Handheld Scientific Bluetooth Adapter BT-500

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21 Jan 2019, 14:57

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Few weeks ago I was contacted by Alan from Handheld Scientific who asked if I was interested in reviewing their Bluetooth Adapter. I eyed the little wireless dongle a while back when it still came with a battery and always thought I could make good use of it, so I accepted without hesitation. From what I read around this is not a special treatment reserved to me because I'm a robot but it seems Handheld Scientific is willing to give your money back in exchange for reviews on social medias (at least at the time of this writing).

So. Bluetooth Adapter BT-500, won't pass into history for the originality of its name but the premises are appealing: to convert any wired keyboard (or mouse) into a bluetooth cord-less device. What a treat.

The previous version came with a battery, the new one is smaller and sleeker but doesn't provide any kind of power. Meaning you have to provide the required juice, being that a USB charger, a standard USB port from your PC or a power bank (so fashionable nowadays).

Of course they can't foresee what device will be hooked to the dongle so they left the power issue to the user. Say you want to use a fully backlit keyboard, no problem, connect a beefy battery and you can go on for hours.

I feel the perfect scenario for the BT-500 is hooked to a USB charger near your desktop, paired to a tablet or smartphone that will be easily accessed through your precious mechanical keyboard. While it can be surely hacked into a wireless companion, I don't feel you can call it "portable" considering you have to add a battery pack and also it's not certainly tiny dongle (66x25x14mm).

Let's try it out

I put the dongle in my desktop PC just for the power and connect it to the most vanilla keyboard I have around, a Cooler Master Masterkeys pro. The idea is to try it on an iPad, I knew that that had the most chances to work. Indeed the 5-6yo tablet sees the dongle without a glitch but -alas- the keyboard doesn't seem to be working.

Check the cable. Recheck the connection. Try the keyboard without the dongle. Everything's fine but simply the BT-500 is not compatible with that specific Cooler Master. If that were my only keyboard it would have been a disaster, but as anyone in this forum I have plenty of fancy typing devices around. As soon as I connect a WhiteFox everything works right away and all the frustration forgotten...

... Apart that the dongle by defaults acts as USB passthrough too. My PC --that is used just as a power supply-- receives the keystrokes together with the ipad. You can disable this feature by pressing the only button on the bluetooth adapter but I feel by default the dongle should be in BT only mode because bad things could happen. Also, the dongle doesn't retain the mode you put it in, so if it loses power it will be back to USB passthrough.

The LED could be a little more explanatory about what mode the adapter is in. My suggestion: Blue for bluetooth, Yellow for USB only, Green for both (you see where I'm going?).

Time to try our little friend with a Windows laptop. To my surprise there's no way from the dongle to change or even un-pair a previously paired computer. By holding the button for 10 seconds the BT-500 is reset to factory defaults, but my iPad was still paired and the only way was by opening the tablet preferences and by disconnecting the dongle from there.

At that point my laptop was more than happy to connect to the adapter and the keyboard was finally happily click-claking around.

Latency is very good, but forget to use it for gaming, but that is generally true for every wireless device.

Command mode

By holding the button for 2 seconds the device goes in command mode. Apparently the command mode only works via bluetooth and it didn't work for me with the adapter connected to a PC in passthrough mode.

The Command mode sends its output to a text editor and you talk to it with the paired keyboard. There are a multitude of options there, the most interesting is probably the keyboard mapping. When the dongle receives a keystroke you can tell it to output something else. Very useful if you can't customize your keyboard firmware. A little sad to see that it doesn't seem to support any UTF-8 character. Just standard ANSI and a few media keys, but useful nonetheless.

From the command mode you can also set timers --to send a periodic ping and void bluetooth timeouts-- and macros. All in all a very nice feature set, but probably the command mode would need an easier interface to be accessed from.

Just a side note. If you hold the button for 10 seconds the adapter resets, but after 2 seconds the command mode is initiated anyway. So the BT-500 goes into command mode before it resets. Be sure to disconnect your keyboard before a reset because the adapter will send all the command mode characters to the device and the result could be unexpected.

A full description of the command mode can be found on handheld scientific website.


