Thinking about getting a power meter and some sort of device that will run Xert for smart outdoor workouts (unfortunately my phone is iOS and I don’t have a bike computer). Does anyone have a setup on the affordable end of the spectrum they are happy with? Right now my cadence and HRM sensors are ANT+, so a bluetooth-only setup would mean replacing them too.
Here’s some possibilities –
- CABLE (Connect ANT+ to BLE) - North Pole Engineering, Inc. Store (npe-inc.com)
- New or used small form factor Android phone to run EBC.
Example: Cubot King Kong Mini 2 - General - Xert Community Forum (xertonline.com) - Garmin quarter-turn adapter for back of phone (or back of phone case)
Example: Xert EBC - Garmin out front mount; several brands/copies available
Example: https://www.amazon.com/KOM-Cycling-Garmin-Carbon-Designed/dp/B01MSWB5FW/ - Stages or 4iiii left crank meter
Another phone option is a used Android phone (smallest you can find with decent battery life) plus a stem mount like this one:
Amazon.com: Bone Bike Tie Pro 4 Bike Phone Holder for Stem Mounting 4.7” - 7.2” Screen Smartphones, Face ID Compatible, Ultra Light Weight Bicycle Phone Mount, Designed for Road, Race & Touring- Black: Automotive
No SIM card needed. Use phone as your bike computer and connect by Wi-Fi to XO as required. Disable Wi-Fi hunting on outdoor rides to save battery.
Also note many used Samsung models will have ANT+ chip onboard so you could nix the CABLE bridge and the phone will connect to all your sensors. The crank meter will be dual protocol.
So least expensive combo would be used Samsung phone with ANT+ with the looping stem mount above plus a left crank meter. 
Or maybe Favero Assioma pedals (Uno or Duo). Easy to install and easy to swap between bikes.
An old Android phone might be lying around a friends house if you ask around. If the mount you use allows it you can use an Ant+ stick with an on-the-go adapter or similar. Might also be lying around somewhere not needed any more. Ant sticks came with old Garmin devices to sync to PC and they were used to connect trainers to PCs before everything was Bluetooth capable. And people with old phones with Micro USB might have a on-the-go cable from Micro USB to USB that’s not used any more. With an old phone you have to check for battery, rain sensitivity and screen capabilities in the sun though,
Just some ideas.
If you have a garmin watch you can add Xert data fields to some, then ride to a target ‘focus’? (Just guessing as you have HRM and cadence sensor… or do you just have these for indoors…)
Else if you want to ride and don’t care about GPS you can use the iOS player? You’ll miss HR and cadence though.
For powermeters you can try Assioma uno or a single sided crank based one as @ridgerider2 suggests. Cheaper still is the power pod, which apparently is surprisingly accurate. DC Rainmaker has loads of detailed reviews and a buying guide
Last year, I got my second powermeter from China (AliE…), a XCadey for about 200 €.
I put it on my “fitness” bike (Canyon RoadLite) for my gravel rides (with larger tires, 38mm if I remember), and I’m fully satisfied. I have the same output as with my “Stages 2” PM on my road bike.
Can the CABLE device connect sensors to several apps simultaneously ?
It only serves up 1 BT connection per sensor however a common use case is for one app to connect to the power meter’s native BT interface and use the Cable to create another interface that converts ANT to BLE so that you can connect a second app to the same power source.
That seems tricky 
I think the cheapest is a left side power meter like Stages or 4iii and a Garmin edge bike computer, which is much less expensive that a smart trainer. Not cheap, but you can also use this setup indoors on a dumb trainer in the winter. Samsung android and some other phones support ant+, but I you might need to charge the battery. Crank based power meters also measure cadence.
Thanks for all the great suggestions! I do have a Garmin Fenix watch which has served as my “bike computer” quite well, but I’ve always struggled with outdoor structured workouts using it; I haven’t had a power meter, and the places I ride have enough traffic lights and congestion that having something which adapts the intervals as needed like Xert does would be amazing.
I hesitate to pay a double garmin tax to get a computer, but then the trouble of finding a rainproof setup for an Android device might push me there. Really appreciate the various power meter suggestions… I ride a cheap bike (early 2000’s steel frame roadie) so it’s seemed a bit silly to rig it up with electronics worth several times it’s cost, but after training with power indoors all winter I’m thinking about it.
I think some are using the Xert app on a Cubot King Kong Mini. I’ve seen them selling for $100 on AliExpress.