https://www.amazon.com/Trianium-Aluminum-Pass-Through-Charging-Chromebook/dp/B074DRW84M). I power the hub through via an AC adapter, and this powers both the ThermApp and the tablet indefinitely, which makes it usable on the bench. It works, but don't leave the hub plugged into the tablet/phone/whatever without ac power, or the hub will drain the device, even without the ThermApp attached. Hope this helps.John

author: therwp
author_rank: Contributor
timestamp: June 08, 2021, 01:40:02 pm
content: Quote from: JohnG on November 30, 2020, 06:19:17 pmDo you have any idea what’s going on in  USB hubs that makes this work? Naturally, hubs are designed to host more than a single accessory — which makes them unnecessarily bulky for our purposes. I wonder if its reasonably possible to make a “hub” in the form factor of an OTG + charge adapter.

author: Ultrapurple
author_rank: Super Contributor
timestamp: June 08, 2021, 03:46:21 pm
content: There is a bit of a saga on theTherm-App Pro and USB-C hereincluding X-Rays of cables and all sorts of other fun.I have yet to find a method of powering a phone with Therm-App, Pro or otherwise, except via a QI charger slapped on the back of the phone - and that only works withsomeQI-compliant phones. Some some (older?) phones don't support QI charging at the same time as running an OTG peripheral. I can confirm that the Samsung S7 and Samsung S20 5G (non-USA) do work OK; an old Nexus 5 doesn't.I have tried several USB-C hubs, though not with the camera attached, and had mixed results. They either don't work, or will work provided they're plugged into the phone when it's in the mood to play ball. I nearly threw away one hub before realising that it would only work if I plugged it into the phone when (a) the phone was awake and (b) the hub had a USB memory stick (of any sort) attached. After it had recognised the hub I could remove the USB stick and plug other things in.USB OTG: As seen in theJournal of Irreproducible Results.