Interfacing a TENS unit with my HTC Vive (VR) - Page 1
Forum section: electronics / projects

author: os40la
author_rank: Regular Contributor
timestamp: August 09, 2019, 04:28:57 pm
content: I'm working on the idea of interfacing a TENS unit with my HTC Vive (VR). This should make a MUCH more immersive game play.I'm in the early research phase at the moment. Trying to figure out the best way to wire the TENS without hacking the unit. So far I'm thinking about using standard mechanical relays. This method should make it compatible with most units on the market.My Thoughts on accomplishing task at hand.ESP8266 (battery powered) on PCB board with relays. ESP8266 configured as WIFI server receiving UDP requests to trigger the TENS electrodes.Since I will be creating the VR GAME using Unity, the triggering of the TENS electrodes during game play should be a fairly easy task to get working.The TENS voltages should be around 350v. Does anyone have any thoughts on using standard relays and should this work?

author: KMoffett
author_rank: Regular Contributor
timestamp: August 09, 2019, 04:53:59 pm
content: This looks like a "Hold my beer, and watch this!" project.

author: os40la
author_rank: Regular Contributor
timestamp: August 09, 2019, 05:07:01 pm
content: Since this method should only simulate plugging / unplugging the electrodes from the unit. I imagine my beer should be relatively safe. However to be on the safe side I will hand off the beer as you suggested.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 09, 2019, 07:12:20 pm
content: So you're thinking of giving the user electric shocks for a more immersive experience?Kidding aside, could be interesting, but you'd really need to care about safety issues. Some of those stimulators (especially for muscle stimulation, I don't know if you're including those or not in your TENS definition) can be pretty dangerous if misused, for instance placing the electrodes at the wrong place...Also, you'd have to make sure "wiring" the TENS as you said does not break its inherent safety. Putting anything between the stimulator unit and the electrodes could be a safety hazard.Another related issue is that your system wouldn't allow to control any of the TENS parameters, which is a good thing per se, but also a bad one, because the settings (current, pulse width, frequency, etc) would completely depend on the user, and they may take risks they would not otherwise.Sure if you're considering interfacing ready-made units, you may be thinking that all safety concerns are upon the TENS manufacturer's shoulders and not yours, but if you're inserting things before the electrodes, you're effectively modifying the device. Besides, if the intended use is recreational, that could mislead people in using the TENS device with much less precautions that they would otherwise do (again parameters-wise or relating to the electrodes' position)...Just saying.

author: os40la
author_rank: Regular Contributor
timestamp: August 09, 2019, 08:20:51 pm
content: I have already thought about what you mentioned. Only intending for personal use. I have someTENS units already and know about the invalid places to put the pads. Heart area, head, neck area etc… Haven’t seen testes on the list , however I am going out on a limb here an avoid that location as well.They are just the normal ones you can buy online everywhere. The parameters will be controlled from the TENS unit set to the settings I use normally.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 09, 2019, 08:39:13 pm
content: If you're doing this for your own use and know the risks, that's OK. Publishing the thing and encouraging random people to do the same would be already less OK IMO.Anyway, if you still want to experiment, the advice I would give here is to make sure whatever electronics you put between the stimulator's outputs and the electrodes is strictly powered from a power source properly isolated from mains. So I strongly suggest using battery-operated stuff only, and never recharging the battery WHILE you're using your system. That way the probability of adding safety risks would be kept low.

author: os40la
author_rank: Regular Contributor
timestamp: August 09, 2019, 08:59:47 pm
content: I agree. I never intend to use anything other then batteries. The complete system will be isolated. That is why the triggering is via wifi. I will not do any modifications to the TENS. Need to keep the safety features intact.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 09, 2019, 09:17:59 pm
content: As for relays, if you can avoid mechanical relays (although they'd be pretty simple to deal with), that would probably be better in terms of "experience". The clicking noise could get pretty annoying, but that's just an opinion. That said, you would then need to implement a solid-state switching solution that can handle hundreds of volts and that would leak very minimal current, not trivial either.

author: os40la
author_rank: Regular Contributor
timestamp: August 09, 2019, 09:35:45 pm
content: I am looking at using the mechanical relays for keeping it simple. My yelling should be louder than the switching noise.So that shouldn't break the immersion either. It just may add to the force feedback as an extra bonus too