Omnicore DIY hardware

Omnicore DIY hardware solutions

Introduction

Omnicore does not need special hardware beyond RileyLink. But if you are interested in having less to carry, read on for more custom solutions...

RileyLink in Samsung S7 power case

(Still needs photos adding).

Here is how to put RileyLink (433) in a Samsung S7 battery case. It allows for use of aaps+omnicore with no hardware beyond the phone in its case. PLEASE NOTE this needs electronics / soldering skills so read thru and check you are confident to attempt it before starting.

1. I used this case - https://rover.ebay.com/rover/0/e11011.m43.l3160/7?euid=5016bbf3eb8c4d04bd4ee64c3eef40f4&bu=43165446585&loc=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fi%2F332929203308&sojTags=bu=bu

2. Open case - remove faux velvet sticker, undo all screws (?6), remove metal plate, undo plastic clips and it separates into two.

3. Desolder the battery. Snip away & desolder the large USB power socket.

4. Prepare RileyLink - snip away and desolder white JST battery connector, solder on wires in its place.

4 b. Desolder antenna, replace it with 18cm piece of solid core wire (see below re tweaking the length).

4 c. Remove black socket covers on programming pins.

4 d. I also used a silicone conformal coating to waterproof the RL - I was trying to get a silicone spray one but couldn't get it so used this one instead which you apply like nail varnish to both sides - https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F171365019664 . I made sure to mask the switch & usb connector so not to gum them up.

4 e. I put electrical tape on the back of the RL board to insulate it from the case charging circuit.

5. Prepare case - get a small smd switch (like this:  https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F163792239569 ) and solder wires to it (middle/end poles). super glue it down to case where the usb opening is. make sure it is recessed sufficiently so the throw doesn't protrude/get caught but is also accessible with a pen. tape down wires to stop movement.

5 b. Create a protection around switch with sellotape, and make a 'back' to allow gluing of the usb aperture so it doesn't fill too much. Use epoxy to fill this - aim to create a solid window where usb aperture is, without gumming up the switch. Allow 24hrs to set.

5 c. Place RL into case - RL USB power socket down and facing bottom of case. Use a dremmel with a small routing bit to cut away some case to allow this to fit. I needed to cut a little trough to allow space for RL USB. Make sure switch on RL board turned on.

5 d. Run wire antenna up the left side of case (side furthest form usb aperture), gently bent round top. I needed to use a dremmel to cut away some of the notches to allow it to fit. Tape down the antenna.

5 e. Solder one side of switch to +ve RL power. Cover with heat shrink tube or electrical tape.

6. Get a replacement battery. You need a smaller battery (around 4200mah but the physical dimensions are the most important) to put in place of the 6500mah battery removed from the case. Smaller size important so (i) RL will fit in case top-to-bottom and (ii) there is clearance for areal left to right. The 6500mah removed is dimensions 846088 (ie 8.4mm thick, 60mm left-right, 88mm top-bottom). You're looking for something like 845080 or slightly smaller. I found this difficult to source but found a perfect battery size using the battery out of this iphone battery case, which is 4200mah - https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F293048352985 (that case comes apart in similar way to S7 case... just get the battery out and chuck the rest!).

6 b. Secure battery down with double sided tape on the right hand side nearest the top (ie on usb aperture side).

7. Check for fit with everything. Case charger circuit goes on top of RL. You may need to dremmel more case away to get RL to seat far down enough.

8. Solder power -ve side all together: battery, RL,  case. Ensure switch is off then solder +ve battery, switch and case.

9. Test and adjust antenna. Turn switch on. Lightly place the metal case on top. Get Omnicore going, and use it to establish link with pod. Use 'update' status button to check db loss (between RL and pod, not phone and RL) in conversations tab. Trim antenna down by 1mm and repeat 'update' button. Keep trimming till db worsens (ie gets a bigger -ve). eg If it was -55 then gets to -53 it has got better so trim another 1mm but if results on -56 it has got worse so stop trimming.

10. Shut case. Clip together, replace metal plate, replace screws, replace faux velvet. I managed to damage the clips at the bottom which meant I needed to superglue shut to stop it gaping but shouldn't be necessary if you were careful!

11. The end result... is being able to just carry your normal phone (albeit with a power case, albeit I always had one anyway), and nothing else to manage your diabetes except a pack of sweets... this is a big deal for me! It all works surprisingly well with omnipod and aaps+omnicore. You can see the RL green LED through the epoxy which is a useful reaasurance. When you need to charge your phone press the button on the case - this should give 1-2 charges (but don't exhaust the case battery entirely or the RL won't get power).

In summary this is RL in a phone battery case, sharing the battery with phone backup battery; a wire antenna - up the side of the case (with about 12mm clearance from side of battery) and around the top; an accessible switch for RL.

RileyLink attached to back of phone using 3d printed case

(details to be added)

Waterproof swim-compliant RileyLink with wireless charging

Some things to keep in mind... 3D parts are not waterproof. You can think of them as a sieve and under water the pressure is very high even at relatively low depths. This is sufficient to force water into most 3D designs. First off, you can paint the surface with acetone (nail varnish remover) and this will melt it just a tiny bit but enough to seal the plastic. It is also important to remember that radio waves and water do not play nicely (this is why submarines use sonar not radar). Google "signal attenuation". Basically the higher the frequency, the worse it gets.

Bluetooth uses 2.4GHz which for most CGM/phone combos gives a maximum range of about 5cm in fresh water and about 1cm in salt water. I use the Unihertz Atom (https://www.unihertz.com/atom) because it is waterproof and has an arm strap so you can strap the phone directly on top of the CGM (so long as you wear it on your arm). I tested this with a G6 and a Miaomiao/Libre with no problems in either a fresh water lake in Finland or the Atlantic ocean.

The omnipod uses 433MHz so the range "should" be 5.5x better than Bluetooth at the same number of decibels. Unfortunately the RL antenna is not very good and struggles to keep contact even in air sometimes. Radio theory tells us a few things to help: thicker aerial wires have less resistance which means more broadcast power; longer aerials work better than shorter ones; The length of the aerial is very important - for 433 MHz you need: Full wavelength: 69.27 cm Half wavelength: 34.63 cm Quarter wavelen: 17.32 cm The shorter the aerial, the more small errors matter. For this project I will make a half wavelength aerial