The ideal use case for the Handheld Scientific Bluetooth Adapter is with one and one only keyboard/mouse taking power from a power bank or USB charger. In that scenario it's a setup and forget little thingy. If you plan on using it on multiple computers/tablet/phones it's a frustrating experience. Also the USB passthrough is more of annoyance than a feature, technically it could act as a switch from USB to bluetooth so you could use the same keyboard alternatively on PC and --say-- an Android phone, but in reality it's not very practical.

My suggestion to make the BT-500 a more general purpose device would be to add a button to cycle between at least 3 devices and make it very easy to switch from one mode to another (usb/bluetooth/both). Would be nice to be able to set a macro to shift device and/or mode for example.

That being said, if you have a vintage keyboard like a Model F with a lot of room inside, placing the BT adapter with a huge battery bank in the belly of the beast would make your hipster input device into a sassy wireless companion to bring with you at Starbucks or local bar.

Also, before you buy be sure your keyboard is compatible, because my Cooler Master didn't work. Maybe because it's a gaming keyboard (I believe it has troubles accessing the motherboard BIOS too). The SK630 (still Cooler Master) works though, so it's not brand specific, but more something with the firmware. Good news is that custom firmwares like TMK work like a charm.

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21 Jan 2019, 18:03

I'm curious if it can be stripped down and placed inside a FC660c like this mod over here:


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21 Jan 2019, 18:12

AdrianMan wrote:
21 Jan 2019, 18:03
I'm curious if it can be stripped down and placed inside a FC660c like this mod over here:
yeah that would be totally doable. You don't even need to strip it down. Just add a battery, it would probably fit with the casing.

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21 Jan 2019, 20:03

Hmm. I do like me a bit of Bluetooth, but this dongle has always put me off. There’s the size issue—I want Bluetooth *inside* the keyboard, not hanging off the back—and now there’s the “bring your own” power issue too. This converter is the kind of thing I’d want to run off a 3.3v battery, using USB for charging and (like Matteo) as a mode switch for toggling control between two separate hosts. Frustrating to see they’ve got it all so wrong.

The programmability is interesting, if awkward. But really, I’d prefer to see Hasu make something like this, with the deep and powerful features of his own Bluetooth HHKB controller, but for all USB keyboards.

Incidentally: I know why the programmability doesn’t extend to Unicode. It’s actually down to the Bluetooth human interface device spec. Just like USB, compliant keyboards are only permitted a specific list of key codes. Unicode goes well beyond this list. Maybe someday Bluetooth and USB HID will be updated to reflect this. But then again maybe not.

Also: the weird way this Bluetooth device connects to its host is much like Hasu’s HHKB controller. I believe it’s because they both use the same low cost Bluetooth chipset, though I could be wrong. What I get with my Hasu HHKB is automatic reconnect to the presently active device whenever cutting the link at the host. This isn’t ideal, but it’s something I work around easily by turning off Bluetooth on the iPad whenever switching to the Mac, and vice versa. Hasu’s controller has a list of paired devices and goes on to the next one. It would be better if it was less persistent about reopening the just closed connection, but I can forgive this in such an epic wee self-made project. In a commercial product, meanwhile?
Anyway, Bluetooth is big, for those of us with mobile needs, and who still pack mechs! This hardware, as Matteo says, is more suited to a tethered environment, where USB power is always available. It’s not something I see a use for, for myself.


22 Jan 2019, 14:45

I have their previous version that has the internal lithium battery and I was eventually planning on implementing this inside of a beamspring, but I'm a little picky when it comes to function and I want to be able to switch between wired and wireless use and whenever USB is connected, I want the battery to charge. I think with enough switches and a separate battery charging circuit, this should be possible. You can definitely upconvert 3.7v to 5v so that you can use standard lithium batteries and there's plenty of room in a beamspring case for batteries and such which is nice.

One of the main downsides of a "simple" solution is that most 5V USB power banks do not behave like uninterruptable power supplies that can charge and supply power at the same time.

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24 Jan 2019, 01:36

DMA has a Bluetooth version of CommonSense in the works. That ought to handle a beamspring very nicely, with all the Xwhatsit style features those of us nerdy enough to use beamsprings and Kishsavers in this day and age demand!

I'd rather have a product like this for modern, commercial keyboards that just aren't controller-swap friendly. With, indeed, the dual mode USB / Bluetooth function that you describe and Hasu already has aced on the HHKB.

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